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Sample records for somatostatin receptor antagonists

  1. Somatostatin receptors

    DEFF Research Database (Denmark)

    Møller, Lars Neisig; Stidsen, Carsten Enggaard; Hartmann, Bolette

    2003-01-01

    functional units, receptors co-operate. The total receptor apparatus of individual cell types is composed of different-ligand receptors (e.g. SRIF and non-SRIF receptors) and co-expressed receptor subtypes (e.g. sst(2) and sst(5) receptors) in characteristic proportions. In other words, levels of individual......-peptides, receptor agonists and antagonists. Relatively long half lives, as compared to those of the endogenous ligands, have been paramount from the outset. Motivated by theoretical puzzles or the shortcomings of present-day diagnostics and therapy, investigators have also aimed to produce subtype...

  2. SSTR-Mediated Imaging in Breast Cancer: Is There a Role for Radiolabeled Somatostatin Receptor Antagonists?

    Science.gov (United States)

    Dalm, Simone U; Haeck, Joost; Doeswijk, Gabriela N; de Blois, Erik; de Jong, Marion; van Deurzen, Carolien H M

    2017-10-01

    Recent studies have shown enhanced tumor targeting by novel somatostatin receptor (SSTR) antagonists compared with clinically widely used agonists. However, these results have been obtained mostly in neuroendocrine tumors, and only limited data are available for cancer types with lower SSTR expression, including breast cancer (BC). To date, two studies have reported higher binding of the antagonist than the agonist in BC, but in both studies only a limited number of cases were evaluated. In this preclinical study, we further investigated whether the application of an SSTR antagonist can improve SSTR-mediated BC imaging in a large panel of BC specimens. We also generated an in vivo BC mouse model and performed SPECT/MRI and biodistribution studies. Methods: Binding of 111 In-DOTA-Tyr 3 -octreotate (SSTR agonist) and 111 In-DOTA-JR11 (SSTR antagonist) to 40 human BC specimens was compared using in vitro autoradiography. SSTR2 immunostaining was performed to confirm SSTR2 expression of the tumor cells. Furthermore, binding of the radiolabeled SSTR agonist and antagonist was analyzed in tissue material from 6 patient-derived xenografts. One patient-derived xenograft, the estrogen receptor-positive model T126, was chosen to generate in vivo mouse models containing orthotopic breast tumors for in vivo SPECT/MRI and biodistribution studies after injection with 177 Lu-DOTA-Tyr 3 -octreotate or 177 Lu-DOTA-JR11. Results: 111 In-DOTA-JR11 binding to human BC tissue was significantly higher than 111 In-DOTA-Tyr 3 -octreotate binding ( P < 0.001). The median ratio of antagonist binding versus agonist binding was 3.39 (interquartile range, 2-5). SSTR2 immunostaining confirmed SSTR2 expression on the tumor cells. SPECT/MRI of the mouse model found better tumor visualization with the antagonist. This result was in line with the significantly higher tumor uptake of the radiolabeled antagonist than of the agonist as measured in biodistribution studies 285 min after radiotracer

  3. Development and preclinical evaluation of radiolabelled somatostatin receptor agonists and αvβ3-integrin antagonists

    International Nuclear Information System (INIS)

    Stoecklin, G.; Wester, H.J.; Haubner, R.; Schottelius, M.

    2002-01-01

    Tumours express specific receptors for peptide ligands. This can be exploited for tumour targeting. New bioactive peptides are available, in particular new somatostatin analogs and RGD-Peptides for targeting the α V β 3 -integrin. The design and optimization of radiolabelled peptides with respect to their receptor affinity, tumour uptake, biodistribution, pharmacokinetics and stability may provide better tracers for tumour imaging and therapy. Based on two basic structures, new radioiodinated and carbohydrated somatostatin analogs and cyclic RGD-peptides were developed and evaluated. (author)

  4. Evolutionary history of the somatostatin and somatostatin receptors

    Indian Academy of Sciences (India)

    Somatostatin and its receptors have a critical role in mammalian growth through their control pattern of secretion of growth hormone, but the evolutionary history of somatostatin and somatostatin receptors are ill defined. We used comparative whole genome analysis of Danio rerio, Carassius auratus, Xenopus tropicalis, ...

  5. The somatostatin receptor 2 antagonist 64Cu-NODAGA-JR11 outperforms 64Cu-DOTA-TATE in a mouse xenograft model

    Science.gov (United States)

    Rylova, Svetlana N.; Stoykow, Christian; Del Pozzo, Luigi; Abiraj, Keelara; Tamma, Maria Luisa; Kiefer, Yvonne; Fani, Melpomeni; Maecke, Helmut R.

    2018-01-01

    Copper-64 is an attractive radionuclide for PET imaging and is frequently used in clinical applications. The aim of this study was to perform a side-by-side comparison of the in vitro and in vivo performance of 64Cu-NODAGA-JR11 (NODAGA = 1,4,7-triazacyclononane,1-glutaric acid,4,7-acetic acid, JR11 = p-Cl-Phe-cyclo(D-Cys-Aph(Hor)-D-Aph(cbm)-Lys-Thr-Cys)D-Tyr-NH2), a somatostatin receptor 2 antagonist, with the clinically used sst2 agonist 64Cu-DOTA-TATE ((TATE = D-Phe-cyclo(Cys-Tyr-D-Trp-Lys-Thr-Cys)Thr). In vitro studies demonstrated Kd values of 5.7±0.95 nM (Bmax = 4.1±0.18 nM) for the antagonist 64/natCu-NODAGA-JR11 and 20.1±4.4. nM (Bmax = 0.48±0.18 nM) for the agonist 64/natCu-DOTA-TATE. Cell uptake studies showed the expected differences between agonists and antagonists. Whereas 64Cu-DOTA-TATE (the agonist) showed very effective internalization in the cell culture assay (with 50% internalized at 4 hours post-peptide addition under the given experimental conditions), 64Cu-NODAGA-JR11 (the antagonist) showed little internalization but strong receptor-mediated uptake at the cell membrane. Biodistribution studies of 64Cu-NODAGA-JR11 showed rapid blood clearance and tumor uptake with increasing tumor-to-relevant organ ratios within the first 4 hours and in some cases, 24 hours, respectively. The tumor washout was slow or non-existent in the first 4 hours, whereas the kidney washout was very efficient, leading to high and increasing tumor-to-kidney ratios over time. Specificity of tumor uptake was proven by co-injection of high excess of non-radiolabeled peptide, which led to >80% tumor blocking. 64Cu-DOTA-TATE showed less favorable pharmacokinetics, with the exception of lower kidney uptake. Blood clearance was distinctly slower and persistent higher blood values were found at 24 hours. Uptake in the liver and lung was relatively high and also persistent. The tumor uptake was specific and similar to that of 64Cu-NODAGA-JR11 at 1 h, but release from the tumor

  6. Switch from antagonist to agonist after addition of a DOTA chelator to a somatostatin analog

    International Nuclear Information System (INIS)

    Reubi, Jean Claude; Cescato, Renzo; Waser, Beatrice; Erchegyi, Judit; Rivier, Jean E.

    2010-01-01

    Peptide receptor targeting has become an increasingly attractive method to target tumors diagnostically and radiotherapeutically. Peptides linked to a variety of chelators have been developed for this purpose. They have, however, rarely been tested for their agonistic or antagonistic properties. We report here on a somatostatin antagonist that switched to an agonist upon coupling to a DOTA chelator. Two novel somatostatin analogs, 406-040-15 and its DOTA-coupled counterpart 406-051-20, with and without cold Indium labeling, were tested for their somatostatin receptor subtypes 1-5 (sst 1 -sst 5 ) binding affinity using receptor autoradiography. Moreover, they were tested functionally for their ability to affect sst 2 and sst 3 internalization in vitro in HEK293 cells stably expressing the human sst 2 or sst 3 receptor, using an immunofluorescence microscopy-based internalization assay. All three compounds were characterized as pan-somatostatin analogs having a high affinity for all five sst. In the sst 2 internalization assay, all three compounds showed an identical behavior, namely, a weak agonistic effect complemented by a weak antagonistic effect, compatible with the behavior of a partial agonist. Conversely, in the sst 3 internalization assay, 406-040-15 was a full antagonist whereas its DOTA-coupled counterpart, 406-051-20, with and without Indium labeling, switched to a full agonist. Adding the DOTA chelator to the somatostatin analog 406-040-15 triggers a switch at sst 3 receptor from an antagonist to an agonist. This indicates that potential radioligands for tumor targeting should always be tested functionally before further development, in particular if a chelator is added. (orig.)

  7. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues.

    NARCIS (Netherlands)

    Rolleman, E.J.; Melis, M.; Valkema, R.; Boerman, O.C.; Krenning, E.P.; Jong, M. de

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides

  8. Functional somatostatin receptors on a rat pancreatic acinar cell line

    International Nuclear Information System (INIS)

    Viguerie, N.; Tahiri-Jouti, N.; Esteve, J.P.; Clerc, P.; Logsdon, C.; Svoboda, M.; Susini, C.; Vaysse, N.; Ribet, A.

    1988-01-01

    Somatostatin receptors from a rat pancreatic acinar cell line, AR4-2J, were characterized biochemically, structurally, and functionally. Binding of 125 I-[Tyr 11 ]Somatostatin to AR4-2J cells was saturable, exhibiting a single class of high-affinity binding sites with a maximal binding capacity of 258 ± 20 fmol/10 6 cells. Somatostatin receptor structure was analyzed by covalently cross-linking 125 I-[Tyr 11 ]somatostatin to its plasma membrane receptors. Gel electrophoresis and autoradiography of cross-linked proteins revealed a peptide containing the somatostatin receptor. Somatostatin inhibited vasoactive intestinal peptide (VIP)-stimulated adenosine 3',5'-cyclic monophosphate (cAMP) formation in a dose-dependent manner. The concentration of somatostatin that caused half-maximal inhibition of cAMP formation was close to the receptor affinity for somatostatin. Pertussis toxin pretreatment of AR4-2J cells prevented somatostatin inhibition of VIP-stimulated cAMP formation as well as somatostatin binding. The authors conclude that AR4-2J cells exhibit functional somatostatin receptors that retain both specificity and affinity of the pancreatic acinar cell somatostatin receptors and act via the pertussis toxin-sensitive guanine nucleotide-binding protein N i to inhibit adenylate cyclase

  9. Purification of a putative brain somatostatin receptor

    International Nuclear Information System (INIS)

    He, Haitao; Johnson, K.; Thermos, K.; Reisine, T.

    1989-01-01

    The brain somatostatin receptor was purified by affinity chromatographic techniques. A protein of 60 kDa could be purified from rat brain. The protein was eluted from a [D-Trp 8 ]SRIF affinity column with either sodium acetate (pH 5.5) or free [D-Trp 8 ]SRIF. The binding of the protein to the affinity column was prevented by free [D-Trp 8 ]SRIF or the stable SRIF analogue SMS 201-996 but not by the inactive somatostatin 28-(1-14). The purified receptor could be covalently labeled by the 125 I-labeled SRIF analogue CGP 23996. Excess [D-Trp 8 ]SRIF blocked the binding of 125 I-labeled CGP 23996 to the purified receptor, but somatostatin 28-(1-14) did not affect the binding. A 60-kDa protein was also purified from the anterior pituitary cell line AtT-20, which has a high expression of SRIF receptors. In contrast, no 60-kDa protein could be purified from CHO cells, which have no detectable SRIF receptors. These findings present evidence for the purification of the SRIF receptor

  10. Somatostatin receptors in gastroentero-pancreatic neuroendocrine tumours

    NARCIS (Netherlands)

    W.W. de Herder (Wouter); L.J. Hofland (Leo); A-J. van der Lely (Aart-Jan); S.W.J. Lamberts (Steven)

    2003-01-01

    textabstractFive somatostatin receptor (sst) subtype genes, sst(1), sst(2), sst(3), sst(4) and sst(5), have been cloned and characterised. The five sst subtypes all bind natural somatostatin-14 and somatostatin-28 with high affinity. Endocrine pancreatic and endocrine digestive

  11. Evolutionary history of the somatostatin and somatostatin receptors

    Indian Academy of Sciences (India)

    Table 1. The identified somatostations. Somatostatin (SST1). Name. Scientific name. Length. High ID (to). Low ID (to) Chromosome. GS. Drs. Danio rerio. 324. 48.1 mms ...... ancestral source. References. Baranowska B., Chmielowska M., Wolinska-Witort E., Bik W.,. Baranowska-Bik A. and Martynska L. 2006 Direct effect of.

  12. Somatostatin receptor imaging in intracranial tumours

    International Nuclear Information System (INIS)

    Schmidt, M.; Scheidhauer, K.; Voth, E.; Schicha, H.; Luyken, C.; Hildebrandt, G.; Klug, N.

    1998-01-01

    The somatostatin analogue [ 111 In-DTPA-d-Phe 1 ]-octreotide ( 111 In-octreotide) allows scintigraphic visualization of somatostatin receptor-expressing tissue. While it is well known that a large variety of tissues express somatostatin receptors and 111 In-octreotide scintigraphy has a clearly defined role in various neuroendocrine diseases, the clinical value of 111 In-octreotide scintigraphy in brain tumours is still under clinical investigation. In 124 patients with 141 brain lesions (63 meningiomas, 24 pituitary adenomas, 10 gliomas WHO class I and II, 12 gliomas WHO class III and IV, 11 neurinomas and 2 neurofibromas, 7 metastases and 12 other varieties: three non-Hodgkin B-cell lymphomas, two epidermoids, one abscess, one angioleiomyoma, one chordoma, one haemangiopericytoma, one osteosarcoma, one plasmacytoma and one pseudocyst), 111 In-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 110-220 MBq 111 In-octreotide. Planar images of the head in four views with a 128 x 128 matrix and single-photon emission tomographic images (64 x 64 matrix) were acquired, and lesions were graded according to qualitative tracer uptake. Fifty-nine of the 63 meningiomas showed moderate to intense tracer uptake. Nine of 24 pituitary adenomas were visible; the remaining 15 did not show any tracer uptake. None of the class I and II gliomas with an intact blood-brain barrier were detected whereas 11/12 class III and IV gliomas showed 111 In-octreotide uptake. None of the neurinomas or neurofibromas were positive. Five of seven metastases were classified as positive, as were the osteosarcoma, two of three non-Hodgkin B-cell lymphomas, one abscess, one angioleiomyoma, one chordoma and one haemangiopericytoma. The other varieties (one non-Hodgkin B-cell lymphoma, two epidermoids, one plasmacytoma and one pseudocyst) did not show 111 In-octreotide uptake. The results demonstrate that a large variety of intracranial lesions express somatostatin receptors and

  13. Somatostatin receptor imaging in intracranial tumours

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, M.; Scheidhauer, K.; Voth, E.; Schicha, H. [Department of Nuclear Medicine, University of Koeln (Germany); Luyken, C.; Hildebrandt, G.; Klug, N. [Department of Neurosurgery, University of Kolen (Germany)

    1998-07-01

    The somatostatin analogue [{sup 111}In-DTPA-d-Phe{sup 1}]-octreotide ({sup 111}In-octreotide) allows scintigraphic visualization of somatostatin receptor-expressing tissue. While it is well known that a large variety of tissues express somatostatin receptors and {sup 111}In-octreotide scintigraphy has a clearly defined role in various neuroendocrine diseases, the clinical value of {sup 111}In-octreotide scintigraphy in brain tumours is still under clinical investigation. In 124 patients with 141 brain lesions (63 meningiomas, 24 pituitary adenomas, 10 gliomas WHO class I and II, 12 gliomas WHO class III and IV, 11 neurinomas and 2 neurofibromas, 7 metastases and 12 other varieties: three non-Hodgkin B-cell lymphomas, two epidermoids, one abscess, one angioleiomyoma, one chordoma, one haemangiopericytoma, one osteosarcoma, one plasmacytoma and one pseudocyst), {sup 111}In-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 110-220 MBq {sup 111}In-octreotide. Planar images of the head in four views with a 128 x 128 matrix and single-photon emission tomographic images (64 x 64 matrix) were acquired, and lesions were graded according to qualitative tracer uptake. Fifty-nine of the 63 meningiomas showed moderate to intense tracer uptake. Nine of 24 pituitary adenomas were visible; the remaining 15 did not show any tracer uptake. None of the class I and II gliomas with an intact blood-brain barrier were detected whereas 11/12 class III and IV gliomas showed {sup 111}In-octreotide uptake. None of the neurinomas or neurofibromas were positive. Five of seven metastases were classified as positive, as were the osteosarcoma, two of three non-Hodgkin B-cell lymphomas, one abscess, one angioleiomyoma, one chordoma and one haemangiopericytoma. The other varieties (one non-Hodgkin B-cell lymphoma, two epidermoids, one plasmacytoma and one pseudocyst) did not show {sup 111}In-octreotide uptake. The results demonstrate that a large variety of intracranial

  14. Somatostatin receptor scintigraphy on thyroid carcinoma

    International Nuclear Information System (INIS)

    Pan Weimin; Tan Tianzhi

    2004-01-01

    Purpose: To study the diagnostic value and clinical method of somatostatin receptor scintigraphy on thyroid carcinoma using 99 Tc m -RC-160 labeled with direct method as scintigraphy reagent; Methods: Somatostatin receptor scintigraphy (SRS) were performed on 25 patients with thyroid carcinoma, using 99 Tc m -RC-160 labeled with direct method as scintigraphy reagent, controlling with 131 I- whole- body- imaging(1312 -WBI). Results: Of 4 patients with MTC (medullary thyroid carcinoma), positive metastasis and primary tumour were detected on 3 patients by SRS, negative results were obtained by 131 I-WBI, the positive detective rate by SRS is 3/4; of 12 patients with PTC (papillary thyroid carcinoma), positive metastasis and primary tumour were detected on 2 patients by SRS or 131 I-WBI,1 of which only by SRS, while negative results were obtained by 131 I- WBI, the positive detective rate by SRS is 3/12; of 8 patients with FTC(follicular thyroid carcinoma), positive metastasis and primary tumour were detected on 1 patients by SRS or 131 I-WBI, and 2 positive results were obtained only by SRS, while negative by 131 I-WBI, the positive detective rate by SRS is 3/8; of 1 patients with HCC (hurthle cell carcinoma ), positive metastasis and primary tumour were detected by SRS, while negative by 131 I-WBI; Conclusions: SRS using 99 Tc m -RC-160 labeled with direct method as scintigraphy reagent has high diagnostic value on thyroid carcinoma, especially on MTC and HCC. (authors)

  15. Novel Somatostatin Receptor Ligands Therapies for Acromegaly

    Directory of Open Access Journals (Sweden)

    Rosa Maria Paragliola

    2018-03-01

    Full Text Available Surgery is considered the treatment of choice in acromegaly, but patients with persistent disease after surgery or in whom surgery cannot be considered require medical therapy. Somatostatin receptor ligands (SRLs octreotide (OCT, lanreotide, and the more recently approved pasireotide, characterized by a broader receptor ligand binding profile, are considered the mainstay in the medical management of acromegaly. However, in the attempt to offer a more efficacious and better tolerated medical approach, recent research has been aimed to override some limitations related to the use of currently approved drugs and novel SRLs therapies, with potential attractive features, have been proposed. These include both new formulation of older molecules and new molecules. Novel OCT formulations are aimed in particular to improve patients’ compliance and to reduce injection discomfort. They include an investigational ready-to-use subcutaneous depot OCT formulation (CAM2029, delivered via prefilled syringes and oral OCT that uses a “transient permeability enhancer” technology, which allows for OCT oral absorption. Another new delivery system is a long-lasting OCT implant (VP-003, which provide stable doses of OCT throughout a period of several months. Finally, a new SRL DG3173 (somatoprim seems to be more selective for GH secretion, suggesting possible advantages in the presence of hyperglycemia or diabetes. How much these innovations will actually be beneficial to acromegaly patients in real clinical practice remains to be seen.

  16. Immunohistochemical detection of somatostatin receptor subtypes sst1 and sst2A in human somatostatin receptor positive tumors

    NARCIS (Netherlands)

    L.J. Hofland (Leo); Q. Liu; P.M. van Koetsveld (Peter); J. Zuijderwijk; F. van der Ham (Frieda); R.R. de Krijger (Ronald); A. Schonbrunn; S.W.J. Lamberts (Steven)

    1999-01-01

    textabstractAlthough in situ hybridization has been used to examine the distribution of messenger RNA for somatostatin receptor subtypes (sst) in human tumors, the cellular localization of sst1 and sst2A receptors has not been reported. In this study, we describe the

  17. Development of 99mTc labelled somatostatin analogues with high affinity for somatostatin receptors

    International Nuclear Information System (INIS)

    Maina, T.; Nock, B.; Nicolopoulou, A.; Tsipra, C.; Poppe, M.; Chiotellis, E.

    2001-01-01

    A recent development in oncology involves the use of metabolically stabilized peptide hormone analogues labelled with metallic radionuclides for the diagnosis or therapy of malignant disease. This approach was successfully applied for the first time in the visualization of somatostatin positive tumours and their metastases with 111 In DTPA-octreotide. In an effort to obtain a 99m Tc somatostatin receptor affine radioligand we describe herein the synthesis, radiochemistry and preliminary biological evaluation of two novel 99m Tc labelled somatostatin analogues, N 4 -TOC and N 4 -RC-160. In these compounds a tetraamine bifunctional unit was covalently attached to the N-terminal (D)Phe 1 of the peptide chain using Boc-protection strategies. The peptide conjugates were purified by high performance liquid chromatography (HPLC) and characterized by UV/Vis and ES-MS spectroscopies. As revealed by HPLC, 99m Tc labelling was quantitative under mild conditions, leading to a single 99m Tc species in high specific activities. Affinity of 99m Tc N 4 -TOC for the somatostatin receptor, as determined by in vitro binding assays in rat brain cortex membranes, was found unaffected by the presence of the bulky metal chelate. The binding properties of 99m Tc N 4 -RC-160 could not be determined by this assay due to an extremely high non-specific binding of this radioligand, and will be shortly investigated by other methods. Tissue distribution in healthy mice revealed that 99m Tc N 4 -TOC is clearing mainly through the kidneys and the urinary tract whereas 99m Tc N 4 -RC-160 shows a high accumulation in the liver as a result of its lipophilicity. Analysis of urine samples by HPLC showed that 99m Tc N 4 -TOC is excreted integer from the body of mice, while 99m Tc N 4 -RC-160 is totally transformed to an unidentified hydrophilic metabolite in vivo. The location of this metabolism is currently investigated. In vivo blocking experiments using animals pre-treated with 50 μg octreotide

  18. Somatostatin receptor scintigraphy in patients with cat-scratch disease

    International Nuclear Information System (INIS)

    Krause, R.; Schnedl, W.J.; Hoier, S.; Piswanger-Soelkner, C.; Lipp, R.W.; Daxboeck, F.; Reisinger, E.C.

    2006-01-01

    Aim: somatostatin receptor scintigraphy images various neoplastic, granulomatous, and auto-immun diseases. Cat-scratch disease in an infectious granulomatous disease usually affecting the lymphnodes. It is not known whether cat-scratch disease provides positive somatostatin receptor scintigrams. Patients, methods: twelve patients with lymphadenitis and suspected cat-scratch disease were investigated by immunofluorescence antibody testing and somatostatin receptor scintigraphy. Suppurated lymphnodes were extracted or drained and Bartonella henselae specific PCR was then performed. Results: eleven of 12 patients showed IgG antibodies against B. henselea. SRS showed positive scintigraphic results in 6 of 11 patients with CSD. B. henselae DNA was detected in tissue of lymphnodes from 4 of 5 patients with lymphnode extraction or lymphnode drainage. SRS demonstrated positive scintigrams in all patients with a positive PCR. In one patient with suspected CSD SRS was negative as well as antibody testing. Conclusion: somatostatin receptor scintigraphy correlated with positive Bartonella henselae specific PCR tests and positive Bartonella henselae specific antibody tests in patients with CSD. (orig.)

  19. Somatostatin receptor scintigraphy in patients with cat-scratch disease

    Energy Technology Data Exchange (ETDEWEB)

    Krause, R.; Schnedl, W.J.; Hoier, S. [Div. of Infectious Diseases, Dept. of Internal Medicine, Univ. Graz (Austria); Piswanger-Soelkner, C.; Lipp, R.W. [Div. of Nuclear Medicine, Dept. of Internal Medicine, Univ. Graz (Austria); Daxboeck, F. [Clinical Inst. for Hygiene and Medical Microbiology, Div. of Hospital Hygiene, Univ. of Vienna (Austria); Reisinger, E.C. [Div. of Infectious Diseases and Tropical Medicine, Dept. of Internal Medicine, Univ. Rostock (Germany)

    2006-07-01

    Aim: somatostatin receptor scintigraphy images various neoplastic, granulomatous, and auto-immun diseases. Cat-scratch disease in an infectious granulomatous disease usually affecting the lymphnodes. It is not known whether cat-scratch disease provides positive somatostatin receptor scintigrams. Patients, methods: twelve patients with lymphadenitis and suspected cat-scratch disease were investigated by immunofluorescence antibody testing and somatostatin receptor scintigraphy. Suppurated lymphnodes were extracted or drained and Bartonella henselae specific PCR was then performed. Results: eleven of 12 patients showed IgG antibodies against B. henselea. SRS showed positive scintigraphic results in 6 of 11 patients with CSD. B. henselae DNA was detected in tissue of lymphnodes from 4 of 5 patients with lymphnode extraction or lymphnode drainage. SRS demonstrated positive scintigrams in all patients with a positive PCR. In one patient with suspected CSD SRS was negative as well as antibody testing. Conclusion: somatostatin receptor scintigraphy correlated with positive Bartonella henselae specific PCR tests and positive Bartonella henselae specific antibody tests in patients with CSD. (orig.)

  20. Somatostatin receptor-mediated imaging and therapy: basic science, current knowledge, limitations and future perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Breeman, W.A.P.; Jong, M. de; Kwekkeboom, D.J.; Valkema, R.; Bakker, W.H.; Kooij, P.P.M. [Dept. of Nuclear Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Visser, T.J. [Dept. of Internal Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Krenning, E.P. [Dept. of Nuclear Medicine, Erasmus Medical Centre Rotterdam (Netherlands); Dept. of Internal Medicine, Erasmus Medical Centre Rotterdam (Netherlands)

    2001-09-01

    In vivo somatostatin receptor-mediated scintigraphy has proven to be a valuable method for the visualisation of neuroendocrine tumours and their metastases. A new application is the use of radiolabelled analogues for somatostatin receptor-mediated therapy. This paper presents a review on the basic science, historical background and current knowledge of somatostatin receptor subtypes and their expression in neuroendocrine tumours. New somatostatin analogues, new chelators, ''new'' radionuclides and combinations thereof are also discussed. Due attention is given to limitations and future perspectives of somatostatin receptor-mediated imaging and therapy. (orig.)

  1. Somatostatin receptor-mediated imaging and therapy: basic science, current knowledge, limitations and future perspectives

    International Nuclear Information System (INIS)

    Breeman, W.A.P.; Jong, M. de; Kwekkeboom, D.J.; Valkema, R.; Bakker, W.H.; Kooij, P.P.M.; Visser, T.J.; Krenning, E.P.

    2001-01-01

    In vivo somatostatin receptor-mediated scintigraphy has proven to be a valuable method for the visualisation of neuroendocrine tumours and their metastases. A new application is the use of radiolabelled analogues for somatostatin receptor-mediated therapy. This paper presents a review on the basic science, historical background and current knowledge of somatostatin receptor subtypes and their expression in neuroendocrine tumours. New somatostatin analogues, new chelators, ''new'' radionuclides and combinations thereof are also discussed. Due attention is given to limitations and future perspectives of somatostatin receptor-mediated imaging and therapy. (orig.)

  2. Activation of somatostatin 2 receptors in the brain and the periphery induces opposite changes in circulating ghrelin levels: functional implications

    Directory of Open Access Journals (Sweden)

    Andreas eStengel

    2013-01-01

    Full Text Available Somatostatin is an important modulator of neurotransmission in the central nervous system and acts as a potent inhibitor of hormone and exocrine secretion and regulator of cell proliferation in the periphery. These pleiotropic actions occur through interaction with five G-protein coupled somatostatin receptor subtypes (sst1-5 that are widely expressed in the brain and peripheral organs. The characterization of somatostatin’s effects can be investigated by pharmacological or genetic approaches using newly developed selective sst agonists and antagonists and mice lacking specific sst subtypes. Recent evidence points towards a divergent action of somatostatin in the brain and in the periphery to regulate circulating levels of ghrelin, an orexigenic hormone produced by the endocrine X/A-like cells in the gastric mucosa. Somatostatin interacts with the sst2 in the brain to induce an increase in basal ghrelin plasma levels and counteracts the visceral stress-related decrease in circulating ghrelin in rats. By contrast, stimulation of peripheral somatostatin-sst2 signaling results in the inhibition of basal ghrelin release and mediates the postoperative decrease in circulating ghrelin in rats. The peripheral sst2-mediated reduction of plasma ghrelin is likely to involve a paracrine action of D-cell derived somatostatin acting on sst2 bearing X/A-like ghrelin cells in the gastric mucosa. The other member of the somatostatin family, named cortistatin, in addition to binding to sst1-5 also directly interacts with the ghrelin receptor and therefore may simultaneously modulate ghrelin release and actions at target sites bearing ghrelin receptors representing a link between the ghrelin and somatostatin systems.

  3. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    Energy Technology Data Exchange (ETDEWEB)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de [Erasmus MC, Department of Nuclear Medicine, V 220, Rotterdam (Netherlands); Boerman, Otto C. [Radboud University Hospital, Department of Nuclear Medicine, Nijmegen (Netherlands)

    2010-05-15

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  4. Kidney protection during peptide receptor radionuclide therapy with somatostatin analogues

    International Nuclear Information System (INIS)

    Rolleman, Edgar J.; Melis, Marleen; Valkema, Roelf; Krenning, Eric P.; Jong, Marion de; Boerman, Otto C.

    2010-01-01

    This review focuses on the present status of kidney protection during peptide receptor radionuclide therapy (PRRT) using radiolabelled somatostatin analogues. This treatment modality for somatostatin receptor-positive tumours is limited by renal reabsorption and retention of radiolabelled peptides resulting in dose-limiting high kidney radiation doses. Radiation nephropathy has been described in several patients. Studies on the mechanism and localization demonstrate that renal uptake of radiolabelled somatostatin analogues largely depends on the megalin/cubulin system in the proximal tubule cells. Thus methods are needed that interfere with this reabsorption pathway to achieve kidney protection. Such methods include coadministration of basic amino acids, the bovine gelatin-containing solution Gelofusine or albumin fragments. Amino acids are already commonly used in the clinical setting during PRRT. Other compounds that interfere with renal reabsorption capacity (maleic acid and colchicine) are not suitable for clinical use because of potential toxicity. The safe limit for the renal radiation dose during PRRT is not exactly known. Dosimetry studies applying the principle of the biological equivalent dose (correcting for the effect of dose fractionation) suggest that a dose of about 37 Gy is the threshold for development of kidney toxicity. This threshold is lower when risk factors for development of renal damage exist: age over 60 years, hypertension, diabetes mellitus and previous chemotherapy. A still experimental pathway for kidney protection is mitigation of radiation effects, possibly achievable by cotreatment with amifostine (Ethylol), a radiation protector, or with blockers of the renin-angiotensin-aldosterone system. Future perspectives on improving kidney protection during PRRT include combinations of agents to reduce renal retention of radiolabelled peptides, eventually together with mitigating medicines. Moreover, new somatostatin analogues with lower

  5. Somatostatin: a metabolic regulator

    International Nuclear Information System (INIS)

    Dileepan, K.N.; Wagle, S.R.

    1985-01-01

    Somatostatin, the hypothalamic release-inhibiting factor, has been found to stimulate gluconeogenesis in rat kidney cortical slices. Stimulation by somatostatin was linear and dose-dependent. Other bioactive peptides such as cholecystokinin, gastro-intestinal peptide, secretin, neurotensin, vasoactive intestinal peptide, pancreatic polypeptide, beta endorphin and substance P did not affect the renal gluconeogenic activity. Somatostatin-induced gluconeogenesis was blocked by phentolamine (alpha adrenergic antagonist) and prazosin (alpha 1 adrenergic antagonist) but not by propranolol (beta adrenergic antagonist) and yohimbine (alpha 2 adrenergic antagonist) suggesting that the effect is via alpha 1 adrenergic stimuli. Studies on the involvement of Ca 2+ revealed that tissue depletion and omission of Ca 2+ from the reaction mixture would abolish the stimulatory effect of somatostatin. Furthermore, somatostatin enhanced the uptake of 45 calcium in renal cortical slices which could be blocked by lanthanum, an inhibitor of Ca 2+ influx. It is proposed that the stimulatory effect of somatostatin on renal gluconeogenesis is mediated by alpha 1 adrenergic receptors, or those which functionally resemble the alpha 1 receptors and that the increased influx of Ca 2+ may be the causative factor for carrying out the stimulus. 88 references

  6. Somatostatin: a metabolic regulator

    Energy Technology Data Exchange (ETDEWEB)

    Dileepan, K.N.; Wagle, S.R.

    1985-12-23

    Somatostatin, the hypothalamic release-inhibiting factor, has been found to stimulate gluconeogenesis in rat kidney cortical slices. Stimulation by somatostatin was linear and dose-dependent. Other bioactive peptides such as cholecystokinin, gastro-intestinal peptide, secretin, neurotensin, vasoactive intestinal peptide, pancreatic polypeptide, beta endorphin and substance P did not affect the renal gluconeogenic activity. Somatostatin-induced gluconeogenesis was blocked by phentolamine (alpha adrenergic antagonist) and prazosin (alpha/sub 1/ adrenergic antagonist) but not by propranolol (beta adrenergic antagonist) and yohimbine (alpha/sub 2/ adrenergic antagonist) suggesting that the effect is via alpha/sub 1/ adrenergic stimuli. Studies on the involvement of Ca/sup 2 +/ revealed that tissue depletion and omission of Ca/sup 2 +/ from the reaction mixture would abolish the stimulatory effect of somatostatin. Furthermore, somatostatin enhanced the uptake of /sup 45/calcium in renal cortical slices which could be blocked by lanthanum, an inhibitor of Ca/sup 2 +/ influx. It is proposed that the stimulatory effect of somatostatin on renal gluconeogenesis is mediated by alpha/sub 1/ adrenergic receptors, or those which functionally resemble the alpha/sub 1/ receptors and that the increased influx of Ca/sup 2 +/ may be the causative factor for carrying out the stimulus. 88 references.

  7. Reduced Numbers of Somatostatin Receptors in the Cerebral Cortex in Alzheimer's Disease

    Science.gov (United States)

    Flint Beal, M.; Mazurek, Michael F.; Tran, Vinh T.; Chattha, Geetinder; Bird, Edward D.; Martin, Joseph B.

    1985-07-01

    Somatostatin receptor concentrations were measured in patients with Alzheimer's disease and controls. In the frontal cortex (Brodmann areas 6, 9, and 10) and temporal cortex (Brodmann area 21), the concentrations of somatostatin in receptors in the patients were reduced to approximately 50 percent of control values. A 40 percent reduction was seen in the hippocampus, while no significant changes were found in the cingulate cortex, postcentral gyrus, temporal pole, and superior temporal gyrus. Scatchard analysis showed a reduction in receptor number rather than a change in affinity. Somatostatin-like immunoreactivity was significantly reduced in both the frontal and temporal cortex. Somatostatin-like immunoreactivity was linearly related to somatostatin-receptor binding in the cortices of Alzheimer's patients. These findings may reflect degeneration of postsynaptic neurons or cortical afferents in the patients' cerebral cortices. Alternatively, decreased somatostatinlike immunoreactivity in Alzheimer's disease might indicate increased release of somatostatin and down regulation of postsynaptic receptors.

  8. Somatostatin-receptor imaging in the localization of endocrine tumors

    International Nuclear Information System (INIS)

    Lamberts, S.W.; Bakker, W.H.; Reubi, J.C.; Krenning, E.P.

    1990-01-01

    A number of different tumors have receptors for somatostatin. We evaluated the efficacy of scanning with 123 I-labeled Tyr3-octreotide, a somatostatin analogue, for tumor localization in 42 patients with carcinoid tumors, pancreatic endocrine tumors, or paragangliomas. We then evaluated the response to octreotide therapy in some of these patients. Primary tumors or metastases, often previously unrecognized, were visualized in 12 of 13 patients with carcinoid tumors and in 7 of 9 patients with pancreatic endocrine tumors. The endocrine symptoms of these patients responded well to therapy with octreotide. Among 20 patients with paragangliomas, 8 of whom had more than one tumor, 10 temporal (tympanic or jugular), 9 carotid, and 10 vagal tumors could be visualized. One small tympanic tumor and one small carotid tumor were not seen on the scan. The 123 I-labeled Tyr3-octreotide scanning technique is a rapid and safe procedure for the visualization of some tumors with somatostatin receptors. A positive scan may predict the ability of octreotide therapy to control symptoms of hormonal hypersecretion

  9. Somatostatin receptor subtype expression in human thyroid tumours.

    Science.gov (United States)

    Klagge, A; Krause, K; Schierle, K; Steinert, F; Dralle, H; Fuhrer, D

    2010-04-01

    Somatostatin receptors (SSTR) are expressed in various endocrine tumours. The expression of SSTR at the tumour cell surface confers the possibility for diagnostic imaging and therapy of tumours using radiolabeled somatostatin analogues. The majority of currently available somatostatin analogues show a higher binding affinity for the SSTR2 subtype. To date, the precise expression pattern of the SSTR subtypes 1-5 in thyroid epithelial tumours remains to be determined. We investigated the mRNA expression of SSTR1-5 in benign and malignant epithelial thyroid tumours [20 cold thyroid nodules (CTNs), 20 toxic thyroid nodules (TTNs), 20 papillary, 20 follicular, and 5 anaplastic carcinomas (PTCs, FTCs, ATCs, respectively)] and compared them to normal surrounding thyroid tissues. Four out of five SSTR subtypes were detected in malignant thyroid tumours, benign neoplasia, and normal surrounding tissue with a predominant expression of SSTR2 and SSTR5, and a weak expression of SSTR1 and SSTR3. Weak SSTR4 mRNA expression was detected in some PTCs. Compared to normal thyroid tissue, SSTR2 was significantly upregulated in PTC and ATC. In addition significant upregulation of SSTR3 was found in PTC. SSTR5 mRNA expression was increased in PTC and FTC and significantly decreased in CTN and TTN compared to normal thyroid tissue. SSTR2 is the predominant subtype in thyroid epithelial tumours with a high expression pattern, in particular, in PTC . Perspectively, the expression of distinct SSTR in thyroid epithelial tumours might represent a promising avenue for diagnostics and therapy of advanced thyroid cancer with somatostatin analogues. Georg Thieme Verlag KG Stuttgart New York.

  10. Somatostatin receptor scintigraphy in endocrine ophthalmopathy; Somatostatin-Rezeptor-Szintigraphie bei endokriner Orbitopathie

    Energy Technology Data Exchange (ETDEWEB)

    Diaz, M. [Klinik und Poliklinik fuer Nuklearmedizin, Univ. Mainz (Germany); Kahaly, G. [3. Medizinische Klinik und Poliklinik, Innere Medizin - Endokrinologie, Univ. Mainz (Germany); Muehlbach, A. [3. Medizinische Klinik und Poliklinik, Innere Medizin - Endokrinologie, Univ. Mainz (Germany); Bockisch, A. [Klinik und Poliklinik fuer Nuklearmedizin, Univ. Mainz (Germany); Beyer, J. [3. Medizinische Klinik und Poliklinik, Innere Medizin - Endokrinologie, Univ. Mainz (Germany); Hahn, K. [Klinik und Poliklinik fuer Nuklearmedizin, Univ. Mainz (Germany)

    1994-12-01

    Somatostatin receptor scintigraphy with {sup 111}In-labeled octreotide proves to be a very sensitive diagnostic tool for evaluation of inflammative activity in endocrine ophthalmopathy (EO). The results of somatostatin receptor scintigraphy (SRS) in 40 patients with EO show a high orbital accumulation of {sup 111}In-octreotide in clinically active EO (4h-median/orbit-brain-ratio: 12.6; controls 4h-median: 5.8) Patients with clinically inactive EO (4h-median: 7.1) show a similar orbital accumulation of radioactivity compared to controls. 5 patients with active orbital myositis also revealed an even higher orbital accumulation of radioactivity (4h-median: 42.3). The diagnostic value of SRS lies in its ability to act as a measure of inflammation and an be useful as an activity parameter when planning therapeutic procedure as well as for EO follow-up. The results in patients with orbital myositis nevertheless do not permit a differential diagnosis with this method. The therapeutic value of {sup 111}In-octreotide in Graves` disease has yet to be established. (orig.) [Deutsch] Die Somatostatin-Rezeptor-Szintigraphie (SRS) mit dem {sup 111}Indium-markierten Somatostatinanalogon Octreotid stellt ein sensitives Verfahren zur Einschaetzung der entzuendlichen Aktivitaet bei endokriner Orbitopathie (EO) dar. Die Untersuchungen an 40 Patienten mit EO ergaben eine im Vergleich zur Kontrollgruppe signifikant hoehere orbitale Octreotidanreicherung bei klinisch aktiver Erkrankung (4h-Median/Orbita-Hirn-Quotient: 12,6; Kontrollgruppe 4h-Median: 5,8; p=0,0032). Patienten mit klinisch nicht aktiver Erkrankung (4h-Median: 7,1) unterschieden sich bezueglich der orbitalen Octreotidanreicherung nicht wesentlich von der Kontrollgruppe. Auch 5 Patienten mit florider orbitaler Myositis zeigten eine deutlich gesteigerte orbitale Aktivitaetsanreicherung (4h-Median: 42,3). Der diagnostische Nutzen der SRS liegt somit in ihrer Eigenschaft als Aktivitaets- und Entzuendungsparameter und kann mit

  11. Development of antibodies against the rat brain somatostatin receptor.

    Science.gov (United States)

    Theveniau, M; Rens-Domiano, S; Law, S F; Rougon, G; Reisine, T

    1992-05-15

    Somatostatin (SRIF) is a neurotransmitter in the brain involved in the regulation of motor activity and cognition. It induces its physiological actions by interacting with receptors. We have developed antibodies against the receptor to investigate its structural properties. Rabbit polyclonal antibodies were generated against the rat brain SRIF receptor. These antibodies (F4) were able to immunoprecipitate solubilized SRIF receptors from rat brain and the cell line AtT-20. The specificity of the interaction of these antibodies with SRIF receptors was further demonstrated by immunoblotting. F4 detected SRIF receptors of 60 kDa from rat brain and adrenal cortex and the cell lines AtT-20, GH3, and NG-108, which express high densities of SRIF receptors. They did not detect immunoreactive material from rat liver or COS-1, HEPG, or CRL cells, which do not express functional SRIF receptors. In rat brain, 60-kDa immunoreactivity was detected by F4 in the hippocampus, cerebral cortex, and striatum, which have high densities of SRIF receptors. However, F4 did not interact with proteins from cerebellum and brain stem, which express few SRIF receptors. Immunoreactive material cannot be detected in rat pancreas or pituitary, which have been reported to express a 90-kDa SRIF receptor subtype. The selective detection of 60-kDa SRIF receptors by F4 indicates that the 60- and 90-kDa SRIF receptor subtypes are immunologically distinct. The availability of antibodies that selectively detect native and denatured brain SRIF receptors provides us with a feasible approach to clone the brain SRIF receptor gene(s).

  12. Physiologic basics and clinical experience with somatostatin-receptor-scintigraphy

    International Nuclear Information System (INIS)

    Henze, E.; Eberhardt, J.U.; Bohuslavizki, K.H.

    1994-01-01

    The introduction of radiolabelled octreotide, an analogon to the receptor binding hormone Somatostatin, has markedly increased the ability to detect structures and tumours carrying somatostatin receptors by nuclear medicine imaging with high sensitivity and specificity. It has been shown that in vitro receptor density and in vivo scintigraphic results correlate well in particular in tumours of neuroendocrine origin of the GI tract such as insulinomas, gastrinomas, glucagonomas, carcionoids, but also in paragangliomas, small cell lung cancer and meningiomas. As receptors were also shown to be present on so called activated leucocytes granulomas, lymphomas and autoimmune disease have been imaged with octreotide successfully. The specific tracer (In-111-DTPA-D-PHE-Octreotide, Octreoscan R ) is rapidly cleared from the blood pool by the kidneys and, partially, via the liver providing a high target to background ratio. Physiologic uptake is usually observed in the pituitary and thyroid glands, in spleen and liver. Optimum tracer accumulation for tumour scintigraphy is seen on the 24-h-images with the best target to background ratios. Additional SPECT-imaging is recommended in particular in the abdominal regions. The sensitivity in imaging the above named tumours ranges from 70 up to 100%. In-111 octreotide imaging is of diagnostic impact both for the primary diagnostic evaluation as well as for detecting or excluding secondary manifestations in known tumour sites. Of specific value is the information on relative receptor density in the tumour to be treated as may be obtained by quantitative In-111 octreotide imaging for decision making whether or not to use cold octreotide (Sandostatin R ) as a receptor blocking drug for therapy as well as for treatment follow-up studies. (author)

  13. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  14. Somatostatin receptors in rat hippocampus: localization to intrinsic neurons

    International Nuclear Information System (INIS)

    Palacios, J.M.; Reubi, J.C.; Maurer, R.

    1986-01-01

    The effect of neurotoxic chemical and electrolytical lesions on somatostatin (SS) receptor binding in the septo-hippocampal afferents, pyramidal and granule cells of the rat hippocampus was examined by autoradiography using the stable SS analogue 125 I-204-090 as radioligand. Electrolytical lesions of the septum did not result in modification of SS binding in the hippocampus. In contrast, both granule cell lesion with colchicine and pyramidal or pyramidal and granule cell lesions with increasing kainic acid doses did result in a specific decrease of binding in the dentate gyrus and hippocampus (CA 1 and CA 3 ). These results suggest that SS receptors in the hippocampus are probably associated with elements from intrinsic neurons. (Author)

  15. Validation of somatostatin receptor scintigraphy in the localization of neuroendocrine tumors

    International Nuclear Information System (INIS)

    Lamberts, S.W.J.; Reubi, J.C.; Krenning, E.P.

    1993-01-01

    Somatostatin analogs are used in the control of hormonal hypersecretion and tumor growth of patients with acromegaly, islet cell carcinomas and carcinoids. Recently we showed that somatostatin receptor positive tumors can be visualized in vivo after the administration of radionuclide-labeled somatostatin analogs. Receptor imaging was positive in 18/21 islet cell tumors, 32/37 carcinoids, 26/28 paragangliomas, 9/14 medullary thyroid carcinomas, and 5/7 small cell lung cancers. Somatostatin receptor imaging is an easy, harmless and painless diagnostic method. It localizes multiple and/or metastatic tumors, predicts the successful control of hormonal hypersecretion by octreotide and seems to be of prognostic value in certain types of cancer. This scintigraphic method might help in patient selection for clinical trials with somatostatin analogs in the treatment of neuroendocrine cancers. (orig.)

  16. Validation of somatostatin receptor scintigraphy in the localization of neuroendocrine tumors

    Energy Technology Data Exchange (ETDEWEB)

    Lamberts, S.W.J. (Depts. of Medicine and Nuclear Medicine, Erasmus Univ., Rotterdam (Netherlands) Div. of Cell Biology and Experimental Cancer Research, Institution of Pathology, Bern Univ. (Switzerland)); Reubi, J.C. (Depts. of Medicine and Nuclear Medicine, Erasmus Univ., Rotterdam (Netherlands) Div. of Cell Biology and Experimental Cancer Research, Institution of Pathology, Bern Univ. (Switzerland)); Krenning, E.P. (Depts. of Medicine and Nuclear Medicine, Erasmus Univ., Rotterdam (Netherlands) Div. of Cell Biology and Experimental Cancer Research, Institution of Pathology, Bern Univ. (Switzerland))

    1993-01-01

    Somatostatin analogs are used in the control of hormonal hypersecretion and tumor growth of patients with acromegaly, islet cell carcinomas and carcinoids. Recently we showed that somatostatin receptor positive tumors can be visualized in vivo after the administration of radionuclide-labeled somatostatin analogs. Receptor imaging was positive in 18/21 islet cell tumors, 32/37 carcinoids, 26/28 paragangliomas, 9/14 medullary thyroid carcinomas, and 5/7 small cell lung cancers. Somatostatin receptor imaging is an easy, harmless and painless diagnostic method. It localizes multiple and/or metastatic tumors, predicts the successful control of hormonal hypersecretion by octreotide and seems to be of prognostic value in certain types of cancer. This scintigraphic method might help in patient selection for clinical trials with somatostatin analogs in the treatment of neuroendocrine cancers. (orig.).

  17. Muscarinic Receptor Agonists and Antagonists

    Directory of Open Access Journals (Sweden)

    David R. Kelly

    2001-02-01

    Full Text Available A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes. Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.

  18. Truncated somatostatin receptor 5 may modulate therapy response to somatostatin analogues--Observations in two patients with acromegaly and severe headache

    DEFF Research Database (Denmark)

    Marina, Djordje; Burman, Pia; Klose, Marianne

    2015-01-01

    BACKGROUND: Somatotropinomas have unique "fingerprints" of somatostatin receptor (sst) expression, which are targets in treatment of acromegaly with somatostatin analogues (SSAs). However, a significant expression of sst is not always related to the biochemical response to SSAs. Headache is a com...

  19. Coupling of guanine nucleotide inhibitory protein to somatostatin receptors on pancreatic acinar membranes

    International Nuclear Information System (INIS)

    Sakamoto, C.; Matozaki, T.; Nagao, M.; Baba, S.

    1987-01-01

    Guanine nucleotides and pertussis toxin were used to investigate whether somatostatin receptors interact with the guanine nucleotide inhibitory protein (NI) on pancreatic acinar membranes in the rat. Guanine nucleotides reduced 125 I-[Tyr 1 ]somatostatin binding to acinar membranes up to 80%, with rank order of potency being 5'-guanylyl imidodiphosphate [Gpp(NH)p]>GTP>TDP>GMP. Scatchard analysis revealed that the decrease in somatostatin binding caused by Gpp(NH)p was due to the decrease in the maximum binding capacity without a significant change in the binding affinity. The inhibitory effect of Gpp(NH)p was partially abolished in the absence of Mg 2+ . When pancreatic acini were treated with 1 μg/ml pertussis toxin for 4 h, subsequent 125 I-[Tyr 1 ]somatostatin binding to acinar membranes was reduced. Pertussis toxin treatment also abolished the inhibitory effect of somatostatin on vasoactive intestinal peptide-stimulated increase in cellular content of adenosine 3',5'-cyclic monophosphate (cAMP) in the acini. The present results suggest that 1) somatostatin probably functions in the pancreas to regulate adenylate cyclase enzyme system via Ni, 2) the extent of modification of Ni is correlated with the ability of somatostatin to inhibit cAMP accumulation in acini, and 3) guanine nucleotides also inhibit somatostatin binding to its receptor

  20. Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

    Energy Technology Data Exchange (ETDEWEB)

    Waser, Beatrice; Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, PO Box 62, Berne (Switzerland)

    2014-06-15

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the {sup 125}iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer {sup 125}I-GLP-1(7-36)amide. Receptor autoradiography studies with {sup 125}I-GLP-1(7-36)amide agonist or {sup 125}I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist {sup 125}I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer {sup 125}I-GLP-1(7-36)amide. For comparison, {sup 125}I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with {sup 125}I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

  1. Radiolabelled GLP-1 receptor antagonist binds to GLP-1 receptor-expressing human tissues

    International Nuclear Information System (INIS)

    Waser, Beatrice; Reubi, Jean Claude

    2014-01-01

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. For the somatostatin receptor targeting of tumours, however, it was recently reported that antagonist tracers were superior to agonist tracers. The present study therefore evaluated various forms of the 125 iodinated-Bolton-Hunter (BH)-exendin(9-39) antagonist tracer for the in vitro visualization of GLP-1 receptor-expressing tissues in rats and humans and compared it with the agonist tracer 125 I-GLP-1(7-36)amide. Receptor autoradiography studies with 125 I-GLP-1(7-36)amide agonist or 125 I-BH-exendin(9-39) antagonist radioligands were performed in human and rat tissues. The antagonist 125 I-BH-exendin(9-39) labelled at lysine 19 identifies all human and rat GLP-1 target tissues and GLP-1 receptor-expressing tumours. Binding is of high affinity and is comparable in all tested tissues in its binding properties with the agonist tracer 125 I-GLP-1(7-36)amide. For comparison, 125 I-BH-exendin(9-39) with the BH labelled at lysine 4 did identify the GLP-1 receptor in rat tissues but not in human tissues. The GLP-1 receptor antagonist exendin(9-39) labelled with 125 I-BH at lysine 19 is an excellent GLP-1 radioligand that identifies human and rat GLP-1 receptors in normal and tumoural tissues. It may therefore be the molecular basis to develop suitable GLP-1 receptor antagonist radioligands for in vivo imaging of GLP-1 receptor-expressing tissues in patients. (orig.)

  2. Somatostatin receptor scintigraphy using (99m)Tc-EDDA/HYNIC-TOC in patients with medullary thyroid carcinoma

    NARCIS (Netherlands)

    Czepczynski, Rafal; Parisella, Maria Gemma; Kosowicz, Jerzy; Mikolajczak, Renata; Ziemnicka, Katarzyna; Gryczynska, Maria; Sowinski, Jerzy; Signore, Alberto

    2007-01-01

    Purpose Several new somatostatin analogues have been developed for the diagnosis and therapy of different tumours. Since somatostatin receptors are often over-expressed in medullary thyroid carcinoma (MTC), the aim of our study was to evaluate the utility of scintigraphy with the somatostatin

  3. Benzodiazepine receptor antagonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C

    2004-01-01

    Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition. Benzodiazepine receptor antagonists may have a beneficial effect on patients with hepatic encephalopathy....

  4. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

    Directory of Open Access Journals (Sweden)

    Andreas Stengel

    2017-04-01

    Full Text Available Corticotropin-releasing factor (CRF is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

  5. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response.

    Science.gov (United States)

    Stengel, Andreas; Taché, Yvette F

    2017-01-01

    Corticotropin-releasing factor (CRF) is the hallmark brain peptide triggering the response to stress and mediates-in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA) axis-other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a broader anti-stress effect by blunting the endocrine, autonomic, behavioral (with a focus on food intake) and visceral gastrointestinal motor responses through the involvement of distinct somatostatin receptor subtypes.

  6. GABAA receptor partial agonists and antagonists

    DEFF Research Database (Denmark)

    Krall, Jacob; Balle, Thomas; Krogsgaard-Larsen, Niels

    2015-01-01

    to the local temporal pattern of GABA impact, enabling phasic or tonic inhibition. Specific GABAAR antagonists are essential tools for physiological and pharmacological elucidation of the different type of GABAAR inhibition. However, distinct selectivity among the receptor subtypes (populations) has been shown...... antagonists have been essential in defining the tonic current but both remaining issues concerning the GABAARs involved and the therapeutic possibilities of modulating tonic inhibition underline the need for GABAAR antagonists with improved selectivity....

  7. Somatostatin Receptor Scintigraphy Findings in a Patient with Metastatic Gastrinoma and MEN 1 Syndrome

    Directory of Open Access Journals (Sweden)

    Gözde Mütevelizade

    2011-12-01

    Full Text Available Liver metastases from neuroendocrine tumours frequently occur and significantly worsen their prognosis. Somatostatin receptor scintigraphy (SRS is a valuable method for the detection of somatostatin receptor-positive lesions like gastrinoma. In this case report, the importance of SRS to localize the primary tumor and the spread of disease is emphasized in a patient with neuroendocrine liver metastases. A 45-year-old man was admitted to hospital with multiple liver metastasis of neuroendocrine carcinoma. Somatostatin receptor scintigraphy showed multiple intense radiotracer uptakes in the liver and a focal tracer uptake at the right side of the upper abdominal region corresponding to duodenum or pancreas. Elevated serum gastrin levels confirmed the gastrinoma diagnosis. (MRT 2011;20:117-120

  8. NMDAR hypofunction and somatostatin-expressing GABAergic interneurons and receptors: A newly identified correlation and its effects in schizophrenia

    Directory of Open Access Journals (Sweden)

    Fatemah Alherz

    2017-06-01

    Full Text Available This review investigates the association between N-methyl-d-Aspartate receptor (NMDAR hypofunction and somatostatin-expressing GABAergic interneurons (SST+ and how it contributes to the cognitive deficits observed in schizophrenia (SZ. This is based on evidence that NMDAR antagonists caused symptoms resembling SZ in healthy individuals. NMDAR hypofunction in GABAergic interneurons results in the modulation of the cortical network oscillation, particularly in the gamma range (30–80 Hz. These gamma-band oscillation (GBO abnormalities were found to lead to the cognitive deficits observed in the disorder. Postmortem mRNA studies have shown that SST decreased more significantly than any other biomarker in schizophrenic subjects. The functional role of Somatostatin (SST in the aetiology of SZ can be studied through its receptors. Genetic knockout studies in animal models in Huntington's disease (HD have shown that a specific SST receptor, SSTR2, is increased along with the increased NMDAR activity, with opposing patterns observed in SZ. A direct correlation between SSTR and NMDAR is hence inferred in this review with the hope of finding a potential new therapeutic target for the treatment of SZ and related neurological conditions.

  9. Clinical value of somatostatin receptor imaging in patients with suspected head and neck paragangliomas

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Matthias; Dietlein, Markus; Weber, Kerstin; Moka, Detlef; Schicha, Harald [Klinik und Poliklinik fuer Nuklearmedizin, Universitaet zu Koeln, Joseph-Stelzmann-Strasse 9, 50924 Koeln (Germany); Fischer, Eva; Michel, Olaf; Stennert, Eberhard [Klinik und Poliklinik fuer Hals-, Nasen- und Ohrenheilkunde, Universitaet zu Koeln, Koeln (Germany)

    2002-12-01

    Paragangliomas or glomus tumours of the head and neck region are rare somatostatin receptor-expressing neuroendocrine tumours. Precise preoperative diagnosis is of special importance in order to adequately weigh the potential benefit of the operation against the inherent risks of the procedure. In this study, the clinical value of somatostatin receptor imaging was assessed in 19 patients who underwent somatostatin receptor scintigraphy because of known or suspected paraganglioma of the head and neck region. The results were compared with the results of computed tomography and/or magnetic resonance imaging, histology and clinical follow-up. [{sup 111}In-DTPA-D-Phe{sup 1}]-octreotide scintigraphy was performed 4-6 and 24 h after i.v. injection of 140-220 MBq {sup 111}In-octreotide. Whole-body and planar images as well as single-photon emission tomography images were acquired and lesions were graded according to qualitative tracer uptake. Somatostatin receptor imaging was positive in nine patients, identifying paragangliomas for the first time in three patients and recurrent disease in six patients. In one patient, a second, previously unknown paraganglioma site was identified. Negative results were obtained in ten patients. These patients included one suffering from chronic hyperplastic otitis externa, one with granuloma tissue and an organised haematoma, one with an acoustic neuroma, one with an asymmetric internal carotid artery, two with ectasia of the bulbus venae jugularis and one with a jugular vein thrombosis. In two patients with a strong family history of paraganglioma, individual involvement could be excluded. In only one patient did somatostatin receptor imaging and magnetic resonance imaging yield false negative results in respect of recurrent paraganglioma tissue. It is concluded that somatostatin receptor scintigraphy provides important information in patients with suspected paragangliomas of the head and neck region and has a strong impact on further

  10. Experimental peptide receptor radionuclide therapy in radioiodine negative somatostatin receptor positive thyroid cancer

    International Nuclear Information System (INIS)

    Nilica, B.; Kroiss, A.; Putzer, D.; Uprimmy, C.; Warwitz, B.; Kendler, D.; Waitz, D.; Virgolini, I.

    2015-01-01

    Full text of publication follows. Purpose: This retrospective analysis evaluated the time to progression (TTP), progression free survival (PFS) and overall survival (OS) in patients with radioiodine negative thyroid cancer who had undergone peptide receptor radionuclide therapy (PRRT) with 177 Lu-DOTA-TATE, 177 Lu-DOTA-LAN, 90 Y-DOTA-TOC or 90 Y-DOTA-LAN after tumor progression. Methods: Data derived from twenty patients with either differentiated (n=15), anaplastic (n=1) or medullary (n=4) somatostatin receptor positive thyroid cancer who had received treatment with PRRT after tumor progression. TTP, PFS and OS were defined according to the clinical trial endpoints suggested by the FDA (Food and Drug Administration). Progressive disease was defined by sonography, FDG-PET, Ga-DOTA-TOC-PET, or CT (RECIST Criteria). Results: In 17 patients the median overall survival time after the first PRRT was 17.3 (range: 0.1 - 109.7) months. Three patients still alive are actually showing stable disease. The median of PFS in 20 Patients (6 with more than one PRRT-cycle or PRRT-substance) has been 10.9 (range: 0.1 - 44.0) months. The median TTP was 15.6 (range 4.4 to 29.2) months. Conclusion: PRRT appears to be useful in patients with somatostatin receptor positive but radioiodine negative thyroid cancer as a complementary palliative cytotoxic therapy. (authors)

  11. The Inhibitory Effect of Somatostatin Receptor Activation on Bee Venom-Evoked Nociceptive Behavior and pCREB Expression in Rats

    Directory of Open Access Journals (Sweden)

    Li Li

    2014-01-01

    Full Text Available The present study examined nociceptive behaviors and the expression of phosphorylated cAMP response element-binding protein (pCREB in the dorsal horn of the lumbar spinal cord and the dorsal root ganglion (DRG evoked by bee venom (BV. The effect of intraplantar preapplication of the somatostatin analog octreotide on nociceptive behaviors and pCREB expression was also examined. Subcutaneous injection of BV into the rat unilateral hindpaw pad induced significant spontaneous nociceptive behaviors, primary mechanical allodynia, primary thermal hyperalgesia, and mirror-thermal hyperalgesia, as well as an increase in pCREB expression in the lumbar spinal dorsal horn and DRG. Octreotide pretreatment significantly attenuated the BV-induced lifting/licking response and mechanical allodynia. Local injection of octreotide also significantly reduced pCREB expression in the lumbar spinal dorsal horn and DRG. Furthermore, pretreatment with cyclosomatostatin, a somatostatin receptor antagonist, reversed the octreotide-induced inhibition of the lifting/licking response, mechanical allodynia, and the expression of pCREB. These results suggest that BV can induce nociceptive responses and somatostatin receptors are involved in mediating the antinociception, which provides new evidence for peripheral analgesic action of somatostatin in an inflammatory pain state.

  12. NMDA receptor antagonists inhibit catalepsy induced by either dopamine D1 or D2 receptor antagonists.

    Science.gov (United States)

    Moore, N A; Blackman, A; Awere, S; Leander, J D

    1993-06-11

    In the present study, we investigated the ability of NMDA receptor antagonists to inhibit catalepsy induced by haloperidol, or SCH23390 and clebopride, selective dopamine D1 and D2 receptor antagonists respectively. Catalepsy was measured by recording the time the animal remained with its forepaws placed over a rod 6 cm above the bench. Pretreatment with either the non-competitive NMDA receptor antagonist, MK-801 (0.25-0.5 mg/kg i.p.) or the competitive antagonist, LY274614 (10-20 mg/kg i.p.) reduced the cataleptic response produced by haloperidol (10 mg/kg), SCH23390 (2.5-10 mg/kp i.p.) or clebopride (5-20 mg/kg i.p.). This demonstrates that NMDA receptor antagonists will reduce both dopamine D1 and D2 receptor antagonist-induced catalepsy. Muscle relaxant doses of chlordiazepoxide (10 mg/kg i.p.) failed to reduce the catalepsy induced by haloperidol, suggesting that the anticataleptic effect of the NMDA receptor antagonists was not due to a non-specific action. These results support the hypothesis that NMDA receptor antagonists may have beneficial effects in disorders involving reduced dopaminergic function, such as Parkinson's disease.

  13. Carboxyl-terminal multi-site phosphorylation regulates internalization and desensitization of the human sst2 somatostatin receptor.

    Science.gov (United States)

    Lehmann, Andreas; Kliewer, Andrea; Schütz, Dagmar; Nagel, Falko; Stumm, Ralf; Schulz, Stefan

    2014-04-25

    The somatostatin receptor 2 (sst2) is the pharmacological target of somatostatin analogs that are widely used in the diagnosis and treatment of human neuroendocrine tumors. We have recently shown that the stable somatostatin analogs octreotide and pasireotide (SOM230) stimulate distinct patterns of sst2 receptor phosphorylation and internalization. Like somatostatin, octreotide promotes the phosphorylation of at least six carboxyl-terminal serine and threonine residues namely S341, S343, T353, T354, T356 and T359, which in turn leads to a robust receptor endocytosis. Unlike somatostatin, pasireotide stimulates a selective phosphorylation of S341 and S343 of the human sst2 receptor followed by a partial receptor internalization. Here, we show that exchange of S341 and S343 by alanine is sufficient to block pasireotide-driven internalization, whereas mutation of T353, T354, T356 and T359 to alanine is required to strongly inhibited both octreotide- and somatostatin-induced internalization. Yet, combined mutation of T353, T354, T356 and T359 is not sufficient to prevent somatostatin-driven β-arrestin mobilization and receptor desensitization. Replacement of all fourteen carboxyl-terminal serine and threonine residues by alanine completely abrogates sst2 receptor internalization and β-arrestin mobilization in HEK293 cells. Together, our findings demonstrate for the first time that agonist-selective sst2 receptor internalization is regulated by multi-site phosphorylation of its carboxyl-terminal tail. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. 99m Tc- la bed somatostatin analogs for imaging somatostatin-receptor-positive tumors

    International Nuclear Information System (INIS)

    Gandomkar, M.; Najafi, R.; Shafiei, A.; Sadat Ebrahimi, E.; Babaie, M.H.; Rabani, M.

    2002-01-01

    Over the least few years, 111 In-DTPA- Octreotide has found widespread clinical applicability, especially in oncology. However limitation, especially concerning availability, imaging properties, and costs, remain and have stimulated research on radiolabeling with many alternative radionuclides. The purpose of this investigation was to labeling somatostatin analogs with 99 m Tc and evaluate their suitability as an agents for in vivo use. Octreotide and Tyr-3-Octreotide were labeled by 99 mTc with direct and indirect methods. Sodium ascorbate and sodium dithionite were used for reduction of cystine bridge and HYNIC was used as bifunctional agents and different co ligands used for labeling by 99 mTc. Yield of labeling, purity, stability, internalisation, binding affinity and biodistribution of peptide conjugates were studied. Direct labeling of octreotide was simple, rapid, efficient and yield was good (%60). K d for binding affinity as high (10 -9 ) but stability was low. Labeling for HYNIC-Tyr-Octreotide had a high yield (>%90), good stability, internalisation and biodistribution. with more experimental work and some improve this peptide-based radiopharmaceuticals can be employed in all nuclear medicine centers as a useful agent for imaging of tumors

  15. Small molecule antagonists of integrin receptors.

    Science.gov (United States)

    Perdih, A; Dolenc, M Sollner

    2010-01-01

    The complex and widespread family of integrin receptors is involved in numerous physiological processes, such as tissue remodeling, angiogenesis, development of the immune response and homeostasis. In addition, their key role has been elucidated in important pathological disorders such as cancer, cardiovascular diseases, osteoporosis, autoimmune and inflammatory diseases and in the pathogenesis of infectious diseases, making them highly important targets for modern drug design campaigns. In this review we seek to present a concise overview of the small molecule antagonists of this diverse and highly complex receptor family. Integrin antagonists are classified according to the targeted integrin receptor and are discussed in four sections. First we present the fibrinogen alpha(IIb)beta3 and the vitronectin alpha (V)beta(3) receptor antagonists. The remaining selective integrin antagonists are examined in the third section. The final section is dedicated to molecules with dual or multiple integrin activity. In addition, the use of antibodies and peptidomimetic approaches to modulate the integrin receptors are discussed, as well providing the reader with an overall appreciation of the field.

  16. Pharmacological analysis of calcium antagonist receptors

    International Nuclear Information System (INIS)

    Reynolds, I.J.

    1987-01-01

    This work focuses on two aspects of the action of calcium antagonist drugs, namely, the interaction of drugs with receptors for verapamil-like calcium antagonists, and the interactions of drugs with voltage-sensitive calcium fluxes in rat brain synaptosomes. From binding studies I have found that the ligand of choice for labeling the verapamil receptor is (-)[ 3 H]desmethoxy-verapamil. This drug labels potently, reversibly and stereoselectively two receptors in membranes prepared from rat brain and rabbit skeletal muscle tissues. In equilibrium studies dihydropyridine calcium antagonists interact in a non-competitive fashion, while many non-DHPs are apparently competitive. In-depth kinetic studies in skeletal muscle membranes indicate that the two receptors are linked in a negative heterotropic fashion, and that low-affinity binding of (-) [ 3 H]desmethoxy-verapamil may be to the diltiazem receptor. However, these studies were not able to distinguish between the hypothesis that diltiazem binds to spatially separate, allosterically coupled receptors, and the hypothesis that diltiazem binds to a subsite of the verapamil receptor

  17. Receptor binding of somatostatin-14 and somatostatin-28 in rat brain: differential modulation by nucleotides and ions.

    Science.gov (United States)

    Srikant, C B; Dahan, A; Craig, C

    1990-02-04

    The tissue-selective binding of the two principal bioactive forms of somatostatin, somatostatin-14 (SS-14) and somatostatin-28 (SS-28), their ability to modulate cAMP-dependent and -independent regulation of post-receptor events to different degrees and the documentation of specific labelling of SS receptor subtypes with SS-28 but not SS-14 in discrete regions of rat brain suggest the existence of distinct SS-14 and SS-28 binding sites. Receptor binding of SS-14 ligands has been shown to be modulated by nucleotides and ions, but the effect of these agents on SS-28 binding has not been studied. In the present study we investigated the effects of adenine and guanine nucleotides as well as monovalent and divalent cations on rat brain SS receptors quantitated with radioiodinated analogs of SS-14 ([125I-Tyr11]SS14, referred to in this paper as SS-14) and SS-28 ([Leu8, D-Trp22, 125I-Tyr25] SS-28, referred to as LTT* SS-28) in order to determine if distinct receptor sites for SS-14 and SS-28 could be distinguished on the basis of their modulation by nucleotides and ions. GTP as well as ATP exerted a dose-dependent inhibition (over a concentration range of 10(-7)-10(-3) M) of the binding of the two radioligands. The nucleotide inhibition of binding resulted in a decrease the Bmax of the SS receptors, the binding affinity remaining unaltered. GTP (10(-4) M) decreased the Bmax of LTT* SS-28 binding sites to a greater extent than ATP (145 +/- 10 and 228 +/- 16 respectively, compared to control value of 320 +/- 20 pmol mg-1). Under identical conditions GTP was less effective than ATP in reducing the number of T* SS-14 binding sites (Bmax = 227 +/- 8 and 182 +/- 15, respectively, compared to 340 +/- 15 pmol mg-1 in the absence of nucleotides). Monovalent cations inhibited the binding of both radioligands, Li+ and Na+ inhibited the binding of T* SS-14 to a greater extent than K+. The effect of divalent cations on the other hand was varied. At low concentration (2 mM) Mg2+, Ba2

  18. Critical role of somatostatin receptor 2 in the vulnerability of the central noradrenergic system

    DEFF Research Database (Denmark)

    Ádori, Csaba; Glück, Laura; Barde, Swapnali

    2015-01-01

    Alzheimer’s disease and other age-related neurodegenerative disorders are associated with deterioration of the noradrenergic locus coeruleus (LC), a probable trigger for mood and memory dysfunction. LC noradrenergic neurons exhibit particularly high levels of somatostatin binding sites. This is n......Alzheimer’s disease and other age-related neurodegenerative disorders are associated with deterioration of the noradrenergic locus coeruleus (LC), a probable trigger for mood and memory dysfunction. LC noradrenergic neurons exhibit particularly high levels of somatostatin binding sites...... morphometry and mRNA profiling in a cohort of Alzheimer’s and age-matched control brains in combination with genetic models of somatostatin receptor deficiency to establish causality between defunct somatostatin signalling and noradrenergic neurodegeneration. In Alzheimer’s disease, we found significantly....../IV and onwards, i.e., a process preceding advanced Alzheimer’s pathology. The loss of SSTR2 transcripts in the LC neurons appeared selective, since tyrosine hydroxylase, dopamine β-hydroxylase, galanin or galanin receptor 3 mRNAs remained unchanged. We modeled these pathogenic changes in Sstr2 −/− mice and...

  19. Medicinal Chemistry of Competitive Kainate Receptor Antagonists

    Science.gov (United States)

    2010-01-01

    Kainic acid (KA) receptors belong to the group of ionotropic glutamate receptors and are expressed throughout in the central nervous system (CNS). The KA receptors have been shown to be involved in neurophysiological functions such as mossy fiber long-term potentiation (LTP) and synaptic plasticity and are thus potential therapeutic targets in CNS diseases such as schizophrenia, major depression, neuropathic pain and epilepsy. Extensive effort has been made to develop subtype-selective KA receptor antagonists in order to elucidate the physiological function of each of the five subunits known (GluK1−5). However, to date only selective antagonists for the GluK1 subunit have been discovered, which underlines the strong need for continued research in this area. The present review describes the structure−activity relationship and pharmacological profile for 10 chemically distinct classes of KA receptor antagonists comprising, in all, 45 compounds. To the medicinal chemist this information will serve as reference guidance as well as an inspiration for future effort in this field. PMID:22778857

  20. High sensitivity of the in vivo detection of somatostatin receptors by 111Indium (DTPA-Octreotide)-scintigraphy in meningioma patients

    International Nuclear Information System (INIS)

    Hildebrandt, G.; Luyken, C.; Klug, N.; Scheidhauer, K.; Schicha, H.; Dahms, P.; Krisch, B.

    1994-01-01

    The recent availability of isotope-labelled somatostatin analogues has allowed one to detect somatostatin receptors in normal tissue as well as in endocrine or non-endocrine cranial tumours. The purpose of the present study was to establish the value of somatostatin receptor scintigraphy using an 111 indium-labelled somatostatin analogue, octreotide, in the diagnostic work-up of meningioma patients. Twenty-two patients (16 women, 6 men, aged from 19-70 years) with newly diagnosed, residual or recurrent cranial meningiomas were examined. 111 indium-labelled DTPA-octreotide was injected i.v.. Planar and tomographic images were obtained with a gamma camera 4-6, and 24 hours after injection. In all of the meningiomas studies a high density of somatostatin receptor was detected by scintigraphy. No false negative test result was found. Due to this, a 100% predictive value of a negative test was calculated. However, when the tumours were taken in culture differing staining intensity could be seen in the light- and electron microscopic level even on individual cells of a single culture when silver intensified somatostatin-gold was used as ligand. We conclude, that in vivo somatostatin receptor scintigraphy may aid in the pre-operative differential diagnosis of skull base tumours

  1. Diagnostic value of somatostatin receptor scintigraphy in patients with intracranial tumours

    International Nuclear Information System (INIS)

    Luyken, C.; Hildebrandt, G.; Scheidhauer, K.; Kirsch, B.

    1993-01-01

    The aim of the study was to detect the SR binding sites in intracranial tumours and to evaluate the benefit of SRS in pre- and postoperative diagnostics. 86 patients with 94 intracranial tumours (39 meningiomas, 18 pituitary adenomas, 11 gliomas grade 3 or 4, 8 gliomas grade 2, 5 neurinomas, 5 intracranial metastases, 4 tumours of the orbit, 2 neurofibromas, 1 brain abscess and 1 cystic lesion) were examined. 111 In-octreotide was injected i.v. as 10 μg or 20 μg bolus, corresponding to 110 or 220 MBq (3 or 6 mCi). Gamma-camera images and SPECT were obtained 3-6 h and 24 h post injection. The scintigraphic evaluation was performed without knowledge of CT and MRI results. The histological classification corresponded to the WHO grading system. Somatostatin binding sites were detected in vito using somatostatin-gold conjugates. All patients with meningiomas showed a high focal tracer uptake corresponding to SR binding sites in vitro, whereas only in 50% of the pituitary adenomas SRS was positive. Neurinomas did not show any tracer uptake. In patients with gliomas with disturbed blood-brain-barrier positive tracer uptake was detected, while none of the gliomas with intact blood-brain-barrier could be visualized by SRS but showed somatostatin binding sites in vitro. In intracranial metastases a local tracer uptake was detected in vivo. In vitro 3 of 4 cases showed somatostatin binding sites. In 2 cases extracranial tracer uptake showed the primary tumour and metastases of the lymphnodes. Somatostatin receptor scintigraphy can help to detect or to exclude meningiomas especially in the cerebellopontine angle or in the orbit. In intracranial metastases SRS may point to the primary tumour or other metastases. In all other intracranial tumours receptor scintigraphy provides no clinical relevant information. (orig./MG) [de

  2. Role of somatostatin receptor-2 in gentamicin-induced auditory hair cell loss in the Mammalian inner ear.

    Directory of Open Access Journals (Sweden)

    Yves Brand

    Full Text Available Hair cells and spiral ganglion neurons of the mammalian auditory system do not regenerate, and their loss leads to irreversible hearing loss. Aminoglycosides induce auditory hair cell death in vitro, and evidence suggests that phosphatidylinositol-3-kinase/Akt signaling opposes gentamicin toxicity via its downstream target, the protein kinase Akt. We previously demonstrated that somatostatin-a peptide with hormone/neurotransmitter properties-can protect hair cells from gentamicin-induced hair cell death in vitro, and that somatostatin receptors are expressed in the mammalian inner ear. However, it remains unknown how this protective effect is mediated. In the present study, we show a highly significant protective effect of octreotide (a drug that mimics and is more potent than somatostatin on gentamicin-induced hair cell death, and increased Akt phosphorylation in octreotide-treated organ of Corti explants in vitro. Moreover, we demonstrate that somatostatin receptor-1 knockout mice overexpress somatostatin receptor-2 in the organ of Corti, and are less susceptible to gentamicin-induced hair cell loss than wild-type or somatostatin-1/somatostatin-2 double-knockout mice. Finally, we show that octreotide affects auditory hair cells, enhances spiral ganglion neurite number, and decreases spiral ganglion neurite length.

  3. The potential value of somatostatin receptor scintigraphy in medullary thyroid carcinoma

    International Nuclear Information System (INIS)

    Doerr, U.; Bihl, H.; Frank-Raue, K.; Raue, F.; Sautter-Bihl, M.L.; Buhr, H.J.; Guzman, G.; Inst. de Neurocirugia, Investigationes Cerebrales 'Dr Asenjo' Santiago

    1993-01-01

    In a prospective study, ten patients with recurrent medullary thyroid carcinoma (markedly elevated calcitonin levels) were investigated by means of somatostatin receptor scintigraphy (SRS) with 111 In-pentetreotide. Scintigraphically, 30 sites of pathological uptake were found, mostly located in the neck and upper mediastinum. So far, 18 suspected tumour sites underwent histological examination and 14 of them could be verified as metastases of medullary thyroid carcinoma (MTC). The remaining four putative tumour lesions turned out to be false positive scintigraphic findings caused by chronic inflammation and somatostatin receptor positive tumours other than MTC. We conclude that SRS is a promising imaging modality for localization of MTC recurrence and may thus make a contribution to better management of this patient group. (Author)

  4. Ga-68 Somatostatin Receptor PET/CT in von Hippel-Lindau Disease

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Jong-Ryool; Min, Jung-Joon [Chonnam National Univ. Hwasun Hospital, Hwasun (Korea, Republic of); Kulkarui, Harshad; Carreras, Cecilia; Schalch, Georg; Baum, Richard P. [Nuclear Medicine and Center for PET/CT, Zentralk Bad Berka, Bad Verka (Germany)

    2012-06-15

    Von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome with a variety of benign and malignant tumors such as retinal and central nervous system hemangioblastomas, endolymphatic sac tumors, renalcysts and tumors, pancreatic cysts and tumors, pheochromo-cytomas, and epididymal cystadenomas. Cross-sectional mo-dalities (computed tomography and magnetic resonance imaging) as well as ultrasound play a major role in the initial evaluation and follow-up of the various manifestations of VHL disease. Ga-68-labeled somatostatin receptor analogs already have a significant role in the diagnosis, staging, and therapy management of neuroendocrine neoplasms and neural crest tumors. Herein, we report a case presenting a variety of malignancies in VHL and showing the usefulness of Ga-68 somatostatin receptor PET/CT as a one-stop-shop imaging modality in the management of VHL disease.

  5. Ga-68 Somatostatin Receptor PET/CT in von Hippel-Lindau Disease

    International Nuclear Information System (INIS)

    Oh, Jong-Ryool; Min, Jung-Joon; Kulkarui, Harshad; Carreras, Cecilia; Schalch, Georg; Baum, Richard P.

    2012-01-01

    Von Hippel-Lindau (VHL) disease is a dominantly inherited familial cancer syndrome with a variety of benign and malignant tumors such as retinal and central nervous system hemangioblastomas, endolymphatic sac tumors, renalcysts and tumors, pancreatic cysts and tumors, pheochromo-cytomas, and epididymal cystadenomas. Cross-sectional mo-dalities (computed tomography and magnetic resonance imaging) as well as ultrasound play a major role in the initial evaluation and follow-up of the various manifestations of VHL disease. Ga-68-labeled somatostatin receptor analogs already have a significant role in the diagnosis, staging, and therapy management of neuroendocrine neoplasms and neural crest tumors. Herein, we report a case presenting a variety of malignancies in VHL and showing the usefulness of Ga-68 somatostatin receptor PET/CT as a one-stop-shop imaging modality in the management of VHL disease

  6. The potential value of somatostatin receptor scintigraphy in medullary thyroid carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Doerr, U.; Bihl, H. (Katharinenhospital, Stuttgart (Germany). Dept. of Nuclear Medicine); Frank-Raue, K.; Raue, F. (Heidelberg Univ. (Germany). Dept. of Internal Medicine); Sautter-Bihl, M.L.; Buhr, H.J. (Staedt. Klinikum, Karlsruhe (Germany). Dept. of Radiooncology and Nuclear Medicine); Guzman, G. (Katherinenhospital, Stuttgart (Germany). Dept. of Nuclear Medicine Inst. de Neurocirugia, Investigationes Cerebrales ' Dr Asenjo' Santiago (Chile). Dept. de Medicina Nuclear)

    1993-06-01

    In a prospective study, ten patients with recurrent medullary thyroid carcinoma (markedly elevated calcitonin levels) were investigated by means of somatostatin receptor scintigraphy (SRS) with [sup 111]In-pentetreotide. Scintigraphically, 30 sites of pathological uptake were found, mostly located in the neck and upper mediastinum. So far, 18 suspected tumour sites underwent histological examination and 14 of them could be verified as metastases of medullary thyroid carcinoma (MTC). The remaining four putative tumour lesions turned out to be false positive scintigraphic findings caused by chronic inflammation and somatostatin receptor positive tumours other than MTC. We conclude that SRS is a promising imaging modality for localization of MTC recurrence and may thus make a contribution to better management of this patient group. (Author).

  7. Somatostatin receptor scintigraphy - a case report and review of the literature

    International Nuclear Information System (INIS)

    Yamaga, Lilian Yuri Itaya; Belfer, Aron J.; Segal, Amisa

    1997-01-01

    The authors report a case of carcinoid tumor, diagnosed in a 75-year-old male patient, confirmed by laparotomy and anatomo-pathological study. The patient was examined by somatostatin receptor scintigraphy with In-pentetreotide, and correlation was performed with I-MIBG and CT scan. A review of current literature about this new tracer for detection of carcinoid tumor is presented. (author)

  8. Molecular imaging of neuroendocrine tumors using 68Ga-labeled peptides (Somatostatin receptor PET/CT)

    International Nuclear Information System (INIS)

    Baum, R.P.; Prasad, V.; Hoersch, D.

    2009-01-01

    Receptor PET/CT using 68 Ga-labeled somatostatin analogues (DOTA-NOC, DOTA-TOC or DOTA-TATE) enables the highly sensitive molecular imaging of neuroendocrine tumors (NETs) based on the expression of somatostatin receptors and even the detection of receptor subtypes. Our experience after more than 3000 studies shows that receptor PET/CT has a significantly higher tumor detection rate than conventional scintigraphy (even in SPECT/CT technique), and that tumor lesions can be very accurately localized. By calculating standardized uptake values (SUV) - which are reproducible and investigator-independent - patients can be selected for peptide receptor radiotherapy and also the course after therapy can be controlled. Receptor-PET/CT is the most sensitive imaging modality for the detection of unknown primary tumors (CUP syndrome), which is especially true for the detection of neuroendocrine tumors of the pancreas and small bowel; whole-body staging (''one stop shop'') as well as restaging and selection of patients for peptide receptor radiotherapy can be performed using a patient-friendly procedure (examination finished within one hour) exposing the patient to less radiation than whole-body CT scanning. The 68 Ge/ 68 Ga generator has proved very reliable over the years - even in a hospital environment. The effective costs for 68 Ga labeled somatostatin analogues might be less than for scintigraphic agents, provided a certain number of studies per year are performed. The development of new tumor-specific peptides as well as of other DOTA- or NOTA-coupled radiopharmaceuticals opens a new avenue into the future: finally, the 68 Ga generator could play a similar important role for PET/CT as did the 99m Tc-Generator for conventional gamma camera imaging over the last decades. (orig.)

  9. Somatostatin Receptor Scintigraphy (SRS) with 99m-Tc HYNIC-TOC

    International Nuclear Information System (INIS)

    Zarlenga, A.C.; Parma, P.; Arashiro, J.; Castiglia, S.; Obenaus, E.

    2002-01-01

    Background: This compound is a synthetic analogue of somatostatin by conjugating the Hydrazinocotinamide (Hynic) to Tyr 3 -Octreotide (Toc) radiolabeling via quelation with 99m Tc. Purpose: We have analyzed the feasibility in detecting neuroendocrine tumors (NET) by somatostatin receptor with 99m Tc Hynic-Toc. Methods: After comparative studies between 99m Tc Hynic-Toc and 111 In (pentetreotide) with excellent correlation, we have performed 48 scintigrams with 99m Tc Hynic-Toc. 35 patients with suspicions of NET were included (19 women, 16 men. Age range 22-75 y). We have performed planar images at 1,2,24 hs and tomographic images at 150 min after intravenous injection of 740 MBq 99m Tc Hynic-Toc. We compare the results with other diagnosis modalities and /or the histopathological findings after biopsy or surgery. Results: True Positive:17; True Negative:11; False Positive: 4; False Negative:3. Specificity=73.3%; Sensitivity=85%; Accuracy=80%; Not adverse effects were observed. Conclusions: 99m Tc Hynic-Toc is not limited availability of the isotope. It is a suitable radiopharmaceutical for in vivo evaluation to define tumor receptor status, staging, and for identification of patients who may benefit from therapy with somatostatin. The tumor uptake at 24 hs allows a better visualization of abdominal tumor sites. Tc Hynic-Toc is an alternative to 111 In-pentetreotide for imaging somatostatin receptor positive tumors. The study was offered to patients whom the scintigraphy with 111 In-pentetreotide offers a diagnosis alternative with high specificity and accessible cost

  10. Selective central activation of somatostatin receptor 2 increases food intake, grooming behavior and rectal temperature in rats.

    Science.gov (United States)

    Stengel, A; Goebel, M; Wang, L; Rivier, J; Kobelt, P; Monnikes, H; Tache, Y

    2010-08-01

    The consequences of selective activation of brain somatostatin receptor-2 (sst2) were assessed using the sst2 agonist, des-AA(1,4-6,11-13)-[DPhe(2),Aph7(Cbm),DTrp(8)]-Cbm-SST-Thr-NH2. Food intake (FI) was monitored in ad libitum fed rats chronically implanted with an intracerebroventricular (i.c.v.) cannula. The sst(2) agonist injected i.c.v. at 0.1 and 1 microg/rat dose-dependently increased light phase FI from 2 to 6 hours post injection (2.3+/-0.5 and 7.5+/-1.2 respectively vs. vehicle: 0.2+/-0.2 g/300 g bw, P<0.001). Peptide action was reversed by i.c.v. injection of the sst2 antagonist, des-AA(1,4-6,11-13)-[pNO(2)-Phe(2),DCys(3),Tyr(7),DAph(Cbm)8]-SST-2Nal-NH(2) and not reproduced by intraperitoneal injection (30 microg/rat). The sst(2) antagonist alone i.c.v. significantly decreased the cumulative 14-hours dark phase FI by 29.5%. Other behaviors, namely grooming, drinking and locomotor activity were also increased by the sst(2) agonist (1 microg/rat, i.c.v.) as monitored during the 2(nd) hour post injection while gastric emptying of solid food was unaltered. Rectal temperature rose 1 hour after the sst(2) agonist (1 microg/rat, i.c.v.) with a maximal response maintained from 1 to 4 hours post injection. These data show that selective activation of the brain sst(2) receptor induces a feeding response in the light phase not associated with changes in gastric emptying. The food intake reduction following sst(2) receptor blockade suggests a role of this receptor in the orexigenic drive during the dark phase.

  11. Diagnostic value of somatostatin receptor scintigraphy in patients with intracranial tumours. Diagnostische Wertigkeit der Somatostatin-Rezeptor-Szintigraphie bei Patienten mit intrakraniellen Raumforderungen

    Energy Technology Data Exchange (ETDEWEB)

    Luyken, C. (Klinik fuer Neurochirurgie, Koeln Univ. (Germany)); Hildebrandt, G. (Klinik fuer Neurochirurgie, Koeln Univ. (Germany)); Scheidhauer, K. (Klinik fuer Nuklearmedizin, Koeln Univ. (Germany)); Kirsch, B. (Anatomisches Inst., Kiel Univ. (Germany))

    1993-12-01

    The aim of the study was to detect the SR binding sites in intracranial tumours and to evaluate the benefit of SRS in pre- and postoperative diagnostics. 86 patients with 94 intracranial tumours (39 meningiomas, 18 pituitary adenomas, 11 gliomas grade 3 or 4, 8 gliomas grade 2, 5 neurinomas, 5 intracranial metastases, 4 tumours of the orbit, 2 neurofibromas, 1 brain abscess and 1 cystic lesion) were examined. [sup 111]In-octreotide was injected i.v. as 10 [mu]g or 20 [mu]g bolus, corresponding to 110 or 220 MBq (3 or 6 mCi). Gamma-camera images and SPECT were obtained 3-6 h and 24 h post injection. The scintigraphic evaluation was performed without knowledge of CT and MRI results. The histological classification corresponded to the WHO grading system. Somatostatin binding sites were detected in vito using somatostatin-gold conjugates. All patients with meningiomas showed a high focal tracer uptake corresponding to SR binding sites in vitro, whereas only in 50% of the pituitary adenomas SRS was positive. Neurinomas did not show any tracer uptake. In patients with gliomas with disturbed blood-brain-barrier positive tracer uptake was detected, while none of the gliomas with intact blood-brain-barrier could be visualized by SRS but showed somatostatin binding sites in vitro. In intracranial metastases a local tracer uptake was detected in vivo. In vitro 3 of 4 cases showed somatostatin binding sites. In 2 cases extracranial tracer uptake showed the primary tumour and metastases of the lymphnodes. Somatostatin receptor scintigraphy can help to detect or to exclude meningiomas especially in the cerebellopontine angle or in the orbit. In intracranial metastases SRS may point to the primary tumour or other metastases. In all other intracranial tumours receptor scintigraphy provides no clinical relevant information. (orig./MG)

  12. 99mTc-EDDA/HYNIC-TOC somatostatin receptor scintigraphy in daily clinical practice.

    Science.gov (United States)

    Chrapko, Beata Ewa; Nocuń, Anna; Gołebiewska, Renata; Stefaniak, Bogusław; Korobowicz, Elzbieta; Czekajska-Chehab, Elzbieta; Sawicki, Marek; Polkowski, Wojciech Piotr

    2010-04-01

    This study aimed to assess the impact of 99mTc-EDDA/HYNIC-TOC (99mTc-TOC) somatostatin receptor scintigraphy (SRS) in clinical practice. One hundred seventeen patients were divided into 6 groups: 1, initial detection and localization of suspected neuroendocrine tumor (NET); 2, tumor staging before therapy; 3, staging of NET of unknown origin, 4, restaging after surgery of primary tumor; 5, diagnosis of solitary pulmonary nodules (SPNs), and 6, follow-up after "cold" somatostatin analogues treatment. In group 1, clinical suspicions were not confirmed in any of the patients; in group 2, most of the primary lesions showed overexpression of somatostatin receptors (SSRT); in group 3, the primary tumor was not identified in any of the patients; in group 4, recurrences were depicted in 7 out of 47 patients; in group 5, only 1 malignant SPN was detected, and in group 6, regression of primary mass and metastases were seen on follow-up SRS in 1 patient. 99mTc-TOC SRS is useful in staging of SSRT-overexpressing tumors of known and unknown primary origin, as well as in restaging after primary tumor surgery. This method is less effective in detecting suspected NET and assessing SPNs. Further investigation is necessary to evaluate the usefulness of SRS in monitoring patients after biological treatment.

  13. Honey Bee Allatostatins Target Galanin/Somatostatin-Like Receptors and Modulate Learning: A Conserved Function?

    Directory of Open Access Journals (Sweden)

    Elodie Urlacher

    Full Text Available Sequencing of the honeybee genome revealed many neuropeptides and putative neuropeptide receptors, yet functional characterization of these peptidic systems is scarce. In this study, we focus on allatostatins, which were first identified as inhibitors of juvenile hormone synthesis, but whose role in the adult honey bee (Apis mellifera brain remains to be determined. We characterize the bee allatostatin system, represented by two families: allatostatin A (Apime-ASTA and its receptor (Apime-ASTA-R; and C-type allatostatins (Apime-ASTC and Apime-ASTCC and their common receptor (Apime-ASTC-R. Apime-ASTA-R and Apime-ASTC-R are the receptors in bees most closely related to vertebrate galanin and somatostatin receptors, respectively. We examine the functional properties of the two honeybee receptors and show that they are transcriptionally expressed in the adult brain, including in brain centers known to be important for learning and memory processes. Thus we investigated the effects of exogenously applied allatostatins on appetitive olfactory learning in the bee. Our results show that allatostatins modulate learning in this insect, and provide important insights into the evolution of somatostatin/allatostatin signaling.

  14. Somatostatin receptor 1 and 5 double knockout mice mimic neurochemical changes of Huntington's disease transgenic mice.

    Directory of Open Access Journals (Sweden)

    Padmesh S Rajput

    Full Text Available Selective degeneration of medium spiny neurons and preservation of medium sized aspiny interneurons in striatum has been implicated in excitotoxicity and pathophysiology of Huntington's disease (HD. However, the molecular mechanism for the selective sparing of medium sized aspiny neurons and vulnerability of projection neurons is still elusive. The pathological characteristic of HD is an extensive reduction of the striatal mass, affecting caudate putamen. Somatostatin (SST positive neurons are selectively spared in HD and Quinolinic acid/N-methyl-D-aspartic acid induced excitotoxicity, mimic the model of HD. SST plays neuroprotective role in excitotoxicity and the biological effects of SST are mediated by five somatostatin receptor subtypes (SSTR1-5.To delineate subtype selective biological responses we have here investigated changes in SSTR1 and 5 double knockout mice brain and compared with HD transgenic mouse model (R6/2. Our study revealed significant loss of dopamine and cAMP regulated phosphoprotein of 32 kDa (DARPP-32 and comparable changes in SST, N-methyl-D-aspartic acid receptors subtypes, calbindin and brain nitric oxide synthase expression as well as in key signaling proteins including calpain, phospho-extracellular-signal-regulated kinases1/2, synapsin-IIa, protein kinase C-α and calcineurin in SSTR1/5(-/- and R6/2 mice. Conversely, the expression of somatostatin receptor subtypes, enkephalin and phosphatidylinositol 3-kinases were strain specific. SSTR1/5 appears to be important in regulating NMDARs, DARPP-32 and signaling molecules in similar fashion as seen in HD transgenic mice.This is the first comprehensive description of disease related changes upon ablation of G- protein coupled receptor gene. Our results indicate that SST and SSTRs might play an important role in regulation of neurodegeneration and targeting this pathway can provide a novel insight in understanding the pathophysiology of Huntington's disease.

  15. Somatostatin receptor gene therapy combined with targeted therapy with radiolabeled octreotide: a new treatment for liver metastases.

    NARCIS (Netherlands)

    A. Mearadji (Amir); W.A.P. Breeman (Wouter); L.J. Hofland (Leo); R.L. Marquet (Richard); J. Jeekel (Hans); E.P. Krenning (Eric); C.H.J. van Eijck (Casper); P.M. van Koetsveld (Peter)

    2002-01-01

    textabstractOBJECTIVE: To evaluate the effect of peptide receptor radionuclide therapy (PRRT) on somatostatin receptor (SSR)-transfected colon carcinoma cells in a rat liver metastases model.SUMMARY BACKGROUND DATA: Previously the authors have shown highly effective therapy with

  16. Antiallergic effects of H1-receptor antagonists.

    Science.gov (United States)

    Baroody, F M; Naclerio, R M

    2000-01-01

    The primary mechanism of antihistamine action in the treatment of allergic diseases is believed to be competitive antagonism of histamine binding to cellular receptors (specifically, the H1-receptors), which are present on nerve endings, smooth muscles, and glandular cells. This notion is supported by the fact that structurally unrelated drugs antagonize the H1-receptor and provide clinical benefit. However, H1-receptor antagonism may not be their sole mechanism of action in treating allergic rhinitis. On the basis of in vitro and animal experiments, drugs classified as H1-receptor antagonists have long been recognized to have additional pharmacological properties. Most first-generation H1-antihistamines have anticholinergic, sedative, local anaesthetic, and anti-5-HT effects, which might favourably affect the symptoms of the allergic response but also contribute to side-effects. These additional properties are not uniformly distributed among drugs classified as H1-receptor antagonists. Azatadine, for example, inhibits in vitro IgE-mediated histamine and leukotriene (LT) release from mast cells and basophils. In human challenge models, terfenadine, azatadine, and loratadine reduce IgE-mediated histamine release. Cetirizine reduces eosinophilic infiltration at the site of antigen challenge in the skin, but not the nose. In a nasal antigen challenge model, cetirizine pretreatment did not affect the levels of histamine and prostaglandin D2 recovered in postchallenge lavages, whereas the levels of albumin, N-tosyl-L-arginine methyl ester (TAME) esterase activity, and LTs were reduced. Terfenadine, cetirizine, and loratadine blocked allergen-induced hyperresponsiveness to methacholine. In view of the complexity of the pathophysiology of allergy, a number of H1 antagonists with additional properties are currently under development for allergic diseases. Mizolastine, a new H1-receptor antagonist, has been shown to have additional actions that should help reduce the

  17. DOTA-derivatives of octreotide dicarba-analogues with high affinity for somatostatin sst2,5 receptors

    Science.gov (United States)

    Pratesi, Alessandro; Ginanneschi, Mauro; Lumini, Marco; Papini, Anna M.; Novellino, Ettore; Brancaccio, Diego; Carotenuto, Alfonso

    2017-02-01

    In vivo somatostatin receptor scintigraphy is a valuable method for the visualization of human endocrine tumours and their metastases. In fact, peptide ligands of somatostatin receptors (sst’s) conjugated with chelating agents are in clinical use. We have recently developed octreotide dicarba-analogues, which show interesting binding profiles at sst’s. In this context, it was mandatory to explore the possibility that our analogues could maintain their activity also upon conjugation with DOTA. In this paper, we report and discuss the synthesis, binding affinity and conformational preferences of three DOTA-conjugated dicarba-analogues of octreotide. Interestingly, two conjugated analogues exhibited nanomolar affinities on sst2 and sst5 somatostatin receptor subtypes.

  18. Correlation of Somatostatin Receptor-2 Expression with Gallium-68-DOTA-TATE Uptake in Neuroblastoma Xenograft Models

    OpenAIRE

    Zhang, Libo; Vines, Douglass C.; Scollard, Deborah A.; McKee, Trevor; Komal, Teesha; Ganguly, Milan; Do, Trevor; Wu, Bing; Alexander, Natasha; Vali, Reza; Shammas, Amer; Besanger, Travis; Baruchel, Sylvain

    2017-01-01

    Peptide-receptor imaging and therapy with radiolabeled somatostatin analogs such as 68Ga-DOTA-TATE and 177Lu-DOTA-TATE have become an effective treatment option for SSTR-positive neuroendocrine tumors. The purpose of this study was to evaluate the correlation of somatostatin receptor-2 (SSTR2) expression with 68Ga-DOTA-TATE uptake and 177Lu-DOTA-TATE therapy in neuroblastoma (NB) xenograft models. We demonstrated variable SSTR2 expression profiles in eight NB cell lines. From micro-PET imagin...

  19. Somatostatin receptor scintigraphy in sarcoidosis: relation to selected clinical and laboratory markers.

    Science.gov (United States)

    Piotrowski, Wojciech J; Bieńkiewicz, Małgorzata; Frieske, Izabella; Marczak, Jerzy; Antczak, Adam; Górski, Paweł; Kuśmierek, Jacek; Płachcińska, Anna

    2012-01-01

    Discriminating between active and inactive sarcoidosis may be problematic in everyday clinical practice. There are numerous biochemical markers used in the diagnosis and monitoring of sarcoidosis. Somatostatin receptor (SR) scintigraphy with the use of 99mTc-octreotide may be used to estimate disease activity. The aim of the paper was to assess the value of traditional biomarkers (serum angiotensin-converting enzyme [SACE], C-reactive protein, markers of calcium metabolism, bronchoalveolar lavage fluid [BALF] lymphocytes) and a novel biomarker, 8-isoprostane (8-IP) in exhaled breath condensate (EBC), in the assessment of sarcoidosis activity in relation to somatostatin receptor scintigraphy. The study included 32 patients with sarcoidosis. Scintigraphy was performed using somatostatin analogue, 99mTc-HYNIC-TOC; planar and SPECT/CT images were recorded. The study group was divided into a subgroup with positive radiotracer uptake (n = 20) and without a visible uptake (n = 12). 8-IP levels were measured in EBC by an immunoenzymatic assay. RESULTS We observed a significantly higher EBC 8-IP levels in the subgroup with positive uptake compared with those with negative uptake (19.1 ± 19.8 vs. 5.4 ± 3.5 pg/ml, P = 0.02). The levels of SACE and the percentage of BALF lymphocytes were also nonsignificantly elevated. In the group of patients with positive scintigraphy results, a positive correlation was observed between the uptake ratio and SACE (r = 0.44, P = 0.041). The results indicate low value of biochemical markers in the assessment of disease activity. SR scintigraphy may have practical usefulness in the monitoring of sarcoidosis.

  20. Somatostatin receptor 2 knockout/lacZ knockin mice show impaired motor coordination and reveal sites of somatostatin action within the striatum.

    Science.gov (United States)

    Allen, Jeremy P; Hathway, Gareth J; Clarke, Neil J; Jowett, Mike I; Topps, Stephanie; Kendrick, Keith M; Humphrey, Patrick P A; Wilkinson, Lawrence S; Emson, Piers C

    2003-05-01

    The peptide somatostatin can modulate the functional output of the basal ganglia. The exact sites and mechanisms of this action, however, are poorly understood, and the physiological context in which somatostatin acts is unknown. Somatostatin acts as a neuromodulator via a family of five 7-transmembrane G protein-coupled receptors, SSTR1-5, one of which, SSTR2, is known to be functional in the striatum. We have investigated the role of SSTR2 in basal ganglia function using mice in which Sstr2 has been inactivated and replaced by the lacZ reporter gene. Analysis of Sstr2lacZ expression in the brain by beta-galactosidase histochemistry demonstrated a widespread pattern of expression. By comparison to previously published in situ hybridization and immunohistochemical data, Sstr2lacZ expression was shown to accurately recapitulate that of Sstr2 and thus provided a highly sensitive model to investigate cell-type-specific expression of Sstr2. In the striatum, Sstr2 expression was identified in medium spiny projection neurons restricted to the matrix compartment and in cholinergic interneurons. Sstr2 expression was not detected in any other nuclei of the basal ganglia except for a sparse number of nondopaminergic neurons in the substantia nigra. Microdialysis in the striatum showed Sstr2-null mice were selectively refractory to somatostatin-induced dopamine and glutamate release. In behavioural tests, Sstr2-null mice showed normal levels of locomotor activity and normal coordination in undemanding tasks. However, in beam-walking, a test of fine motor control, Sstr2-null mice were severely impaired. Together these data implicate an important neuromodulatory role for SSTR2 in the striatum.

  1. Thrombin-receptor antagonist vorapaxar in acute coronary syndromes

    DEFF Research Database (Denmark)

    Tricoci, Pierluigi; Huang, Zhen; Held, Claes

    2012-01-01

    Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation.......Vorapaxar is a new oral protease-activated-receptor 1 (PAR-1) antagonist that inhibits thrombin-induced platelet activation....

  2. Synthesis of a Fluorescently Labeled 68Ga-DOTA-TOC Analog for Somatostatin Receptor Targeting.

    Science.gov (United States)

    Ghosh, Sukhen C; Hernandez Vargas, Servando; Rodriguez, Melissa; Kossatz, Susanne; Voss, Julie; Carmon, Kendra S; Reiner, Thomas; Schonbrunn, Agnes; Azhdarinia, Ali

    2017-07-13

    Fluorescently labeled imaging agents can identify surgical margins in real-time to help achieve complete resections and minimize the likelihood of local recurrence. However, photon attenuation limits fluorescence-based imaging to superficial lesions or lesions that are a few millimeters beneath the tissue surface. Contrast agents that are dual-labeled with a radionuclide and fluorescent dye can overcome this limitation and combine quantitative, whole-body nuclear imaging with intraoperative fluorescence imaging. Using a multimodality chelation (MMC) scaffold, IRDye 800CW was conjugated to the clinically used somatostatin analog, 68 Ga-DOTA-TOC, to produce the dual-labeled analog, 68 Ga-MMC(IRDye 800CW)-TOC, with high yield and specific activity. In vitro pharmacological assays demonstrated retention of receptor-targeting properties for the dual-labeled compound with robust internalization that was somatostatin receptor (SSTR) 2-mediated. Biodistribution studies in mice identified the kidneys as the primary excretion route for 68 Ga-MMC(IRDye 800CW)-TOC, along with clearance via the reticuloendothelial system. Higher uptake was observed in most tissues compared to 68 Ga-DOTA-TOC but decreased as a function of time. The combination of excellent specificity for SSTR2-expressing cells and suitable biodistribution indicate potential application of 68 Ga-MMC(IRDye 800CW)-TOC for intraoperative detection of SSTR2-expressing tumors.

  3. δ-opioid receptor and somatostatin receptor-4 heterodimerization: possible implications in modulation of pain associated signaling.

    Directory of Open Access Journals (Sweden)

    Rishi K Somvanshi

    Full Text Available Pain relief is the principal action of opioids. Somatostatin (SST, a growth hormone inhibitory peptide is also known to alleviate pain even in cases when opioids fail. Recent studies have shown that mice are prone to sustained pain and devoid of analgesic effect in the absence of somatostatin receptor 4 (SSTR4. In the present study, using brain slices, cultured neurons and HEK-293 cells, we showed that SSTR4 and δ-Opioid receptor (δOR exist in a heteromeric complex and function in synergistic manner. SSTR4 and δOR co-expressed in cortical/striatal brain regions and spinal cord. Using cultured neuronal cells, we describe the heterogeneous complex formation of SSTR4 and δOR at neuronal cell body and processes. Cotransfected cells display inhibition of cAMP/PKA and co-activation of SSTR4 and δOR oppose receptor trafficking induced by individual receptor activation. Furthermore, downstream signaling pathways either associated with withdrawal or pain relief are modulated synergistically with a predominant role of SSTR4. Inhibition of cAMP/PKA and activation of ERK1/2 are the possible cellular adaptations to prevent withdrawal induced by chronic morphine use. Our results reveal direct intra-membrane interaction between SSTR4 and δOR and provide insights for the molecular mechanism for the anti-nociceptive property of SST in combination with opioids as a potential therapeutic approach to avoid undesirable withdrawal symptoms.

  4. Multiple Targeting Approaches on Histamine H3 Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Mohammad eKhanfar

    2016-05-01

    Full Text Available With the very recent market approval of pitolisant (Wakix®, the interest in clinical applications of novel multifunctional histamine H3 receptor antagonists has clearly increased. Since histamine H3 receptor antagonists in clinical development have been tested for a variety of different indications, the combination of pharmacological properties in one molecule for improved pharmacological effects and reduced unwanted side-effects is rationally based on the increasing knowledge on the complex neurotransmitter regulations. The polypharmacological approaches on histamine H3 receptor antagonists on different G-protein coupled receptors, transporters, enzymes as well as on NO-signaling mechanism are described, supported with some lead structures.

  5. NK-1 receptor antagonists as anti-cancer drugs

    Indian Academy of Sciences (India)

    The substance P (SP)/neurokinin (NK)-1 receptor system plays an important role in cancer. SP promotes the proliferation of tumour cells, angiogenesis and the migration of tumour cells. We review the involvement of SP, the NK-1 receptor and NK-1 receptor antagonists in cancer. Tumour cells overexpress NK-1 receptors, ...

  6. Synthesis and evaluation of ligand targeting the somatostatin receptor for drug delivery to tumor cell

    Energy Technology Data Exchange (ETDEWEB)

    Lee, So Young; Hong, Young Don; Jung, Sung Hee; Choi, Sun Ju [Radioisotope Research Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-12-15

    Most of targeted therapies block the action of certain enzymes, proteins, or other molecules involved in the growth and spread of cancer cells to produce its cytotoxic effect. Either small molecule drugs or monoclonal antibodies are mostly used in targeted therapies. Unfortunately, targeted therapy has a certain degree of unwanted side effect like other cytotoxicity inducing chemotherapies. To overcome and to reduce unwanted side effects during a cancer therapy, recently radiopeptide therapies has got the worlds' attraction for the tumor targeting modalities due to its beneficial effect on less side effect compared to cytotoxic chemotherapies. Among radiopeptide therapies, {sup 177}Lu-DOTATATE is a major modality as an effective one invented so far in treating neuroendocrine tumor (NET) and it has been in clinical trials at least one decade. Although it does have rather effective therapeutic effect on NET, it has less effective in rather large solid tumor. There are many ways to improve or increase therapeutic effect of radiopeptide are a finding the potent small molecules to target the tumor site selectively, or a labeling with radioisotope of emitting high energy, or an improving its biological half-life by introducing different moieties to increase lipophilicity. Present study was focus to increase a biological halflife of radio somatostatin which will target the somatostatin receptor by altering the bifunctional chelator (BFCA) by introducing lipophilic moiety to the somatostatin, which would make the labeled peptide stay longer in the tumor site and thus it can intensify the therapeutic effect on tumor cell itself and around tissues.

  7. Novel, potent, and radio-iodinatable somatostatin receptor 1 (sst1) selective analogues.

    Science.gov (United States)

    Erchegyi, Judit; Cescato, Renzo; Grace, Christy Rani R; Waser, Beatrice; Piccand, Véronique; Hoyer, Daniel; Riek, Roland; Rivier, Jean E; Reubi, Jean Claude

    2009-05-14

    The proposed sst(1) pharmacophore (J. Med. Chem. 2005, 48, 523-533) derived from the NMR structures of a family of mono- and dicyclic undecamers was used to design octa-, hepta-, and hexamers with high affinity and selectivity for the somatostatin sst(1) receptor. These compounds were tested for their in vitro binding properties to all five somatostatin (SRIF) receptors using receptor autoradiography; those with high SRIF receptor subtype 1 (sst(1)) affinity and selectivity were shown to be agonists when tested functionally in a luciferase reporter gene assay. Des-AA(1,4-6,10,12,13)-[DTyr(2),DAgl(NMe,2naphthoyl)(8),IAmp(9)]-SRIF-Thr-NH(2) (25) was radio-iodinated ((125)I-25) and specifically labeled sst(1)-expressing cells and tissues. 3D NMR structures were calculated for des-AA(1,4-6,10,12,13)-[DPhe(2),DTrp(8),IAmp(9)]-SRIF-Thr-NH(2) (16), des-AA(1,2,4-6,10,12,13)-[DAgl(NMe,2naphthoyl)(8),IAmp(9)]-SRIF-Thr-NH(2) (23), and des-AA(1,2,4-6,10,12,13)-[DAgl(NMe,2naphthoyl)(8),IAmp(9),Tyr(11)]-SRIF-NH(2) (27) in DMSO. Though the analogues have the sst(1) pharmacophore residues at the previously determined distances from each other, the positioning of the aromatic residues in 16, 23, and 27 is different from that described earlier, suggesting an induced fit mechanism for sst(1) binding of these novel, less constrained sst(1)-selective family members.

  8. Somatostatin receptor scintigraphy in advanced renal cell carcinoma. Results of a phase II-trial of somatostatine analogue therapy in patients with advanced RCC

    International Nuclear Information System (INIS)

    Freudenberg, L.S.; Goerges, R.; Stergar, H.; Bockisch, A.; Gauler, T.; Bauer, S.; Antoch, G.; Schuette, J.

    2008-01-01

    Aims: objective of this prospective study was to evaluate the role of somatostatin receptor scintigraphy (SRS) in advanced renal cell carcinoma (RCC) with respect to potential therapy with somatostatin analogue (SST-A) and to assess the response rate under therapy with SST-A. Patients, methods: 16 patients with documented progression of histologically confirmed advanced RCC were included. Planar whole-body SRS was performed 4, 24 and 48h post i.v. injection of 175-200 MBq 111 In-pentetreoide. 5 and 25 h p.i. SPECT of thorax and abdomen were performed. Documentation of somatostatin receptor expression via SRS in > 50% of known tumour lesions was the criteria for treatment start with SST-A (Sandostatin LAR registered -Depot 30mg i.m. every four weeks). Results: in 9/16 of the patients SRS showed at least one metastasis with moderate (n = 5) or intense (n = 4) tracer uptake. Lesion-based SRS evaluation showed only 12.1% (20/165) of all metastases. Most false-negative lesions were located in the lungs. In too patients, the majority of the known metastases was SRS positive and these patients received SST-A therapy. The first radiographic evaluation after a two-month interval showed progressive disease in both patients. Conclusions: we conclude that SRS is of limited value in staging of advanced RCC. In our patients SST-A did not result in a growth control of RCC. Consequently, the use of SST-A in advanced RCC seems to be no relevant therapeutic option. (orig.)

  9. Molecular imaging with 68Ga-SSTR PET/CT and correlation to immunohistochemistry of somatostatin receptors in neuroendocrine tumours

    International Nuclear Information System (INIS)

    Kaemmerer, Daniel; Haugvik, Sven-Petter; Hommann, Merten; Peter, Luisa; Lupp, Amelie; Schulz, Stefan; Saenger, Joerg; Prasad, Vikas; Kulkarni, Harshad; Baum, Richard Paul

    2011-01-01

    Somatostatin receptors (SSTR) are known for an overexpression in gastroenteropancreatic neuroendocrine tumours (GEP-NET). The aim of the present study was to find out if the receptor density predicted by the semi-quantitative parameters generated from the static positron emission tomography (PET/CT) correlated with the in vitro immunohistochemistry using a novel rabbit monoclonal anti-SSTR2A antibody (clone UMB-1) for specific SSTR2A immunohistochemistry and polyclonal antibodies for SSTR1 and 3-5. Overall 14 surgical specimens generated from 34 histologically documented GEP-NET patients were correlated with the preoperative 68 Ga-DOTA-NOC PET/CT. Quantitative assessment of the receptor density was done using the immunoreactive score (IRS) of Remmele and Stegner; the additional 4-point IRS classification for immunohistochemistry and standardized uptake values (SUV max and SUV mean ) were used for PET/CT. The IRS for SSTR2A and SSTR5 correlated highly significant with the SUV max on the PET/CT (p mean (p max on the 68 Ga-DOTA-NOC PET/CT scans is concordant with the affinity profile of 68 Ga-DOTA-NOC to the SSTR subtypes and demonstrates the excellent qualification of somatostatin analogues in the diagnostics of NET. This study correlating somatostatin receptor imaging using 68 Ga-DOTA-NOC PET/CT with immunohistochemically analysed SSTR also underlines the approval of therapy using somatostatin analogues, follow-up imaging as well as radionuclide therapy. (orig.)

  10. Studies on mRNA expression of the somatostatin receptor family in lung cancer

    International Nuclear Information System (INIS)

    Wang Jing; Deng Jinglan; Wu Shengxi; Qiao Hongqing

    2000-01-01

    Objective: To investigate the characteristics of expression and distribution of 5 subtypes of somatostatin receptors (SSTR1∼5) in lung cancer. Methods: With [α- 35 S]dATP labelled oligonucleotides of the 5 SSTR subtypes as probes, using in situ hybridization, patterns of mRNA expression were detected in lung cancer tissue sections of 21 cases which fell in varied pathologic types. Additionally, Leica Q-500 image analyzing device was employed to semi-quantitatively analyze density of the expression. Results: Patterns of SSTR1∼5 expression in lung cancer were as follows: SSTR2 expression was dominant in small cell lung cancer (SCLC) while in non-small cell lung cancer (NSCLC) such as adenous and squamous, SSTR1 expression was stronger than that of the other 4 subtypes, In density of SSTR1∼5 expression in lung cancer, NSCLC was higher than SCLC (P<0.01). Conclusions: even though patterns and density of expression of SSTR subtypes in the lung cancer showed heterogeneity in different histopathologic types, as in SCLC and in NSCLC. Therefore, it has positive prospects for somatostatin analog-oriented agents to be used in treatment of both types of the lung cancers

  11. Expression of the somatostatin receptor family mRNAs in lung cancer

    International Nuclear Information System (INIS)

    Wang Jing; Wang Liangang; Deng Jinglan; Wu Shengxi

    2000-01-01

    To investigate the characteristics of expression and distribution of 5 subtypes of somatostatin receptors (SSTR1-5) in lung cancer, in situ hybridization was used to examine the expression patterns of SSTR mRNAs in 21 cases of different pathologic types of lung cancer tissues with [α- 35 S]dATP labelled oligonucleotides of the 5 SSTR subtypes as probes. Additionally, Leica Q-500 image analysis processing system was employed for the semi-quantitatively analysis of the hybridization signals. Patterns of SSTR1-5 expression in lung cancer tissues were found as follows. SSTR2 was prominent in small cell lung cancer (SCLC), whereas in non-small cell lung cancer (NSCLC) including the adenous cancer (Ad) and the squamous cancer (Sq), the expression of SSTR1 mRNA was stronger than that of the other 4 types. the expression density of SSTR1-5 in the NSCLC was higher that the SCLC (p < 0.01). The expression patterns and densities of the SSTR subtypes showed heterogeneity in different pathologic types of lung cancer. The expressions of the SSTR mRNAs in both SCLC and NSCLC indicated the positive prospects for somatostatin analog (SSA)-oriented agents in the treatment of both types of the lung cancer

  12. Analysis of transmission of novel polymorphisms in the somatostatin receptor 5 (SSTR5) gene in patients with autism

    DEFF Research Database (Denmark)

    Lauritsen, Marlene B; Nyegaard, Mette; Betancur, Catalina

    2003-01-01

    growth hormone response has been reported in some individuals with autism. Moreover, the somatostatinergic system interacts with the dopaminergic system, which has been hypothesized to be involved in the etiology of autism; in particular, somatostatin secretion is regulated by dopamine, and the dopamine......Infantile autism is a pervasive developmental disorder with a strong genetic component. The mode of inheritance appears to be complex and no specific susceptibility genes have yet been identified. Chromosome 16p13.3 may contain a susceptibility gene based on findings from genome scans and reports...... of chromosome abnormalities in individuals with autism. The somatostatin receptor 5 (SSTR5) gene is located on chromosome 16p13.3 and is thus a positional candidate gene for autism. SSTR5 may also be a functional candidate gene for autism because somatostatin inhibits growth hormone secretion, and increased...

  13. Interaction between Antagonist of Cannabinoid Receptor and Antagonist of Adrenergic Receptor on Anxiety in Male Rat

    Directory of Open Access Journals (Sweden)

    Alireza Komaki

    2014-07-01

    Full Text Available Introduction: Anxiety is among the most common and treatable mental disorders. Adrenergic and cannabinoid systems have an important role in the neurobiology of anxiety. The elevated plus-maze (EPM has broadly been used to investigate anxiolytic and anxiogenic compounds. The present study investigated the effects of intraperitoneal (IP injection of cannabinoid CB1 receptor antagonist (AM251 in the presence of alpha-1 adrenergic antagonist (Prazosin on rat behavior in the EPM. Methods: In this study, the data were obtained from male Wistar rat, which weighing 200- 250 g. Animal behavior in EPM were videotaped and saved in computer for 10 min after IP injection of saline, AM251 (0.3 mg/kg, Prazosin (0.3 mg/kg and AM251 + Prazosin, subsequently scored for conventional indices of anxiety. During the test period, the number of open and closed arms entries, the percentage of entries into the open arms of the EPM, and the spent time in open and closed arms were recorded. Diazepam was considered as a positive control drug with anxiolytic effect (0.3, 0.6, 1.2 mg/kg. Results: Diazepam increased the number of open arm entries and the percentage of spent time on the open arms. IP injection of AM251 before EPM trial decreased open arms exploration and open arm entry. Whereas, Prazosin increased open arms exploration and open arm entry. This study showed that both substances in simultaneous injection have conflicting effects on the responses of each of these two compounds in a single injection. Discussion: Injection of CB1 receptor antagonist may have an anxiogenic profile in rat, whereas adrenergic antagonist has an anxiolytic effect. Further investigations are essential for better understanding of anxiolytic and anxiogenic properties and neurobiological mechanisms of action and probable interactions of the two systems.

  14. Interaction between Antagonist of Cannabinoid Receptor and Antagonist of Adrenergic Receptor on Anxiety in Male Rat.

    Science.gov (United States)

    Komaki, Alireza; Abdollahzadeh, Fatemeh; Sarihi, Abdolrahman; Shahidi, Siamak; Salehi, Iraj

    2014-01-01

    Anxiety is among the most common and treatable mental disorders. Adrenergic and cannabinoid systems have an important role in the neurobiology of anxiety. The elevated plus-maze (EPM) has broadly been used to investigate anxiolytic and anxiogenic compounds. The present study investigated the effects of intraperitoneal (IP) injection of cannabinoid CB1 receptor antagonist (AM251) in the presence of alpha-1 adrenergic antagonist (Prazosin) on rat behavior in the EPM. In this study, the data were obtained from male Wistar rat, which weighing 200- 250 g. Animal behavior in EPM were videotaped and saved in computer for 10 min after IP injection of saline, AM251 (0.3 mg/kg), Prazosin (0.3 mg/kg) and AM251 + Prazosin, subsequently scored for conventional indices of anxiety. During the test period, the number of open and closed arms entries, the percentage of entries into the open arms of the EPM, and the spent time in open and closed arms were recorded. Diazepam was considered as a positive control drug with anxiolytic effect (0.3, 0.6, 1.2 mg/kg). Diazepam increased the number of open arm entries and the percentage of spent time on the open arms. IP injection of AM251 before EPM trial decreased open arms exploration and open arm entry. Whereas, Prazosin increased open arms exploration and open arm entry. This study showed that both substances in simultaneous injection have conflicting effects on the responses of each of these two compounds in a single injection. Injection of CB1 receptor antagonist may have an anxiogenic profile in rat, whereas adrenergic antagonist has an anxiolytic effect. Further investigations are essential for better understanding of anxiolytic and anxiogenic properties and neurobiological mechanisms of action and probable interactions of the two systems.

  15. Detecting somatostatin receptor in breast tumor tissue and its clinical significance

    International Nuclear Information System (INIS)

    Zhang Yongjian; Yu Xian; Lin Wei; Ding Xuan; Huang Shizhang; Lu Guangming

    2002-01-01

    The authors observe the difference of somatostatin receptor (SSR) between benign and malignant breast tumor and the relation between SSR and estrogen receptor (ER) or progesterone receptor (PR) in breast tumor tissue, and to predict the clinical value of detecting breast tumor by SSR receptor imaging. These tissues excised from operation in breast tumor were divided into 4 groups: breast malignant tumor group (BMTG) and its control group (C1G), breast benign tumor group (BBTG) and its control group (C2G). SSR was detected by radioligand binding assay (RBA) and ER, PR by LsAB method in these groups. Results is: (1) The SSR express quantity is 108.6 +- 67.3 fmol/mg pr, 37.2 +- 9.6 fmol/mg pr, 43.4 +- 12.6 fmol/mg pr 33.9 +- 10.2 fmol/mg pr respectively in BMTG, C1G, BBTG, C2G. The SSR of BMTG is the most among these groups, the difference is obvious, P 0.05); (2) The correlation coefficient of SSR and ER is 0.859, SSR and PR is 0.750. Most breast tumor tissues express high density SSR, the authors suppose that malignant tumor can been distinguished from benign tumor preliminarily by SSR receptor imaging. There is a good correlation between SSR and ER, PR, detecting SSR may predict the quality of tumor and the prognosis of the patient

  16. Treatment of pituitary gigantism with the growth hormone receptor antagonist pegvisomant.

    Science.gov (United States)

    Goldenberg, Naila; Racine, Michael S; Thomas, Pamela; Degnan, Bernard; Chandler, William; Barkan, Ariel

    2008-08-01

    Treatment of pituitary gigantism is complex and the results are usually unsatisfactory. The objective of the study was to describe the results of therapy of three children with pituitary gigantism by a GH receptor antagonist, pegvisomant. This was a descriptive case series of up to 3.5 yr duration. The study was conducted at a university hospital. Patients included three children (one female, two males) with pituitary gigantism whose GH hypersecretion was incompletely controlled by surgery, somatostatin analog, and dopamine agonist. The intervention was administration of pegvisomant. Plasma IGF-I and growth velocity were measured. In all three children, pegvisomant rapidly decreased plasma IGF-I concentrations. Growth velocity declined to subnormal or normal values. Statural growth fell into lower growth percentiles and acromegalic features resolved. Pituitary tumor size did not change in two children but increased in one boy despite concomitant therapy with a somatostatin analog. Pegvisomant may be an effective modality for the therapy of pituitary gigantism in children. Titration of the dose is necessary for optimal efficacy, and regular surveillance of tumor size is mandatory.

  17. Pathophysiology of GPCR Homo- and Heterodimerization: Special Emphasis on Somatostatin Receptors

    Directory of Open Access Journals (Sweden)

    Rishi K. Somvanshi

    2012-04-01

    Full Text Available G-protein coupled receptors (GPCRs are cell surface proteins responsible for translating >80% of extracellular reception to intracellular signals. The extracellular information in the form of neurotransmitters, peptides, ions, odorants etc is converted to intracellular signals via a wide variety of effector molecules activating distinct downstream signaling pathways. All GPCRs share common structural features including an extracellular N-terminal, seven-transmembrane domains (TMs linked by extracellular/intracellular loops and the C-terminal tail. Recent studies have shown that most GPCRs function as dimers (homo- and/or heterodimers or even higher order of oligomers. Protein-protein interaction among GPCRs and other receptor proteins play a critical role in the modulation of receptor pharmacology and functions. Although ~50% of the current drugs available in the market target GPCRs, still many GPCRs remain unexplored as potential therapeutic targets, opening immense possibility to discover the role of GPCRs in pathophysiological conditions. This review explores the existing information and future possibilities of GPCRs as tools in clinical pharmacology and is specifically focused for the role of somatostatin receptors (SSTRs in pathophysiology of diseases and as the potential candidate for drug discovery.

  18. A SELECTIVE ANTAGONIST OF MINERALOCORTICOID RECEPTOR EPLERENONE IN CARDIOLOGY PRACTICE

    Directory of Open Access Journals (Sweden)

    B. B. Gegenava

    2015-01-01

    Full Text Available The role of aldosterone in pathophysiological processes is considered. The effects of the selective antagonist of mineralocorticoid receptor eplerenone are analyzed. The advantages of eplerenone compared with spironolactone are discussed.

  19. 5-HT7 Receptor Antagonists with an Unprecedented Selectivity Profile.

    Science.gov (United States)

    Ates, Ali; Burssens, Pierre; Lorthioir, Olivier; Lo Brutto, Patrick; Dehon, Gwenael; Keyaerts, Jean; Coloretti, Francis; Lallemand, Bénédicte; Verbois, Valérie; Gillard, Michel; Vermeiren, Céline

    2018-04-23

    Selective leads: In this study, we generated a new series of serotonin 5-HT 7 receptor antagonists. Their synthesis, structure-activity relationships, and selectivity profiles are reported. This series includes 5-HT 7 antagonists with unprecedented high selectivity for the 5-HT 7 receptor, setting the stage for lead optimization of drugs acting on a range of neurological targets. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Pertussis toxin modifies the characteristics of both the inhibitory GTP binding proteins and the somatostatin receptor in anterior pituitary tumor cells

    International Nuclear Information System (INIS)

    Mahy, N.; Woolkalis, M.; Thermos, K.; Carlson, K.; Manning, D.; Reisine, T.

    1988-01-01

    The effects of pertussis toxin treatment on the characteristics of somatostatin receptors in the anterior pituitary tumor cell line AtT-20 were examined. Pertussis toxin selectively catalyzed the ADP ribosylation of the alpha subunits of the inhibitory GTP binding proteins in AtT-20 cells. Toxin treatment abolished somatostatin inhibition of forskolin-stimulated adenylyl cyclase activity and somatostatin stimulation of GTPase activity. To examine the effects of pertussis toxin treatment on the characteristics of the somatostatin receptor, the receptor was labeled by the somatostatin analog [125I]CGP 23996. [125I]CGP 23996 binding to AtT-20 cell membranes was saturable and within a limited concentration range was to a single high affinity site. Pertussis toxin treatment reduced the apparent density of the high affinity [125I]CGP 23996 binding sites in AtT-20 cell membranes. Inhibition of [125I]CGP 23996 binding by a wide concentration range of CGP 23996 revealed the presence of two binding sites. GTP predominantly reduced the level of high affinity sites in control membranes. Pertussis toxin treatment also diminished the amount of high affinity sites. GTP did not affect [125I]CGP 23996 binding in the pertussis toxin-treated membranes. The high affinity somatostatin receptors were covalently labeled with [125I] CGP 23996 and the photoactivated crosslinking agent n-hydroxysuccinimidyl-4-azidobenzoate. No high affinity somatostatin receptors, covalently bound to [125I]CGP 23996, were detected in the pertussis toxin-treated membranes. These results are most consistent with pertussis toxin uncoupling the inhibitory G proteins from the somatostatin receptor thereby converting the receptor from a mixed population of high and low affinity sites to only low affinity receptors

  1. NMDA receptor antagonists for the treatment of neuropathic pain

    NARCIS (Netherlands)

    Collins, S.; Sigtermans, M.J.; Dahan, A.; Zuurmond, W.W.A.; Perez, R.S.G.M.

    2010-01-01

    Objective. The N-methyl-D-Aspartate (NMDA) receptor has been proposed as a primary target for the treatment of neuropathic pain. The aim of the present study was to perform a meta-analysis evaluating the effects of (individual) NMDA receptor antagonists on neuropathic pain, and the response

  2. Management of hyperkalaemia consequent to mineralocorticoid-receptor antagonist therapy

    NARCIS (Netherlands)

    Roscioni, Sara S.; de Zeeuw, Dick; Bakker, Stephan J. L.; Lambers Heerspink, Hiddo J.

    2012-01-01

    Mineralocorticoid-receptor antagonists (MRAs) reduce blood pressure and albuminuria in patients treated with angiotensin-converting-enzyme inhibitors or angiotensin-II-receptor blockers. The use of MRAs, however, is limited by the occurrence of hyperkalaemia, which frequently occurs in patients

  3. Benzodiazepine receptor antagonists for acute and chronic hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Kjaergard, L L; Gluud, C

    2001-01-01

    The pathogenesis of hepatic encephalopathy is unknown. It has been suggested that liver failure leads to the accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition which may progress to coma. Several trials have assessed benzodiazepine receptor...... antagonists for hepatic encephalopathy, but the results are conflicting....

  4. Immunohistochemical Detection and Localization of Somatostatin Receptor Subtypes in Prostate Tissue from Patients with Bladder Outlet Obstruction

    Directory of Open Access Journals (Sweden)

    Rodolfo Montironi

    2008-01-01

    Full Text Available Background and Aim of the Study: Scant information on the cellular distribution of the five somatostatin receptor (SSTR subtypes in the normal prostate and in neoplasms of the prostate has been reported in very few studies in which techniques, such as in situ hybridization histochemistry, autoradiography, and more recently immunohistochemistry, have been applied. The aim of the study was to examine immunohistochemically the distribution and localization of these 5 subtypes in the various tissue components in normal prostate.

  5. Suvorexant: The first orexin receptor antagonist to treat insomnia

    OpenAIRE

    Dubey, Ashok K.; Handu, Shailendra S.; Mediratta, Pramod K.

    2015-01-01

    Primary insomnia is mainly treated with drugs acting on benzodiazepine receptors and a few other classes of drugs used for different co-morbidities. A novel approach to treat insomnia has been introduced recently, with the approval of suvorexant, the first in a new class of orexin receptor antagonists. Orexin receptors in the brain have been found to play an important role in the regulation of various aspects of arousal and motivation. The drugs commonly used for insomnia therapy to date, hav...

  6. A prototypical Sigma-1 receptor antagonist protects against brain ischemia

    OpenAIRE

    Schetz, John A.; Perez, Evelyn; Liu, Ran; Chen, Shiuhwei; Lee, Ivan; Simpkins, James W.

    2007-01-01

    Previous studies indicate that the Sigma-1 ligand 4-phenyl-1-(4-phenylbutyl) piperidine (PPBP) protects the brain from ischemia. Less clear is whether protection is mediated by agonism or antagonism of the Sigma-1 receptor, and whether drugs already in use for other indications and that interact with the Sigma-1 receptor might also prevent oxidative damage due to conditions such as cerebral ischemic stroke. The antipsychotic drug haloperidol is an antagonist of Sigma-1 receptors and in this s...

  7. Evaluation of somatostatin and nucleolin receptors for therapeutic delivery in non-small cell lung cancer stem cells applying the somatostatin-analog DOTATATE and the nucleolin-targeting aptamer AS1411.

    Directory of Open Access Journals (Sweden)

    Sif Holmboe

    Full Text Available Cancer stem cells represent the putative tumor-driving subpopulation thought to account for drug resistance, relapse, and metastatic spread of epithelial and other cancer types. Accordingly, cell surface markers for therapeutic delivery to cancer stem cells are subject of intense research. Somatostatin receptor 2 and nucleolin are known to be overexpressed by various cancer types, which have elicited comprehensive efforts to explore their therapeutic utilization. Here, we evaluated somatostatin receptor 2 targeting and nucleolin targeting for therapeutic delivery to cancer stem cells from lung cancer. Nucleolin is expressed highly but not selectively, while somatostatin receptor 2 is expressed selectively but not highly by cancer cells. The non-small cell lung cancer cell lines A549 and H1299, displayed average levels of both surface molecules as judged based on analysis of a larger cell line panel. H1299 compared to A549 cells showed significantly elevated sphere-forming capacity, indicating higher cancer stem cell content, thus qualifying as suitable test system. Nucleolin-targeting 57Co-DOTA-AS1411 aptamer showed efficient internalization by cancer cells and, remarkably, at even higher efficiency by cancer stem cells. In contrast, somatostatin receptor 2 expression levels were not sufficiently high in H1299 cells to confer efficient uptake by either non-cancer stem cells or cancer stem cells. The data provides indication that the nucleolin-targeting AS1411 aptamer might be used for therapeutic delivery to non-small cell lung cancer stem cells.

  8. Serotonin 2A receptor antagonists for treatment of schizophrenia

    DEFF Research Database (Denmark)

    Ebdrup, Bjørn Hylsebeck; Rasmussen, Hans; Arnt, Jørn

    2011-01-01

    Introduction: All approved antipsychotic drugs share an affinity for the dopamine 2 (D2) receptor; however, these drugs only partially ameliorate the symptoms of schizophrenia. It is, therefore, of paramount importance to identify new treatment strategies for schizophrenia. Areas covered......: Preclinical, clinical and post-mortem studies of the serotonin 5-HT2A system in schizophrenia are reviewed. The implications of a combined D2 and 5-HT2A receptor blockade, which is obtained by several current antipsychotic drugs, are discussed, and the rationale for the development of more selective 5-HT2A...... receptor antagonists is evaluated. Moreover, the investigational pipeline of major pharmaceutical companies is examined and an Internet search conducted to identify other pharmaceutical companies investigating 5-HT2A receptor antagonists for the treatment of schizophrenia. Expert opinion: 5-HT2A receptor...

  9. Morphological Imaging in the Localization of Neuroendocrine Gastroenteropancreatic Tumors Found by Somatostatin Receptor Scintigraphy

    International Nuclear Information System (INIS)

    Saga, T.; Doi, R.; Endo, K.; Shimatsu, A.; Koizumi, K.; Ichikawa, T.; Yamamoto, K.; Noguchi, S.; Ishibashi, M.; Machinami, R.; Nakamura, K.; Sakahara, H.

    2005-01-01

    Purpose: To evaluate the necessity of morphological images (MI) in reading somatostatin receptor scintigraphy (SRS) in patients with suspected neuroendocrine gastroenteropancreatic (GEP) tumors. Material and Methods: A Japanese multicenter clinical trial of SRS was conducted in 40 patients with suspected GEP tumors. Three experienced radiologists interpreted the images in three separate sessions in a blinded manner (1: SRS images alone, 2: MI alone, 3: SRS and MI analyzed simultaneously), and the reading results of each session were compared. In addition, the diagnostic abilities of SRS, MI and SRS alone and simultaneous SRS and MI readings were compared for patients where final diagnosis was obtained. Results: SRS detected more suspected lesions (positive or inconclusive uptake) than morphological images did (51 vs 27 lesions), but included many physiological uptakes detected as positive or inconclusive uptakes. Combined reading of SRS and morphological images helped to correctly recognize these physiological uptakes, and also helped in determining the anatomical localization of the abnormal uptakes. Combined reading of SRS and morphological images gave the highest diagnostic impact. Conclusion: The sensitivity of SRS with regard to GEP is high. However the specificity is very low. Morphologic imaging is necessary for the exclusion of physiological uptake and correct anatomic location of an abnormal tracer uptake. The combined reading of SRS and morphologic imaging studies gives the highest diagnostic impact

  10. Somatostatin receptor scintigraphy to predict the clinical evolution and therapeutic response of thyroid-associated ophthalmopathy

    International Nuclear Information System (INIS)

    Nocaudie, M.; Bailliez, A.; Itti, E.; Marchandise, X.

    1999-01-01

    Management of thyroid-associated ophthalmopathy remains a topic of controversy. Immunosuppressive treatments have to be applied at peak disease activity and before criteria of severity develop. Expression of somatostatin receptors on activated lymphocytes allows scintigraphic imaging with indium-111 pentetreotide. We conducted a prospective study with 17 patients who presented severe ophthalmopathy (11 Graves' disease, four Hashimoto's thyroiditis, two isolated in appearance: Means' syndrome). Each patient underwent hormonal (free T 3 and TSH) and immunological (TBII) assessment, an orbital computed tomography scan or magnetic resonance imaging, a visual functional examination and 111 In-pentetreotide orbital scintigraphy before undergoing treatment by steroids and/or radiotherapy, independently of scintigraphic results. At 4 and 24 h after the intravenous injection of 111 MBq of 111 In-pentetreotide, planar imaging centred on the head and neck (anterior and both lateral views) was carried out. Retrobulbar uptake was assessed by visual semi-quantitative analysis (score given by two independent trained observers) and by quantitative analyses (regions of interest, orbit/brain uptake indices). Patients were ophthalmologically followed up for 6 months and then classified as improved or not. Visual semi-quantitative analysis of 4-h/24-h planar images was correlated with the ophthalmological evolution (χ 2 test, P 111 In-pentetreotide scintigraphy requires further developments, including quantitative single-photon emission tomographic acquisition, if its role as a guide to therapeutic strategy in thyroid-associated ophthalmopathy is to be confirmed. (orig.)

  11. Ectopic ACTH secretion due to a bronchopulmonary carcinoid localized by somatostatin receptor scintigraphy.

    Science.gov (United States)

    Iser, G; Pfohl, M; Dörr, U; Weiss, E M; Seif, F J

    1994-11-01

    We present the case of a 65-year-old woman with an adrenocorticotropic hormone (ACTH) secreting bronchopulmonary carcinoid. This patient showed the typical long history of Cushing's syndrome, including hypokaliemia, impaired glucose tolerance, high levels of ACTH and beta-endorphin, and coproduction of other peptides. At the onset of clinical symptoms in 1979 an adrenal adenoma was suspected, and left-sided adrenalectomy was performed. The symptoms soon recurred, and the diagnosis of ACTH-dependent Cushing's syndrome was made. As no ACTH-secreting tumor was found, the right adrenal was resected, and the patient was followed up regularly. Fourteen years later chest roentgenography and computed tomography revealed a para-aortic pulmonary lesion, which was suspicious for a bronchopulmonary carcinoid. ACTH and beta-endorphin were excessively, pancreatic polypeptide slightly elevated at that time. The final diagnosis was made using somatostatin receptor scintigraphy which confirmed the hormonal activity of the suspicious lesion; no additional focus was found. This method turned out to be not only a useful additional localization technique but also a promising tool for characterization and staging of a suspected ACTH-producing carcinoid. The tumor was resected curatively, and the diagnosis was confirmed histologically.

  12. Pattern of somatostatin receptors expression in normal and bladder cancer tissue samples.

    Science.gov (United States)

    Karavitakis, Markos; Msaouel, Pavlos; Michalopoulos, Vassilis; Koutsilieris, Michael

    2014-06-01

    Known risks factors for bladder cancer progression and recurrence are limited regarding their prognostic ability. Therefore identification of molecular determinants of disease progression could provide with more specific prognostic information and could be translated into new approaches for biomarker development. In the present study we evaluated, the expression patterns of somatostatin receptors 1-5 (SSTRs) in normal and tumor bladder tissues. The expression of SSTR1-5 was characterized in 45 normal and bladder cancer tissue samples using reverse transcriptase-polymerase chain reaction (RT-PCR). SSTR1 was expressed in 24 samples, SSTR2 in 15, SSTR3 in 23, SSTR4 in 16 and SSTR5 in all but one sample. Bladder cancer tissue samples expressed lower levels of SSTR3. Co-expression of SSTRs was associated with superficial disease. Our results demonstrate, for the first time, that there is expression of SSTR in normal and bladder cancer urothelium. Further studies are required to evaluate the prognostic and therapeutic significance of these findings. Copyright© 2014 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  13. Somatostatin receptor scintigraphy and magnetic resonance imaging in recurrent medullary thyroid carcinoma: A comparative study

    International Nuclear Information System (INIS)

    Doerr, U.; Wuerstlin, S.; Frank-Raue, K.; Raue, F.; Hehrmann, R.; Iser, G.; Scholz, M.; Guhl, L.; Buhr, H.J.; Bihl, H.

    1993-01-01

    In a prospective study, 18 patients with recurrent medullary thyroid carcinoma (MTC) underwent magnetic resonance imaging (MRI) of the neck and mediastinum and somatostatin receptor scintigraphy (SRS) with 111 In-labeled pentetreotide. In nine patients with macroscopic MTC, 17 corresponding lesions were found on MRI and SRS; in addition, 13 suspicious lesions were seen on SRS only. Histological confirmation was available for 19 metastatic lesions, showing MRI to be true positive in 13 metastases, SRS in 18. In minimal residual disease (n=10), MRI and SRS were compared with the histological findings in three patients and with selective venous catheterization (SVC) in seven patients. Corresponding findings on MRI and SVC were seen in one of seven, whereas SRS and SVC showed concordant localization of tumor recurrence in five of seven. Histological examination demonstrated MTC tissue in one of three cases; MRI and SRS were false positive in one of three cases, while in the others the interpretation remained uncertain. In conclusion, SRS is a promising imaging modality for localization of MTC recurrence. MRI provides better spatial resolution and thus facilitates the planning of surgery for macroscopic metastases. In minimal residual disease, SRS turned out to be superior in detecting occult MTC recurrence, confirming SVC findings. (orig.)

  14. Somatostatin receptor scintigraphy and intraoperative gamma probe detection in the localisation and treatment of pancreatic insulinoma

    International Nuclear Information System (INIS)

    Loh, Nelson K.; Macdonald, William B.; Dunne, Marina L.; Rao, Sudhakar

    2009-01-01

    Full text: Aims: We report a case of insulinoma that was successfully enucleated under radio-guidance after an initial unsuccessful laparotomy. This case highlights the utility of Somatostatin Receptor Scintigraphy (SRS) and gamma probe in the localisation and treatment of neuroendocrine tumours. Methods: The patient presented with recurrent hypoglycaemia. An abdominal CT scan identified a lesion in the uncinate process of the pancreas, however, laparotomy with use of intraoperative ultrasound failed to localise the lesion. SRS with SPECTICT was then requested by the surgical team with a view to radio-guided surgery. Results: SRS demonstrated an octreotide-avid tumour in the posterior uncinate process of the pancreas, and confirmed suitability for radio-guided surgery. At re-exploration, the surgeon was again unable to palpate the lesion or localise it with intraoperative ultrasound, however, the lesion was successfully detected and removed with the use of a gamma probe. A postoperative SRS confirmed complete excision and histopathology was diagnostic of insulinoma. Conclusion: This case highlights the utility of SRS in the intraoperative localisation and surgical excision of neuroendocrine tumours. The lesion was unable to be localised clinically or with intraoperative ultrasound but was successfully detected with scintigraphic techniques. The surgical team acknowledge that the use of a gamma probe enabled enucleation of the insulinoma, which obviated the need for an invasive Whipple's procedure.

  15. Somatostatin receptor expression in Merkel cell carcinoma as target for molecular imaging

    International Nuclear Information System (INIS)

    Buder, Kristina; Becker, Jürgen C; Lapa, Constantin; Kreissl, Michael C; Schirbel, Andreas; Herrmann, Ken; Schnack, Alexander; Bröcker, Eva-Bettina; Goebeler, Matthias; Buck, Andreas K

    2014-01-01

    Merkel cell carcinoma (MCC) is a rare cutaneous neoplasm with increasing incidence, aggressive behavior and poor prognosis. Somatostatin receptors (SSTR) are expressed in MCC and represent a potential target for both imaging and treatment. To non-invasively assess SSTR expression in MCC using PET and the radiotracers [ 68 Ga]DOTA-D-Phe 1 -Tyr 3 -octreotide (DOTATOC) or -octreotate (DOTATATE) as surrogate for tumor burden. In 24 patients with histologically proven MCC SSTR-PET was performed and compared to results of computed tomography (CT). SSTR-PET detected primary and metastatic MCC lesions. On a patient-based analysis, sensitivity of SSTR-PET was 73% for nodal metastases, 100% for bone, and 67% for soft-tissue metastases, respectively. Notably, brain metastases were initially detected by SSTR-PET in 2 patients, whereas liver and lung metastases were diagnosed exclusively by CT. SSTR-PET showed concordance to CT results in 20 out of 24 patients. Four patients (17%) were up-staged due to SSTR-PET and patient management was changed in 3 patients (13%). SSTR-PET showed high sensitivity for imaging bone, soft tissue and brain metastases, and particularly in combination with CT had a significant impact on clinical stage and patient management

  16. Endothelin receptor antagonists influence cardiovascular morphology in uremic rats.

    Science.gov (United States)

    Nabokov, A V; Amann, K; Wessels, S; Münter, K; Wagner, J; Ritz, E

    1999-02-01

    In is generally held that renal failure results in blood pressure (BP)-independent structural changes of the myocardium and the vasculature. The contribution, if any, of endothelin (ET) to these changes has been unknown. We morphometrically studied random samples of the left ventricle myocardium and small intramyocardial arteries in subtotally (5/6) nephrectomized (SNx) male Sprague-Dawley rats treated with either the selective ETA receptor antagonist BMS182874 (30 mg/kg/day) or the nonselective ETA/ETB receptor antagonist Ro46-2005 (30 mg/kg/day) in comparison with either sham-operated rats, untreated SNx, or SNx rats treated with the angiotensin-converting enzyme inhibitor trandolapril (0.1 mg/kg/day). Eight weeks later, systolic BP was lower in trandolapril-treated SNx compared with untreated SNx animals. No decrease in BP was seen following either ET receptor antagonist at the dose used. A significantly increased volume density of the myocardial interstitium was found in untreated SNx rats as compared with sham-operated controls. Such interstitial expansion was prevented by trandolapril and either ET receptor antagonist. SNx caused a substantial increase in the wall thickness of small intramyocardial arteries. The increase was prevented by trandolapril or BMS182874 treatment. The arteriolar wall:lumen ratio was significantly lower in all treated groups when compared with untreated SNx. In contrast, only trandolapril, but not the ET receptor antagonists, attenuated thickening of the aortic media in SNx animals. The ETA-selective and ETA/ETB-nonselective receptor antagonists appear to prevent development of myocardial fibrosis and structural changes of small intramyocardial arteries in experimental chronic renal failure. This effect is independent of systemic BP.

  17. Somatostatin and opioid receptors do not regulate proliferation or apoptosis of the human multiple myeloma U266 cells

    Directory of Open Access Journals (Sweden)

    Allouche Stéphane

    2009-06-01

    Full Text Available Abstract Background opioid and somatostatin receptors (SSTRs that can assemble as heterodimer were individually reported to modulate malignant cell proliferation and to favour apoptosis. Materials and methods: SSTRs and opioid receptors expression were examined by RT-PCR, western-blot and binding assays, cell proliferation was studied by XTT assay and propidium iodide (PI staining and apoptosis by annexin V-PI labelling. Results almost all human malignant haematological cell lines studied here expressed the five SSTRs. Further experiments were conducted on the human U266 multiple myeloma cells, which express also μ-opioid receptors (MOP-R. XTT assays and cell cycle studies provide no evidence for a significant effect upon opioid or somatostatin receptors stimulation. Furthermore, neither direct effect nor potentiation of the Fas-receptor pathway was detected on apoptosis after these treatments. Conclusion these data suggest that SSTRs or opioid receptors expression is not a guaranty for an anti-tumoral action in U266 cell line.

  18. Discovery of tertiary sulfonamides as potent liver X receptor antagonists.

    Science.gov (United States)

    Zuercher, William J; Buckholz, Richard G; Campobasso, Nino; Collins, Jon L; Galardi, Cristin M; Gampe, Robert T; Hyatt, Stephen M; Merrihew, Susan L; Moore, John T; Oplinger, Jeffrey A; Reid, Paul R; Spearing, Paul K; Stanley, Thomas B; Stewart, Eugene L; Willson, Timothy M

    2010-04-22

    Tertiary sulfonamides were identified in a HTS as dual liver X receptor (LXR, NR1H2, and NR1H3) ligands, and the binding affinity of the series was increased through iterative analogue synthesis. A ligand-bound cocrystal structure was determined which elucidated key interactions for high binding affinity. Further characterization of the tertiary sulfonamide series led to the identification of high affinity LXR antagonists. GSK2033 (17) is the first potent cell-active LXR antagonist described to date. 17 may be a useful chemical probe to explore the cell biology of this orphan nuclear receptor.

  19. In vivo detection of somatostatin receptors in patients with functionless pituitary adenomas by means of a radioiodinated analog of somatostatin ((123I)SDZ 204-090)

    Energy Technology Data Exchange (ETDEWEB)

    Faglia, G.; Bazzoni, N.; Spada, A.; Arosio, M.; Ambrosi, B.; Spinelli, F.; Sara, R.; Bonino, C.; Lunghi, F. (Institute of Endocrine Sciences, University of Milan, Ospedale Maggiore IRCCS (Italy))

    1991-10-01

    The recent availability of a Tyr3-substituted octreotide (SDZ 204-090) for radioiodination has allowed somatostatin (SRIH) receptor binding to be studied in vivo, and receptor-positive tumors of different origins to be visualized with a gamma-camera. This prompted us to investigate whether this compound could be used for external imaging of functionless pituitary adenomas displaying SRIH receptors. Eight patients with functionless pituitary adenomas, three patients with acromegaly, and three with macroprolactinoma were injected iv with 123I-labeled Tyr3-octreotide and then scanned with a gamma-camera. Positive scans were obtained in the three acromegalics and in two of the eight patients with functionless pituitary tumors. The patients with macroprolactinoma had negative scans. The diagnosis of functionless pituitary adenomas was confirmed by light and electron microscopic examination as well as immunocytochemical studies. In vitro binding of (125I)Tyr11-SRIH to cell membranes was evaluated in four functionless and three GH-secreting adenomas removed from seven of the patients. All of the GH-secreting as well as one of the four functionless adenomas had high affinity SRIH-binding sites, without differences in number or affinity, whereas SRIH-binding sites were not detected in the others. Positive scans were observed only in patients bearing tumors with high affinity SRIH-binding sites. In conclusion, (123I)Tyr3-octreotide appears to be a promising tool for singling out, in vivo, patients with functionless pituitary tumors displaying SRIH receptors who might potentially benefit from octreotide treatment.

  20. Somatostatin receptor 2A expression in choroidal neovascularization secondary to age-related macular degeneration

    NARCIS (Netherlands)

    A.C. Lambooij (Antoinette); R.W.A.M. Kuijpers (Robert); E.G. van Lichtenauer-Kaligis; M. Kliffen (Mike); G.S. Baarsma (Seerp); P.M. van Hagen (Martin); C.M. Mooy (Cornelia)

    2000-01-01

    textabstractPURPOSE: The growth of ocular neovascularization is regulated by a balance between stimulating and inhibiting growth factors. Somatostatin affects angiogenesis by inhibiting the growth hormone-insulin-like growth factor axis and also has a direct

  1. Inverse expression of somatostatin and CXCR4 chemokine receptors in gastroenteropancreatic neuroendocrine neoplasms of different malignancy

    Science.gov (United States)

    Kaemmerer, Daniel; Träger, Tina; Hoffmeister, Maike; Sipos, Bence; Hommann, Merten; Sänger, Järg; Schulz, Stefan; Lupp, Amelie

    2015-01-01

    Introduction Somatostatin receptors (SSTR) are widely distributed in well-differentiated neuroendocrine neoplasms (NEN) and serve as primary targets for diagnostics and treatment. An overexpression of the chemokine receptor CXCR4, in contrast, is considered to be present mainly in highly proliferative and advanced tumors. Comparative data are still lacking, however, for neuroendocrine carcinomas (NEC). Methods SSTR subtype (1, 2A, 3, 5) and CXCR4 expression was evaluated in G1 (n = 31), G2 (n = 47), and low (G3a; Ki-67: 21–49%; n = 21) and highly proliferative (G3b; Ki-67: >50%, n = 22) G3 (total n = 43) gastroenteropancreatic NEN samples by performing immunohistochemistry with monoclonal rabbit anti-human anti-SSTR and anti-CXCR4 antibodies, respectively, and was correlated with clinical data. Results Both CXCR4 and SSTR were widely expressed in all tumors investigated. CXCR4 expression differed significantly between the G1 and G3 specimens and within the G3 group (G3a to G3b), and was positively correlated with Ki-67 expression. SSTR2A, in contrast, exhibited an inverse association with Ki-67. SSTR2A was highly expressed in G1 and G2 tumors, but was significantly less abundant in G3 carcinomas. Additionally, SSTR1 expression was higher in G3a than in G3b tumors. Conclusion We observed an elevation in CXCR4 and a decrease in SSTR2A expression with increasing malignancy. Interestingly, 23% of the G3 specimens had strong SSTR2A expression. Because CXCR4 was strongly expressed in highly proliferative G3 carcinomas, it is an interesting new target and needs to be validated in larger studies. PMID:26259237

  2. Iodine-131 labelled octreotide: not an option for somatostatin receptor therapy

    International Nuclear Information System (INIS)

    Bakker, W.H.; Breeman, W.A.P.; Pluijm, M.E. van der; Jong, M. de; Visser, T.J.; Krenning, E.P.

    1996-01-01

    This study deals with the radioiodination of very small amounts of peptide on a therapeutic scale, the required purification procedures after radioiodination, and the influence of high beta fluxes from 131 I on a peptide during radioiodination and purification. Based on the regularly used therapeutic doses of 131 I in cancer treatment and out previous experience with [ 111 In-DTPA-D-Phe 1 ]-octreotide, it was assumed that a minimal effective therapeutic dose of 3.7 GBq 131 I has to be coupled to a maximum of ∼100 μg peptide, representing only a slight excess of peptide over 131 I. This contrasts with non-peptide radiopharmaceuticals in which high compound to radionuclide ratios are usually used. Labelling at low peptide to radionuclide ratios (low labelling yields) results in the formation of di-iodinated compounds, whereas at high peptide to radionuclide ratios mono-iodinated products of low specific activity are formed. Thus, after radioiodination the desired mono-iodinated peptide has to be separated form unreacted iodide, and from di-iodinated and unreacted peptide, as both compounds compete for the receptors. Possible radiolysis of the peptide during labelling and separation steps were investigated by irradiating 30 μg unlabelled peptide with 370 MBq 131 I in a small volume. The peptide composition of the incubation mixtures was investigated by high-performance liquid chromatography after irradiation for 30 min to 24 h. The results showed that the peptide was degraded with a half-life of less than 1 h. During the preparation of a real therapeutic dose (at much higher β-flux) the peptide will be degraded even faster during the various steps required. In conclusion, intact mono-iodinated 131 I-labelled somatostatin analogues for peptide receptor therapy will be difficult to obtain. (orig./VHE)

  3. Activation of Brain Somatostatin Signaling Suppresses CRF Receptor-Mediated Stress Response

    OpenAIRE

    Andreas Stengel; Yvette F. Taché; Yvette F. Taché

    2017-01-01

    Corticotropin-releasing factor (CRF) is the hallmark brain peptide triggering the response to stress and mediates—in addition to the stimulation of the hypothalamus-pituitary-adrenal (HPA) axis—other hormonal, behavioral, autonomic and visceral components. Earlier reports indicate that somatostatin-28 injected intracerebroventricularly counteracts the acute stress-induced ACTH and catecholamine release. Mounting evidence now supports that activation of brain somatostatin signaling exerts a br...

  4. Value of the radiolabelled GLP-1 receptor antagonist exendin(9-39) for targeting of GLP-1 receptor-expressing pancreatic tissues in mice and humans

    International Nuclear Information System (INIS)

    Waser, Beatrice; Reubi, Jean Claude

    2011-01-01

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. Moreover, it was recently reported that antagonist tracers were superior to agonist tracers for somatostatin and gastrin-releasing peptide receptor targeting of tumours. The present preclinical study determines therefore the value of an established GLP-1 receptor antagonist for the in vitro visualization of GLP-1 receptor-expressing tissues in mice and humans. Receptor autoradiography studies with 125 I-GLP-1(7-36)amide agonist or 125 I-Bolton-Hunter-exendin(9-39) antagonist radioligands were performed in mice pancreas and insulinomas as well as in human insulinomas; competition experiments were performed in the presence of increasing concentration of GLP-1(7-36)amide or exendin(9-39). The antagonist 125 I-Bolton-Hunter-exendin(9-39) labels mouse pancreatic β-cells and mouse insulinomas, but it does not label human pancreatic β-cells and insulinomas. High affinity displacement (IC 50 approximately 2 nM) is observed in mouse β-cells and insulinomas with either the exendin(9-39) antagonist or GLP-1(7-36)amide agonist. For comparison, the agonist 125 I-GLP-1(7-36)amide intensively labels mouse pancreatic β-cells, mouse insulinoma and human insulinomas; high affinity displacement is observed for the GLP-1(7-36)amide in all tissues; however, a 5 and 20 times lower affinity is found for exendin(9-39) in the mouse and human tissues, respectively. This study reports a species-dependent behaviour of the GLP-1 receptor antagonist exendin(9-39) that can optimally target GLP-1 receptors in mice but not in human tissue. Due to its overly low binding affinity, this antagonist is an inadequate targeting agent for human GLP-1 receptor-expressing tissues, as opposed to the GLP-1 receptor agonist, GLP-1(7-36)amide. (orig.)

  5. Value of the radiolabelled GLP-1 receptor antagonist exendin(9-39) for targeting of GLP-1 receptor-expressing pancreatic tissues in mice and humans

    Energy Technology Data Exchange (ETDEWEB)

    Waser, Beatrice; Reubi, Jean Claude [University of Berne, Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, P.O. Box 62, Bern (Switzerland)

    2011-06-15

    Radiolabelled glucagon-like peptide 1 (GLP-1) receptor agonists have recently been shown to successfully image benign insulinomas in patients. Moreover, it was recently reported that antagonist tracers were superior to agonist tracers for somatostatin and gastrin-releasing peptide receptor targeting of tumours. The present preclinical study determines therefore the value of an established GLP-1 receptor antagonist for the in vitro visualization of GLP-1 receptor-expressing tissues in mice and humans. Receptor autoradiography studies with {sup 125}I-GLP-1(7-36)amide agonist or {sup 125}I-Bolton-Hunter-exendin(9-39) antagonist radioligands were performed in mice pancreas and insulinomas as well as in human insulinomas; competition experiments were performed in the presence of increasing concentration of GLP-1(7-36)amide or exendin(9-39). The antagonist {sup 125}I-Bolton-Hunter-exendin(9-39) labels mouse pancreatic {beta}-cells and mouse insulinomas, but it does not label human pancreatic {beta}-cells and insulinomas. High affinity displacement (IC{sub 50} approximately 2 nM) is observed in mouse {beta}-cells and insulinomas with either the exendin(9-39) antagonist or GLP-1(7-36)amide agonist. For comparison, the agonist {sup 125}I-GLP-1(7-36)amide intensively labels mouse pancreatic {beta}-cells, mouse insulinoma and human insulinomas; high affinity displacement is observed for the GLP-1(7-36)amide in all tissues; however, a 5 and 20 times lower affinity is found for exendin(9-39) in the mouse and human tissues, respectively. This study reports a species-dependent behaviour of the GLP-1 receptor antagonist exendin(9-39) that can optimally target GLP-1 receptors in mice but not in human tissue. Due to its overly low binding affinity, this antagonist is an inadequate targeting agent for human GLP-1 receptor-expressing tissues, as opposed to the GLP-1 receptor agonist, GLP-1(7-36)amide. (orig.)

  6. Preparation, formulation and quality control of one step kit 99m Tc - EDDA/HYNIC-Tyr3-Octreotide as a peptide radiopharmaceutical for imaging somatostatin receptor positive tumors

    International Nuclear Information System (INIS)

    Gandomkar, M.; Najafi, R.; Sadat-Ebrahimi, E.; Babaei, M.H.

    2004-01-01

    The high expression of somatostatin receptors in many tumours, have made receptor scintigraphy with 11I n-DTPA-Octreotide a widely used procedure in nuclear medicine. Despite its clinical success, some limitation and drawbacks of radiolabelling with 11I n remain, especially those concerned with the cost, availability and physical decay properties of this radionuclide. 99m Tc - EDDA/HYNIC-Tyr 3 -Octreotide was studied as a new agent with the potential to replace octreoscan in somatostatin receptor scintigraphy. This hydrazino nicotinic acid derivatized somatostatin complex contains ethylenediamine N, N diacetic acid as a co-ligand resulting in a high in vitro and in vivo stability. High labeling yields (>90%) were achieved at high specific activities. Characterization via HPLC, biodistribution and receptor binding of the resulting complex are described. The formulation developed enables rapid and simple labeling of 99m Tc - EDDA/HYNIC-TOC in a manner suitable for clinical setting

  7. Combination decongestion therapy in hospitalized heart failure: loop diuretics, mineralocorticoid receptor antagonists and vasopressin antagonists.

    Science.gov (United States)

    Vaduganathan, Muthiah; Mentz, Robert J; Greene, Stephen J; Senni, Michele; Sato, Naoki; Nodari, Savina; Butler, Javed; Gheorghiade, Mihai

    2015-01-01

    Congestion is the most common reason for admissions and readmissions for heart failure (HF). The vast majority of hospitalized HF patients appear to respond readily to loop diuretics, but available data suggest that a significant proportion are being discharged with persistent evidence of congestion. Although novel therapies targeting congestion should continue to be developed, currently available agents may be utilized more optimally to facilitate complete decongestion. The combination of loop diuretics, natriuretic doses of mineralocorticoid receptor antagonists and vasopressin antagonists represents a regimen of currently available therapies that affects early and persistent decongestion, while limiting the associated risks of electrolyte disturbances, hemodynamic fluctuations, renal dysfunction and mortality.

  8. Enhanced Chronic Pain Management Utilizing Chemokine Receptor Antagonists

    Science.gov (United States)

    2016-08-01

    approximately halfway into the solution. All animals were tested at 60, 15 and 0 min before drug injection. For each animal , the first reading was discarded...approval (December 31, 2015), hiring new personnel, conducting baseline testing for procedures not involving animals , testing equipment, developing...treatment; Analgesia; Nociception; Antinociception; Inflammation; Chemokines; Chemokine receptor antagonists; Opioid analgesics; Animal models of pain

  9. Multiple sclerosis following treatment with a cannabinoid receptor-1 antagonist

    NARCIS (Netherlands)

    van Oosten, B. W.; Killestein, J.; Mathus-Vliegen, E. M. H.; Polman, C. H.

    2004-01-01

    Laboratory research including animal models of human disease suggests that cannabinoids might have therapeutic potential in multiple sclerosis (MS). We have recently seen a 46-year-old woman who developed MS after starting treatment with a cannabinoid receptor antagonist for obesity. The occurrence

  10. Sympatho-inhibitory properties of various AT1 receptor antagonists

    NARCIS (Netherlands)

    Balt, Jippe C.; Mathy, Marie-Jeanne; Pfaffendorf, Martin; van Zwieten, Peter A.

    2002-01-01

    It is well known that angiotensin II (Ang II) can facilitate the effects of sympathetic neurotransmission. In the present study, using various experimental models, we investigated the inhibitory effects of several Ang II subtype 1 receptor (AT1) antagonists on this Ang II-induced facilitation. We

  11. Role of muscarinic receptor antagonists in urgency and nocturia

    NARCIS (Netherlands)

    Michel, Martin C.; de La Rosette, Jean J. M. C. H.

    2005-01-01

    The overactive bladder (OAB) syndrome is defined as urgency, with or without urgency incontinence, usually accompanied by frequency and nocturia. Muscarinic receptor antagonists are the most established form of treatment for OAB, but until recently their effectiveness was only confirmed for symptoms

  12. Efficacy and safety of histamine-2 receptor antagonists

    NARCIS (Netherlands)

    van der Pol, Rachel; Langendam, Miranda; Benninga, Marc; van Wijk, Michiel; Tabbers, Merit

    2014-01-01

    Histamine-2 receptor antagonists (H2RAs) are frequently used in the treatment of gastroesophageal reflux disease (GERD) in children; however, their efficacy and safety is questionable. To systematically review the literature to assess the efficacy and safety of H2RAs in pediatric GERD. PubMed,

  13. Bronchoprotection with a leukotriene receptor antagonist in asthmatic preschool children

    DEFF Research Database (Denmark)

    Bisgaard, H; Nielsen, K G

    2000-01-01

    We hypothesized that a leukotriene receptor antagonist (LTRA) could provide bronchoprotection against the cold, dry air-induced response in asthmatic preschool children. In a randomized, double-blind, placebo-controlled crossover study, we examined the effect of the specific LTRA montelukast at 5...

  14. Multiparametric PET imaging in thyroid malignancy characterizing tumour heterogeneity: somatostatin receptors and glucose metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Traub-Weidinger, Tatjana [Medical University of Vienna, Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Vienna (Austria); Medical University of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Putzer, Daniel; Bale, Reto [Medical University of Innsbruck, Department of Radiology, Innsbruck (Austria); Guggenberg, Elisabeth von; Dobrozemsky, Georg; Nilica, Bernhard; Kendler, Dorota; Virgolini, Irene Johanna [Medical University of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria)

    2015-12-15

    Radiolabelled somatostatin (SST) analogues have proven useful in diagnosing tumours positive for SST receptor (SSTR). As different subtypes of SSTR are expressed on the tumour cell surface, the choice of appropriate therapeutic SST analogue is crucial. We evaluated the SSTR status of thyroid cancer patients who had signs of progressive disease comparing different SSTR ligands for PET imaging to evaluate possible further therapeutic options. PET with {sup 68}Ga-radiolabelled SSTR ligands DOTA lanreotide (DOTA-LAN), DOTA-Tyr{sup 3} octreotide (DOTA-TOC) and {sup 18}F-FDG was performed in 31 patients with thyroid cancer (TC). These 31 patients comprised 18 with radioiodine non-avid differentiated TC (DTC) including 6 papillary TC (PTC), 8 follicular TC (FTC) and 4 oxyphilic TC (oxyTC), 5 with anaplastic TC (ATC), and 8 with medullary TC (MTC). The PET results were compared in a region-based evaluation. All patients underwent a PET study with {sup 68}Ga-DOTA-LAN, 28 patients with {sup 68}Ga-DOTA-TOC and 28 patients with {sup 18}F-FDG. A lack of SSTR expression was found in 13 of the 31 patients (42 %) with negative results with both SSTR tracers in 12 patients. Ambiguous results with both SSTR tracers were observed in one patient. High tracer uptake in SSTR PET images was seen in seven DTC patients (39 %; two PTC, three FTC, two oxyTC), in four ATC patients (80 %) and in six MTC patients (75 %). Lesions showing aerobic glycolysis on {sup 18}F-FDG PET were found in 24 of 28 patients (86 %) with corresponding positive results with {sup 68}Ga-DOTA-LAN in 35 % and with {sup 68}Ga-DOTA-TOC in 29 %. The heterogeneous SSTR profile of TC tumour lesions needs to be evaluated using different SSTR PET tracers to characterize more closely the SSTR subtype affinities in patients with progressive TC in order to further stratify therapy with SSTR therapeutics. (orig.)

  15. Somatostatin receptor scintigraphy to predict the clinical evolution and therapeutic response of thyroid-associated ophthalmopathy

    Energy Technology Data Exchange (ETDEWEB)

    Nocaudie, M.; Bailliez, A.; Itti, E. [Centre Hospitalier Regional et Universitaire, Lille (France). Service Central de Medecine Nucleaire et Imagerie Fonctionnelle; Bauters, C.; Wemeau, J.L. [Clinique d`Endocrinologie, Centre Hospitalier Regional et Universitaire de Lille (France); Marchandise, X.

    1999-05-01

    Management of thyroid-associated ophthalmopathy remains a topic of controversy. Immunosuppressive treatments have to be applied at peak disease activity and before criteria of severity develop. Expression of somatostatin receptors on activated lymphocytes allows scintigraphic imaging with indium-111 pentetreotide. We conducted a prospective study with 17 patients who presented severe ophthalmopathy (11 Graves` disease, four Hashimoto`s thyroiditis, two isolated in appearance: Means` syndrome). Each patient underwent hormonal (free T{sub 3} and TSH) and immunological (TBII) assessment, an orbital computed tomography scan or magnetic resonance imaging, a visual functional examination and {sup 111}In-pentetreotide orbital scintigraphy before undergoing treatment by steroids and/or radiotherapy, independently of scintigraphic results. At 4 and 24 h after the intravenous injection of 111 MBq of {sup 111}In-pentetreotide, planar imaging centred on the head and neck (anterior and both lateral views) was carried out. Retrobulbar uptake was assessed by visual semi-quantitative analysis (score given by two independent trained observers) and by quantitative analyses (regions of interest, orbit/brain uptake indices). Patients were ophthalmologically followed up for 6 months and then classified as improved or not. Visual semi-quantitative analysis of 4-h/24-h planar images was correlated with the ophthalmological evolution ({chi}{sup 2} test, P<0.01). All ten patients in whom scintigraphy was considered positive were clinically improved at 6 months, and of the seven patients in whom scintigraphy was negative, six were not improved. Nevertheless, objective quantitative analysis did not succeed in confirming these results. We conclude that {sup 111}In-pentetreotide scintigraphy requires further developments, including quantitative single-photon emission tomographic acquisition, if its role as a guide to therapeutic strategy in thyroid-associated ophthalmopathy is to be confirmed

  16. Tumor-associated macrophages in glioblastoma multiforme-a suitable target for somatostatin receptor-based imaging and therapy?

    Directory of Open Access Journals (Sweden)

    Constantin Lapa

    Full Text Available Glioblastoma multiforme (GBM is the most common primary brain tumor in adults. Tumor-associated macrophages (TAM have been shown to promote malignant growth and to correlate with poor prognosis. [1,4,7,10-tetraazacyclododecane-NN',N″,N'″-tetraacetic acid]-d-Phe1,Tyr3-octreotate (DOTATATE labeled with Gallium-68 selectively binds to somatostatin receptor 2A (SSTR2A which is specifically expressed and up-regulated in activated macrophages. On the other hand, the role of SSTR2A expression on the cell surface of glioma cells has not been fully elucidated yet. The aim of this study was to non-invasively assess SSTR2A expression of both glioma cells as well as macrophages in GBM.15 samples of patient-derived GBM were stained immunohistochemically for macrophage infiltration (CD68, proliferative activity (Ki67 as well as expression of SSTR2A. Anti-CD45 staining was performed to distinguish between resident microglia and tumor-infiltrating macrophages. In a subcohort, positron emission tomography (PET imaging using 68Ga-DOTATATE was performed and the semiquantitatively evaluated tracer uptake was compared to the results of immunohistochemistry.The amount of microglia/macrophages ranged from 50% in the tumor samples with the vast majority being resident microglial cells. A strong SSTR2A immunostaining was observed in endothelial cells of proliferating vessels, in neurons and neuropile. Only faint immunostaining was identified on isolated microglial and tumor cells. Somatostatin receptor imaging revealed areas of increased tracer accumulation in every patient. However, retention of the tracer did not correlate with immunohistochemical staining patterns.SSTR2A seems not to be overexpressed in GBM samples tested, neither on the cell surface of resident microglia or infiltrating macrophages, nor on the surface of tumor cells. These data suggest that somatostatin receptor directed imaging and treatment strategies are less promising in GBM.

  17. 99mTc-EDDA/HYNIC-TOC in management of patients with head and neck somatostatin receptor positive tumors.

    Science.gov (United States)

    Trogrlic, Mate; Tezak, Stanko

    2016-01-01

    Aim of this study was to determine the value of technetium-99m-hydrazinonicotinyl-Tyr3-octreotide (99mTc-ED-DA/HYNIC-TOC) in patients with somatostatin receptor (SSR) positive tumors of head and neck region. A total number of 16 patients were enrolled in this study. Planar whole body (WB) and single photon emission computed tomography (SPECT) images were acquired at 2 and 4 hours after the injection of approximately 670 MBq of 99mTc-EDDA/HYNIC-TOC. Additional single photon emission computed tomography/computed tomography (SPECT/CT) images of the head and neck region were acquired at 4h post tracer injection. Clinical and imaging follow up were taken as the reference standard. There were 10 female and 6 male patients of age 57.7 ± 12.9 years (58.5; 32-78) years. 99mTc-EDDA/HYNIC-TOC somatostatin receptor scintigraphy (SRS) was TP in 13 patients, TN in two and FP in one. Follow up period for SRS was 31.1 ± 19.4 (29; 2-63) months. 99mTc-EDDA/HYNIC-TOC scintigraphy provided additional information in 50% of patients, with impact on patient management in the same percentage of patients. Distant metastases were found in nine out of 16 patients (56%). 99mTc-EDDA/HYNIC-TOC SRS had sensitivity of 100% (75.3-100%), specificity of 66.7% (9.4-99.2%), accuracy of 93.7%, positive predictive value of 92.9% (66.1-99.8%), and negative predictive value of 100% (15.8-100%). Somatostatin receptor scintigraphy using 99mTc-EDDA/HYNIC-TOC is very useful imaging method in the evalu-ation of patients with SSR positive tumors of head and neck region.

  18. Hyperglycemia of Diabetic Rats Decreased by a Glucagon Receptor Antagonist

    Science.gov (United States)

    Johnson, David G.; Ulichny Goebel, Camy; Hruby, Victor J.; Bregman, Marvin D.; Trivedi, Dev

    1982-02-01

    The glucagon analog [l-Nα-trinitrophenylhistidine, 12-homoarginine]-glucagon (THG) was examined for its ability to lower blood glucose concentrations in rats made diabetic with streptozotocin. In vitro, THG is a potent antagonist of glucagon activation of the hepatic adenylate cyclase assay system. Intravenous bolus injections of THG caused rapid decreases (20 to 35 percent) of short duration in blood glucose. Continuous infusion of low concentrations of the inhibitor led to larger sustained decreases in blood glucose (30 to 65 percent). These studies demonstrate that a glucagon receptor antagonist can substantially reduce blood glucose levels in diabetic animals without addition of exogenous insulin.

  19. Somatostatin receptor positron emission tomography/computed tomography (PET/CT) in the evaluation of opsoclonus-myoclonus ataxia syndrome

    International Nuclear Information System (INIS)

    Joshi, Prathamesh; Lele, Vikram

    2013-01-01

    Opsoclonus-myoclonus ataxia (OMA) syndrome is the most common paraneoplastic neurological syndrome of childhood, associated with occult neuroblastoma in 20%-50% of all cases. OMA is the initial presentation of neuroblastoma in 1%-3% of children. Conventional radiological imaging approaches include chest radiography and abdominal computed tomography (CT). Nuclear medicine techniques, in form of 123 I/ 131 I-metaiodobenzylguanidine (MIBG) scintigraphy have been incorporated in various diagnostic algorithms for evaluation of OMA. We describe use of somatostatin receptor PET/CT with 68 Gallium- DOTA-DPhe 1 , Tyr 3 -octreotate (DOTATATE) in diagnosis of neuroblastoma in two cases of OMA

  20. Somatostatin receptor positron emission tomography/computed tomography (PET/CT) in the evaluation of opsoclonus-myoclonus ataxia syndrome.

    Science.gov (United States)

    Joshi, Prathamesh; Lele, Vikram

    2013-04-01

    Opsoclonus-myoclonus ataxia (OMA) syndrome is the most common paraneoplastic neurological syndrome of childhood, associated with occult neuroblastoma in 20%-50% of all cases. OMA is the initial presentation of neuroblastoma in 1%-3% of children. Conventional radiological imaging approaches include chest radiography and abdominal computed tomography (CT). Nuclear medicine techniques, in form of (123)I/(131)I-metaiodobenzylguanidine (MIBG) scintigraphy have been incorporated in various diagnostic algorithms for evaluation of OMA. We describe use of somatostatin receptor PET/CT with (68)Gallium- DOTA-DPhe(1), Tyr(3)-octreotate (DOTATATE) in diagnosis of neuroblastoma in two cases of OMA.

  1. Characterization of somatostatin receptors and associated signaling pathways in pancreas of R6/2 transgenic mice.

    Science.gov (United States)

    Somvanshi, Rishi K; Jhajj, Amrit; Heer, Michael; Kumar, Ujendra

    2018-02-01

    The present study describes the status of somatostatin receptors (SSTRs) and their colocalization with insulin (β), glucagon (α) and somatostatin (δ) producing cells in the pancreatic islets of 11weeks old R6/2 Huntington's Disease transgenic (HD tg) and age-matched wild type (wt) mice. We also determined expression of tyrosine hydroxylase (TH), glutamic acid decarboxylase (GAD) and presynaptic marker synaptophysin (SYP) in addition to signal transduction pathways associated with diabetes. In R6/2 mice, islets are relatively smaller in size, exhibit enhanced expression and nuclear inclusion of mHtt along with the loss of insulin, glucagon and somatostatin expression. In comparison to wt, R6/2 mice display enhanced mRNA for all SSTRs except SSTR2. In the pancreatic lysate, SSTR1, 4 and 5 immunoreactivity decreases whereas SSTR3 immunoreactivity increases with no discernible changes in SSTR2 immunoreactivity. Furthermore, at the cellular level, R6/2 mice exhibit a receptor specific distributional pattern of SSTRs like immunoreactivity and colocalization with β, α and δ cells. While GAD expression is increased, TH and SYP immunoreactivity was decreased in R6/2 mice, anticipating a cross-talk between the CNS and pancreas in diabetes pathophysiology. We also dissected out the changes in signaling pathway and found decreased activation and expression of PKA, AKT, ERK1/2 and STAT3 in R6/2 mice pancreas. These findings suggest that the impaired organization of SSTRs within islets may lead to perturbed hormonal regulation and signaling. These interconnected complex events might shed new light on the pathogenesis of diabetes in neurodegenerative diseases and the role of SSTRs in potential therapeutic intervention. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Ga-66 labeled somatostatin analogue DOTA-DPhe1-Tyr3-octreotide as a potential agent for positron emission tomography imaging and receptor mediated internal radiotherapy of somatostatin receptor positive tumors

    International Nuclear Information System (INIS)

    Ugur, Oemer; Kothari, Paresh J.; Finn, Ronald D.; Zanzonico, Pat; Ruan, Shutian; Guenther, Ilonka; Maecke, Helmut R.; Larson, Steven M.

    2002-01-01

    Radionuclide labeled somatostatin analogues selectively target somatostatin receptor (SSTR)-expressing tumors as a basis for diagnosis and treatment of these tumors. Recently, a DOTA-functionalized somatostatin analogue, DOTATOC (DOTA-DPhe 1 -Tyr 3 -octreotide) has been developed. This compound has been shown to be superior to the other somatostatin analogues as indicated by its uniquely high tumor-to-non-target tissue ratio. DOTATOC can be labeled with a variety of radiometals including gallium radioisotopes. Gallium-66 is a positron emitting radionuclide (T 1/2 =9.5 hr; β + =56%), that can be produced in carrier free form by a low-beam energy cyclotron. In this study we investigated SSTR targeting characteristics of 66 Ga-DOTATOC in AR42J rat pancreas tumor implanted nude mice as a potential agent for diagnosis and receptor-mediated internal radiotherapy of SSTR-expressing tumors. We compared our results with 67 Ga- and 68 Ga- labeled DOTATOC. The radiolabeling procedure gave labeling yield ranged from 85-95% and radiochemical and chemical purity was >95%. In-vitro competitive binding curves and in-vivo competitive displacement studies with an excess of unlabeled peptide indicates that there is specific binding of the radioligand to SSTR. Animal biodistribution data and serial microPET TM images demonstrated rapid tumor uptake and rapid clearance from the blood and all tissues except kidney. Maximum % ID/g values for tumor were 10.0±0.7, 13.2±2.1 and 9.8±1.5 for 66 Ga-, 67 Ga-, and 68 Ga-DOTATOC, respectively. Calculated tumor, kidney and bone marrow doses for 66 Ga-DOTATOC based on biodistribution data were 178, 109 and 1.2 cGy/MBq, respectively. We conclude that 66 Ga labeled DOTATOC can be used for PET diagnosis and quantitative imaging-based dosimetry of SSTR positive tumors. 66 Ga-DOTATOC may also be used in higher doses for ablation of these tumors. However, kidney is the critical organ for toxicity (tumor/kidney ratio 1.64), and high kidney uptake must

  3. Ga-66 labeled somatostatin analogue DOTA-DPhe{sup 1}-Tyr{sup 3}-octreotide as a potential agent for positron emission tomography imaging and receptor mediated internal radiotherapy of somatostatin receptor positive tumors

    Energy Technology Data Exchange (ETDEWEB)

    Ugur, Oemer E-mail: ougur@hacettepe.edu.tr; Kothari, Paresh J.; Finn, Ronald D.; Zanzonico, Pat; Ruan, Shutian; Guenther, Ilonka; Maecke, Helmut R.; Larson, Steven M

    2002-02-01

    Radionuclide labeled somatostatin analogues selectively target somatostatin receptor (SSTR)-expressing tumors as a basis for diagnosis and treatment of these tumors. Recently, a DOTA-functionalized somatostatin analogue, DOTATOC (DOTA-DPhe{sup 1}-Tyr{sup 3}-octreotide) has been developed. This compound has been shown to be superior to the other somatostatin analogues as indicated by its uniquely high tumor-to-non-target tissue ratio. DOTATOC can be labeled with a variety of radiometals including gallium radioisotopes. Gallium-66 is a positron emitting radionuclide (T{sub 1/2} =9.5 hr; {beta}{sup +}=56%), that can be produced in carrier free form by a low-beam energy cyclotron. In this study we investigated SSTR targeting characteristics of {sup 66}Ga-DOTATOC in AR42J rat pancreas tumor implanted nude mice as a potential agent for diagnosis and receptor-mediated internal radiotherapy of SSTR-expressing tumors. We compared our results with {sup 67}Ga- and {sup 68}Ga- labeled DOTATOC. The radiolabeling procedure gave labeling yield ranged from 85-95% and radiochemical and chemical purity was >95%. In-vitro competitive binding curves and in-vivo competitive displacement studies with an excess of unlabeled peptide indicates that there is specific binding of the radioligand to SSTR. Animal biodistribution data and serial microPET{sup TM} images demonstrated rapid tumor uptake and rapid clearance from the blood and all tissues except kidney. Maximum % ID/g values for tumor were 10.0{+-}0.7, 13.2{+-}2.1 and 9.8{+-}1.5 for {sup 66}Ga-, {sup 67}Ga-, and {sup 68}Ga-DOTATOC, respectively. Calculated tumor, kidney and bone marrow doses for {sup 66}Ga-DOTATOC based on biodistribution data were 178, 109 and 1.2 cGy/MBq, respectively. We conclude that {sup 66}Ga labeled DOTATOC can be used for PET diagnosis and quantitative imaging-based dosimetry of SSTR positive tumors. {sup 66}Ga-DOTATOC may also be used in higher doses for ablation of these tumors. However, kidney is the

  4. Transcriptional and Functional Characterization of the G Protein-Coupled Receptor Repertoire of Gastric Somatostatin Cells

    DEFF Research Database (Denmark)

    Egerod, Kristoffer L; Engelstoft, Maja S; Lund, Mari L

    2015-01-01

    In the stomach, somatostatin (SST) acts as a general paracrine negative regulator of exocrine secretion of gastric acid and pepsinogen and endocrine secretion of gastrin, ghrelin, and histamine. Using reporter mice expressing red fluorescent protein (RFP) under control of the SST promotor, we hav...

  5. Interleukin-1-receptor antagonist in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Larsen, Claus M; Faulenbach, Mirjam; Vaag, Allan

    2007-01-01

    BACKGROUND: The expression of interleukin-1-receptor antagonist is reduced in pancreatic islets of patients with type 2 diabetes mellitus, and high glucose concentrations induce the production of interleukin-1beta in human pancreatic beta cells, leading to impaired insulin secretion, decreased cell...... proliferation, and apoptosis. METHODS: In this double-blind, parallel-group trial involving 70 patients with type 2 diabetes, we randomly assigned 34 patients to receive 100 mg of anakinra (a recombinant human interleukin-1-receptor antagonist) subcutaneously once daily for 13 weeks and 36 patients to receive...... placebo. At baseline and at 13 weeks, all patients underwent an oral glucose-tolerance test, followed by an intravenous bolus of 0.3 g of glucose per kilogram of body weight, 0.5 mg of glucagon, and 5 g of arginine. In addition, 35 patients underwent a hyperinsulinemic-euglycemic clamp study. The primary...

  6. Acute up-regulation of the rat brain somatostatin receptor-effector system by leptin is related to activation of insulin signaling and may counteract central leptin actions.

    Science.gov (United States)

    Perianes-Cachero, A; Burgos-Ramos, E; Puebla-Jiménez, L; Canelles, S; Frago, L M; Hervás-Aguilar, A; de Frutos, S; Toledo-Lobo, M V; Mela, V; Viveros, M P; Argente, J; Chowen, J A; Arilla-Ferreiro, E; Barrios, V

    2013-11-12

    Leptin and somatostatin (SRIF) have opposite effects on food seeking and ingestive behaviors, functions partially regulated by the frontoparietal cortex and hippocampus. Although it is known that the acute suppression of food intake mediated by leptin decreases with time, the counter-regulatory mechanisms remain unclear. Our aims were to analyze the effect of acute central leptin infusion on the SRIF receptor-effector system in these areas and the implication of related intracellular signaling mechanisms in this response. We studied 20 adult male Wister rats including controls and those treated intracerebroventricularly with a single dose of 5 μg of leptin and sacrificed 1 or 6h later. Density of SRIF receptors was unchanged at 1h, whereas leptin increased the density of SRIF receptors at 6h, which was correlated with an elevated capacity of SRIF to inhibit forskolin-stimulated adenylyl cyclase activity in both areas. The functional capacity of SRIF receptors was unaltered as cell membrane levels of αi1 and αi2 subunits of G inhibitory proteins were unaffected in both brain areas. The increased density of SRIF receptors was due to enhanced SRIF receptor subtype 2 (sst2) protein levels that correlated with higher mRNA levels for this receptor. These changes in sst2 mRNA levels were concomitant with increased activation of the insulin signaling, c-Jun and cyclic AMP response element-binding protein (CREB); however, activation of signal transducer and activator of transcription 3 was reduced in the cortex and unchanged in the hippocampus and suppressor of cytokine signaling 3 remained unchanged in these areas. In addition, the leptin antagonist L39A/D40A/F41A blocked the leptin-induced changes in SRIF receptors, leptin signaling and CREB activation. In conclusion, increased activation of insulin signaling after leptin infusion is related to acute up-regulation of the SRIF receptor-effector system that may antagonize short-term leptin actions in the rat brain

  7. Impact of the scintigraphy of somatostatin receptors upon the therapeutic strategy in patients bearing digestive endocrine tumors

    International Nuclear Information System (INIS)

    Lebtahi, R.; Cadiot, G.; Genin, R.; Delahaye, N.; Faraggi, M.; Daou, D.; Peker, C.; Migon, M.; Le Guludec, D.

    1997-01-01

    The scintigraphy of somatostatin receptors (SSR) is a sensible method for detecting the gastroenteric-pancreatic endocrine tumors and their metastases. The aim of this study is to evaluate the clinical impact of the results of SSR in taking patients in therapeutic charge. A hundred and sixty patients bearing biologically and/or histologically proved digestive endocrine tumors were prospectively studied. The patients were classified in 3 groups: group I - 90 patients with no known metastases; group II - 59 patients with liver metastases and group III - 11 patients with known extra-hepatic metastases. The results of the scintigraphy were compared with those of conventional imaging. The following results were obtained: in group 1 (90 patients) the conventional imaging has allowed detecting 53 primitive tumors in 44 patients. The SSR visualized 68% of these sites and has detected 26 supplementary primitive sites in 20 patients and 29 metastatic sites in 25 patients. In group II the scintigraphy has detected 95% of hepatic metastases and revealed 23 new metastasis sites and 18/59 patients. In group III the scintigraphy has detected 11 new sites in 7 patients. The results of scintigraphy modified the patient's classification in 38 cases (24%). The therapeutic strategy was modified for 40 patients (25%). In conclusion, the scintigraphy of somatostatin receptors is able to detect a significant number of digestive endocrine tumors what has important implications for therapeutical planning of the treatment of patients. It must be carried out during pre-therapeutic extension examination of these tumors

  8. Normal uptake of 68Ga-DOTA-TOC by the pancreas uncinate process mimicking malignancy at somatostatin receptor PET.

    Science.gov (United States)

    Jacobsson, Hans; Larsson, Patricia; Jonsson, Cathrine; Jussing, Emma; Grybäck, Per

    2012-04-01

    To characterize a commonly occurring increased uptake by the uncinate process of the pancreas at PET/CT using 68Ga-DOTA-d-Phe1-Tyr3-octreotide (68Ga-DOTA-TOC). This tracer has replaced In pentetreotide (OctreoScan®) for somatostatin receptor scintigraphy at our laboratory. Fifty of our first 74 PET/CT examinations with 68Ga-DOTA-TOC could be evaluated in retrospect. None of these patients had surgery or showed any pathology in the pancreas head at the concomitant CT. Thirty-five of the 50 examinations (70%) showed an uptake by the uncinate process sufficiently intense to be interpreted as pathologic and simulating a tumor. Mean SUVmax was 9.2. Mean SUVmean using an isoactivity cut-off of >75% and >50% was 7.8 and 6.0, respectively. Volume calculations of the uncinate process activity using these definitions gave 0.9 mL and 4.2 mL, respectively. There is a frequent physiological uptake of 68Ga-DOTA-TOC by the pancreas uncinate process. This may be caused by an accumulation of pancreatic polypeptide-containing cells expressing somatostatin receptors. If there is a normal finding at concomitant diagnostic CT, this uptake should be regarded as physiological.

  9. The influence of somatostatin receptor scintigraphy during preoperative staging of non-functioning pancreatic neuroendocrine tumours

    International Nuclear Information System (INIS)

    Jilesen, A.P.J.; Hoefnagel, S.J.M.; Busch, O.R.C.; Bennink, R.J.; Gouma, D.J.; Nieveen van Dijkum, E.J.M.

    2016-01-01

    Aim: To determine whether somatostatin receptor scintigraphy (SRS) influences the preoperative staging and clinical management of non-functioning pancreatic neuroendocrine tumours (NF-pNETs). Materials and methods: All SRS examinations performed between 2002–2013 were selected. Patients with NF-pNET were included if both computed tomography (CT) and SRS was performed during preoperative staging. The diagnostic accuracy of CT and SRS for detecting NF-pNET metastases was analysed. Altered TNM classification and changed clinical management were calculated. Changed management was defined as a change from surgical resection into systemic treatment or vice versa. NF-pNETs were defined as tumours without clinical symptoms of hormonal hypersecretion. Results: Overall, 62 patients with NF-pNET were included with a mean age of 57 years (SD: 12.4) 2 . In 28 patients (45%), CT and SRS were correct and in agreement in the detection of primary tumour/metastases. In 34 patients (55%), one of the techniques was incorrect and therefore, there was no agreement. SRS altered the TNM classification in 14 patients (23%) and clinical management in nine patients (15%). In patients without metastases on CT, SRS detected lymph node metastases in one patient. The sensitivity to detect the primary tumour with CT was 95% and with SRS was 73%. In detecting metastases, the sensitivity and specificity were both 85% for CT versus 80% and 90% for SRS. Conclusion: Overall, CT and SRS were in agreement in the detection of NF-pNET. In NF-pNET without suspicious metastatic lesions on CT, SRS has limited value. SRS may be indicated to confirm lesions suspicious for neuroendocrine tumours metastases. - Highlights: • In 28 patients (45%), CT and SRS were correct and in agreement in the detection of primary tumor/metastases. • In 34 patients (55%) one of the modalities was incorrect and therefore, there was no agreement. • Sensitivity to detect the primary tumor with CT and SRS were 95% versus 73

  10. The discovery of tropane-derived CCR5 receptor antagonists.

    Science.gov (United States)

    Armour, Duncan R; de Groot, Marcel J; Price, David A; Stammen, Blanda L C; Wood, Anthony; Perros, Manos; Burt, Catherine

    2006-04-01

    The development of compound 1, a piperidine-based CCR5 receptor antagonist with Type I CYP2D6 inhibition, into the tropane-derived analogue 5, is described. This compound, which is devoid of CYP2D6 liabilities, is a highly potent ligand for the CCR5 receptor and has broad-spectrum activity against a range of clinically relevant HIV isolates. The identification of human ether a-go-go-related gene channel inhibition within this series is described and the potential for QTc interval prolongation discussed. Furthermore, structure activity relationship (SAR) around the piperidine moiety is also described.

  11. Somatostatin receptor scintigraphy using 99mTc-EDDA/HYNIC-TOC in patients with medullary thyroid carcinoma.

    Science.gov (United States)

    Czepczyński, Rafał; Parisella, Maria Gemma; Kosowicz, Jerzy; Mikołajczak, Renata; Ziemnicka, Katarzyna; Gryczyńska, Maria; Sowiński, Jerzy; Signore, Alberto

    2007-10-01

    Several new somatostatin analogues have been developed for the diagnosis and therapy of different tumours. Since somatostatin receptors are often over-expressed in medullary thyroid carcinoma (MTC), the aim of our study was to evaluate the utility of scintigraphy with the somatostatin analogue (99m)Tc-EDDA/HYNIC-TOC in MTC in comparison with other diagnostic techniques. Forty-five patients with MTC, aged 14-83 years, were investigated. Scintigraphy using (99m)Tc-EDDA/HYNIC-TOC (Tektrotyd) was performed 2 and 4 h post injection of 740 MBq (20 mCi) of the tracer. Other imaging techniques were also applied and analysed in individual cases (ultrasonography, computed tomography, (99m)Tc(V)-DMSA, (131)I-MIBG, (99m)Tc-MDP, (111)In-DTPA-octreotide and (18)F-FDG-PET) and compared with (99m)Tc-EDDA/HYNIC-TOC. In group 1 (eight patients before thyroidectomy), uptake of the tracer was found in the primary tumours. In group 2 (six patients with remission), a false positive result was found in one patient; in the remaining five patients, no pathological foci were visualised. In group 3 (31 patients with post-surgical hypercalcitoninaemia), scintigraphy was true positive in 23 patients (74.2%): uptake in the thyroid bed was found in five patients, in the lymph nodes in 18 and in bone metastases in four. Using (99m)Tc-EDDA/HYNIC-TOC scintigraphy, the overall sensitivity was 79.5%, specificity 83.3%, accuracy 80.0%, positive predictive value 96.9% and negative predictive value 38.5%. (99m)Tc-EDDA/HYNIC-TOC is clinically useful for scintigraphy in the follow-up of patients with MTC. It can be used in clinical practice for preoperative evaluation, for localisation of local recurrence or distant metastases and particularly for therapy decision making.

  12. Somatostatin receptor scintigraphy using 99mTc-EDDA/HYNIC-TOC in patients with medullary thyroid carcinoma

    International Nuclear Information System (INIS)

    Czepczynski, Rafal; Kosowicz, Jerzy; Ziemnicka, Katarzyna; Gryczynska, Maria; Sowinski, Jerzy; Parisella, Maria G.; Mikolajczak, Renata; Signore, Alberto

    2007-01-01

    Several new somatostatin analogues have been developed for the diagnosis and therapy of different tumours. Since somatostatin receptors are often over-expressed in medullary thyroid carcinoma (MTC), the aim of our study was to evaluate the utility of scintigraphy with the somatostatin analogue 99m Tc-EDDA/HYNIC-TOC in MTC in comparison with other diagnostic techniques. Forty-five patients with MTC, aged 14-83 years, were investigated. Scintigraphy using 99m Tc-EDDA/HYNIC-TOC (Tektrotyd) was performed 2 and 4 h post injection of 740 MBq (20 mCi) of the tracer. Other imaging techniques were also applied and analysed in individual cases (ultrasonography, computed tomography, 99m Tc(V)-DMSA, 131 I-MIBG, 99m Tc-MDP, 111 In-DTPA-octreotide and 18 F-FDG-PET) and compared with 99m Tc-EDDA/HYNIC-TOC. In group 1 (eight patients before thyroidectomy), uptake of the tracer was found in the primary tumours. In group 2 (six patients with remission), a false positive result was found in one patient; in the remaining five patients, no pathological foci were visualised. In group 3 (31 patients with post-surgical hypercalcitoninaemia), scintigraphy was true positive in 23 patients (74.2%): uptake in the thyroid bed was found in five patients, in the lymph nodes in 18 and in bone metastases in four. Using 99m Tc-EDDA/HYNIC-TOC scintigraphy, the overall sensitivity was 79.5%, specificity 83.3%, accuracy 80.0%, positive predictive value 96.9% and negative predictive value 38.5%. 99m Tc-EDDA/HYNIC-TOC is clinically useful for scintigraphy in the follow-up of patients with MTC. It can be used in clinical practice for preoperative evaluation, for localisation of local recurrence or distant metastases and particularly for therapy decision making. (orig.)

  13. Characterization of a novel non-steroidal glucocorticoid receptor antagonist

    Energy Technology Data Exchange (ETDEWEB)

    Li, Qun-Yi; Zhang, Meng [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Hallis, Tina M.; DeRosier, Therese A. [Cell Systems Division, Invitrogen, Madison, WI (United States); Yue, Jian-Min; Ye, Yang [State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China); Mais, Dale E. [The National Center for Drug Screening, Shanghai (China); MPI Research, Mattawan, MI (United States); Wang, Ming-Wei, E-mail: wangmw@mail.shcnc.ac.cn [The National Center for Drug Screening, Shanghai (China); State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai (China)

    2010-01-15

    Selective antagonists of the glucocorticoid receptor (GR) are desirable for the treatment of hypercortisolemia associated with Cushing's syndrome, psychic depression, obesity, diabetes, neurodegenerative diseases, and glaucoma. NC3327, a non-steroidal small molecule with potent binding affinity to GR (K{sub i} = 13.2 nM), was identified in a high-throughput screening effort. As a full GR antagonist, NC3327 greatly inhibits the dexamethasone (Dex) induction of marker genes involved in hepatic gluconeogenesis, but has a minimal effect on matrix metalloproteinase 9 (MMP-9), a GR responsive pro-inflammatory gene. Interestingly, the compound recruits neither coactivators nor corepressors to the GR complex but competes with glucocorticoids for the interaction between GR and a coactivator peptide. Moreover, NC3327 does not trigger GR nuclear translocation, but significantly blocks Dex-induced GR transportation to the nucleus, and thus appears to be a 'competitive' GR antagonist. Therefore, the non-steroidal compound, NC3327, may represent a new class of GR antagonists as potential therapeutics for a variety of cortisol-related endocrine disorders.

  14. Characterization of a novel non-steroidal glucocorticoid receptor antagonist

    International Nuclear Information System (INIS)

    Li, Qun-Yi; Zhang, Meng; Hallis, Tina M.; DeRosier, Therese A.; Yue, Jian-Min; Ye, Yang; Mais, Dale E.; Wang, Ming-Wei

    2010-01-01

    Selective antagonists of the glucocorticoid receptor (GR) are desirable for the treatment of hypercortisolemia associated with Cushing's syndrome, psychic depression, obesity, diabetes, neurodegenerative diseases, and glaucoma. NC3327, a non-steroidal small molecule with potent binding affinity to GR (K i = 13.2 nM), was identified in a high-throughput screening effort. As a full GR antagonist, NC3327 greatly inhibits the dexamethasone (Dex) induction of marker genes involved in hepatic gluconeogenesis, but has a minimal effect on matrix metalloproteinase 9 (MMP-9), a GR responsive pro-inflammatory gene. Interestingly, the compound recruits neither coactivators nor corepressors to the GR complex but competes with glucocorticoids for the interaction between GR and a coactivator peptide. Moreover, NC3327 does not trigger GR nuclear translocation, but significantly blocks Dex-induced GR transportation to the nucleus, and thus appears to be a 'competitive' GR antagonist. Therefore, the non-steroidal compound, NC3327, may represent a new class of GR antagonists as potential therapeutics for a variety of cortisol-related endocrine disorders.

  15. Induction of Human Somatostatin Receptor Subtype 2 on Breast Tumors with an Adenoviral Vector for Their Treatment and Detection with a Radiolabeled Peptide

    National Research Council Canada - National Science Library

    Rogers, Buck

    2002-01-01

    .... An adenoviral vector encoding the human somatostatin receptor subtype 2 (AdSSTr2) has been produced. The MDA- MB-468 and BT-474 human breast cancer cells were infected with AdSSTr2 and harvested 48 h later for membrane preparations...

  16. Potential Clinical Implications of the Urotensin II Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Emilie Kane

    2011-07-01

    Full Text Available Urotensin-II (UII, which binds to its receptor UT, plays an important role in the heart, kidneys, pancreas, adrenal gland and CNS. In the vasculature, it acts as a potent endothelium-independent vasoconstrictor and endothelium-dependent vasodilator. In disease states, this constriction-dilation equilibrium is disrupted. There is an upregulation of the UII system in heart disease, metabolic syndrome and kidney failure. The increase in UII release and UT expression suggest that UII system may be implicated in the pathology and pathogenesis of these diseases by causing an increase in ACAT-1 activity leading to SMC proliferation and foam cell infiltration, insulin resistance (DMII, as well as inflammation, high blood pressure and plaque formation. Recently, UT antagonists such as SB-611812, palosuran, and most recently a piperazino-isoindolinone based antagonist have been developed in the hope of better understanding the UII system and treating its associated diseases.

  17. Carbobenzoxy amino acids: Structural requirements for cholecystokinin receptor antagonist activity

    International Nuclear Information System (INIS)

    Maton, P.N.; Sutliff, V.E.; Jensen, R.T.; Gardner, J.D.

    1985-01-01

    The authors used dispersed acini prepared from guinea pig pancreas to examine 28 carbobenzoxy (CBZ) amino acids for their abilities to function as cholecystokinin receptor antagonists. All amino acid derivatives tested, except for CBZ-alanine, CBZ-glycine, and N alpha-CBZ- lysine, were able to inhibit the stimulation of amylase secretion caused by the C-terminal octapeptide of cholecystokinin. In general, there was a good correlation between the ability of a carbobenzoxy amino acid to inhibit stimulated amylase secretion and the ability of the amino acid derivative to inhibit binding of 125 I-cholecystokinin. The inhibition of cholecystokinin-stimulated amylase secretion was competitive, fully reversible, and specific for those secretagogues that interact with the cholecystokinin receptor. The potencies with which the various carbobenzoxy amino acids inhibited the action of cholecystokinin varied 100-fold and CBZ-cystine was the most potent cholecystokinin receptor antagonist. This variation in potency was primarily but not exclusively a function of the hydrophobicity of the amino acid side chain

  18. The somatostatin receptor-targeted radiotherapeutic [90Y-DOTA-dPhe1,Tyr3]octreotide (90Y-SMT 487) eradicates experimental rat pancreatic CA 20948 tumours

    International Nuclear Information System (INIS)

    Stolz, B.; Weckbecker, G.; Smith-Jones, P.M.; Albert, R.; Raulf, F.; Bruns, C.

    1998-01-01

    Somatostatin receptor-expressing tumours are potential targets for therapy with radiolabelled somatostatin analogues. We have synthesized a number of such analogues in the past and identified [DOTA-dPhe 1 , Tyr 3 ]octreotide (SMT 487) as the most promising candidate molecule because of its advantageous properties in cellular and in vivo tumour models. In the current paper we describe the radiotherapeutic effect of yttrium-90 labelled SMT 487 in Lewis rats bearing the somatostatin receptor-positive rat pancreatic tumour CA 20948. SMT 487 binds with nanomolar affinity to both the human and the rat somatostatin receptor subtype 2 (sst 2 ) (human sst 2 IC 50 =0.9 nM, rat sst 2 IC 50 =0.5 nM). In vivo, 90 Y-SMT 487 distributed rapidly to the sst 2 expressing CA 20948 rat pancreatic tumour, with a tumour-to-blood ratio of 49.15 at 24 h post injection. A single intravenous administration of 10 mCi/kg 90 Y-SMT 487 resulted in a complete remission of the tumours in five out of seven CA 20948 tumour-bearing Lewis rats. No regrowth of the tumours occurred 8 months post injection. Control animals that were treated with 30 μg/kg of unlabelled SMT 487 had to be sacrificed 10 days post injection due to excessive growth or necrotic areas on the tumour surface. Upon re-inoculation of tumour cells into those rats that had shown complete remission, the tumours disappeared after 3-4 weeks of moderate growth without any further treatment. The present study shows for the first time the curative potential of 90 Y-SMT 487-based radiotherapy for somatostatin receptor-expressing tumours. Clinical phase I studies with yttrium-labelled SMT 487 have started in September 1997. (orig.)

  19. Expression of somatostatin receptors subtype 2 and 5 in extraocular muscle tissue of hypothyroidism animal induced by 131I

    International Nuclear Information System (INIS)

    Li Fangdu; Chu Qiaomei; Xu Peikang; Yao Xiaohong; Shen Jiangfan

    2012-01-01

    Objective: To observe the expression and distribution of somatostatin receptors 2 and 5 (SSTR2, 5) in extraocular muscle in hypothyroidism and thyroid associated ophthalmopathy (TAO) Wister rats induced by 131 I. Methods: 20 Wister rats were randomly divided into experimental group and normal group(group D). According to 131 I doses of intraperitoneal injection, the experimental groups were divided into low (group A), middle (group B) and high dose group (group C). After 8 weeks, all rats were sacrificed and orbital tissue sections were applied to HE staining and Immunohistochemistry for the analysis of rat orbital tissue changes and SSTR2 and 5 distribution in extraocular muscle. Results: The serum FT 4 levels in group A (16.98±2.92 pmol / L), group B (1.84±0.44 pmol / L) and group C (1.35 ±0.37 pmol /L) eight weeks after 131 I injection were decreased, and had significant difference compared with group D (P 4 levels in group B and C were significantly lower than that in group A (P 0.05). Orbital tissue in experimental group showed mucoid degeneration and edema, the extent was about 25% in group A, 50% in group B, 70% in group C. The rats in group B and group C appeared obvious proliferation of fibrous and adipose tissue, muscle fibers degeneration fracture, even extraocular muscles in group C have vacuole formation. Immunohistochemical analysis displayed highest SSTR5 distribution and strongest expression was in extraocular muscle of group C, second in A B combination group (A and B groups)and weakest in group D. There were significant differences between A B combination group,group C and group D (P 0.05). Conclusion: This study observed the distribution and expression of SSTR2 and SSTR5 in extraocular muscle on the established hypothyroidism animal model. It is some significance for understanding the mechanism of somatostatin receptors in occurrence and development of TAO, similar to provide a reference for the use of somatostatin analogue orbital imaging

  20. Evaluation of somatostatin receptors in large cell pulmonary neuroendocrine carcinoma with 99mTc-EDDA/HYNIC-TOC scintigraphy.

    Science.gov (United States)

    Nocuń, Anna; Chrapko, Beata; Gołębiewska, Renata; Stefaniak, Bogusław; Czekajska-Chehab, Elżbieta

    2011-06-01

    Large cell pulmonary neuroendocrine carcinoma (LCNEC) is a poorly differentiated and high-grade neoplasm. It is positioned between an atypical carcinoid and small cell neuroendocrine carcinoma of the lung in a distinct family of pulmonary neuroendocrine tumors. The aim of our study was to detect somatostatin receptors in this uncommon malignancy and to evaluate the sensitivity of somatostatin receptor scintigraphy (SRS) in LCNEC staging. We analyzed data of 26 patients (mean age: 61.5±7.9 years) with histologically confirmed diagnosis of LCNEC, including 18 cases not treated surgically and eight patients after the resection of the primary tumor. SRS was carried out with technetium-99m ethylene diamine-diacetic acid/hydrazinonicotinyl-Tyr3-octreotide (Tc-TOC). A visual analysis of scintigraphic images was done with reference to conventional imaging modalities (computed tomography and bone sicintigraphy). SRS sensitivity for the detection of primary lesions, supradiaphragmatic metastases, and infradiaphragmatic metastases was 100, 83.3%, and 0%, respectively. Five out of 13 metastases to the liver appeared on SRS as photopenic foci, visible on the background of physiological hepatic activity. Only one of the nine metastases to the skeletal system was found by SRS with sensitivity as low as 11.1%. The overall SRS sensitivity for the detection of secondary lesions and of all lesions was 54.8 and 62.2%, respectively. Within a rather large series of LCNEC, the primary tumor showed an uptake of Tc-TOC in all cases, whereas some metastases did show Tc-TOC uptake and some others did not.

  1. Correlation of Somatostatin Receptor-2 Expression with Gallium-68-DOTA-TATE Uptake in Neuroblastoma Xenograft Models.

    Science.gov (United States)

    Zhang, Libo; Vines, Douglass C; Scollard, Deborah A; McKee, Trevor; Komal, Teesha; Ganguly, Milan; Do, Trevor; Wu, Bing; Alexander, Natasha; Vali, Reza; Shammas, Amer; Besanger, Travis; Baruchel, Sylvain

    2017-01-01

    Peptide-receptor imaging and therapy with radiolabeled somatostatin analogs such as 68 Ga-DOTA-TATE and 177 Lu-DOTA-TATE have become an effective treatment option for SSTR-positive neuroendocrine tumors. The purpose of this study was to evaluate the correlation of somatostatin receptor-2 (SSTR2) expression with 68 Ga-DOTA-TATE uptake and 177 Lu-DOTA-TATE therapy in neuroblastoma (NB) xenograft models. We demonstrated variable SSTR2 expression profiles in eight NB cell lines. From micro-PET imaging and autoradiography, a higher uptake of 68 Ga-DOTA-TATE was observed in SSTR2 high-expressing NB xenografts (CHLA-15) compared to SSTR2 low-expressing NB xenografts (SK-N-BE(2)). Combined autoradiography-immunohistochemistry revealed histological colocalization of SSTR2 and 68 Ga-DOTA-TATE uptake in CHLA-15 tumors. With a low dose of 177 Lu-DOTA-TATE (20 MBq/animal), tumor growth inhibition was achieved in the CHLA-15 high SSTR2 expressing xenograft model. Although, in vitro , NB cells showed variable expression levels of norepinephrine transporter (NET), a molecular target for 131 I-MIBG therapy, low 123 I-MIBG uptake was observed in all selected NB xenografts. In conclusion, SSTR2 expression levels are associated with 68 Ga-DOTA-TATE uptake and antitumor efficacy of 177 Lu-DOTA-TATE. 68 Ga-DOTA-TATE PET is superior to 123 I-MIBG SPECT imaging in detecting NB tumors in our model. Radiolabeled DOTA-TATE can be used as an agent for NB tumor imaging to potentially discriminate tumors eligible for 177 Lu-DOTA-TATE therapy.

  2. Correlation of Somatostatin Receptor-2 Expression with Gallium-68-DOTA-TATE Uptake in Neuroblastoma Xenograft Models

    Directory of Open Access Journals (Sweden)

    Libo Zhang

    2017-01-01

    Full Text Available Peptide-receptor imaging and therapy with radiolabeled somatostatin analogs such as 68Ga-DOTA-TATE and 177Lu-DOTA-TATE have become an effective treatment option for SSTR-positive neuroendocrine tumors. The purpose of this study was to evaluate the correlation of somatostatin receptor-2 (SSTR2 expression with 68Ga-DOTA-TATE uptake and 177Lu-DOTA-TATE therapy in neuroblastoma (NB xenograft models. We demonstrated variable SSTR2 expression profiles in eight NB cell lines. From micro-PET imaging and autoradiography, a higher uptake of 68Ga-DOTA-TATE was observed in SSTR2 high-expressing NB xenografts (CHLA-15 compared to SSTR2 low-expressing NB xenografts (SK-N-BE(2. Combined autoradiography-immunohistochemistry revealed histological colocalization of SSTR2 and 68Ga-DOTA-TATE uptake in CHLA-15 tumors. With a low dose of 177Lu-DOTA-TATE (20 MBq/animal, tumor growth inhibition was achieved in the CHLA-15 high SSTR2 expressing xenograft model. Although, in vitro, NB cells showed variable expression levels of norepinephrine transporter (NET, a molecular target for 131I-MIBG therapy, low 123I-MIBG uptake was observed in all selected NB xenografts. In conclusion, SSTR2 expression levels are associated with 68Ga-DOTA-TATE uptake and antitumor efficacy of 177Lu-DOTA-TATE. 68Ga-DOTA-TATE PET is superior to 123I-MIBG SPECT imaging in detecting NB tumors in our model. Radiolabeled DOTA-TATE can be used as an agent for NB tumor imaging to potentially discriminate tumors eligible for 177Lu-DOTA-TATE therapy.

  3. Toxicological Differences Between NMDA Receptor Antagonists and Cholinesterase Inhibitors.

    Science.gov (United States)

    Shi, Xiaodong; Lin, Xiaotian; Hu, Rui; Sun, Nan; Hao, Jingru; Gao, Can

    2016-08-01

    Cholinesterase inhibitors (ChEIs), represented by donepezil, rivastigmine, and galantamine, used to be the only approved class of drugs for the treatment of Alzheimer's disease. After the approval of memantine by the Food and Drug Administration (FDA), N-methyl-d-aspartic acid (NMDA) receptor antagonists have been recognized by authorities and broadly used in the treatment of Alzheimer's disease. Along with complementary mechanisms of action, NMDA antagonists and ChEIs differ not only in therapeutic effects but also in adverse reactions, which is an important consideration in clinical drug use. And the number of patients using NMDA antagonists and ChEIs concomitantly has increased, making the matter more complicated. Here we used the FDA Adverse Event Reporting System for statistical analysis , in order to compare the adverse events of memantine and ChEIs. In general, the clinical evidence confirmed the safety advantages of memantine over ChEIs, reiterating the precautions of clinical drug use and the future direction of antidementia drug development. © The Author(s) 2016.

  4. Effect of Peptide Receptor Radionuclide Therapy on Somatostatin Receptor Status and Glucose Metabolism in Neuroendocrine Tumors: Intraindividual Comparison of Ga-68 DOTANOC PET/CT and F-18 FDG PET/CT

    Science.gov (United States)

    Oh, Sowon; Prasad, Vikas; Lee, Dong Soo; Baum, R. P.

    2011-01-01

    The heterogeneous nature of the neuroendocrine tumors (NET) makes it challenging to find one uniformly applicable management protocol which is especially true for diagnosis. The discovery of the overexpression of somatostatin receptors (SMS-R) on neuroendocrine tumor cells lead to the generalized and rapid acceptance of radiolabeled somatostatin receptor analogs for staging and restaging of NET as well as for Peptide Receptor Radionuclide Therapy (PRRNT) using Y-90 and Lu-177 DOTATATE/DOTATOC. In this present work we tried to look in to the effect of PRRNT on the glucose metabolism assessed by F-18 FDG PET/CT and SMS-R density assessed by Ga-68 DOTANOC PET/CT. We observed a complex relationship between the somatostatin receptor expression and glucose metabolism with only 56% (77/138) of the lesions showing match, while the others show mismatch between the receptor status and metabolism. The match between receptor expression and glucose metabolism increases with the grade of NET. In grade 3 NET, there is a concurrence between the changes in glucose metabolism and somatostatin receptor expression. PRRNT was found to be more effective in lesions with higher receptor expression. PMID:22121482

  5. Evodiamine as a novel antagonist of aryl hydrocarbon receptor

    International Nuclear Information System (INIS)

    Yu, Hui; Tu, Yongjiu; Zhang, Chun; Fan, Xia; Wang, Xi; Wang, Zhanli; Liang, Huaping

    2010-01-01

    Research highlights: → Evodiamine interacted with the AhR. → Evodiamine inhibited the specific binding of [ 3 H]-TCDD to the AhR. → Evodiamine acts as an antagonist of the AhR. -- Abstract: Evodiamine, the major bioactive alkaloid isolated from Wu-Chu-Yu, has been shown to interact with a wide variety of proteins and modify their expression and activities. In this study, we investigated the interaction between evodiamine and the aryl hydrocarbon receptor (AhR). Molecular modeling results revealed that evodiamine directly interacted with the AhR. Cytosolic receptor binding assay also provided the evidence that evodiamine could interact with the AhR with the K i value of 28.4 ± 4.9 nM. In addition, we observed that evodiamine suppressed the 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induced nuclear translocation of the AhR and the expression of CYP1A1 dose-dependently. These results suggested that evodiamine was able to bind to the AhR as ligand and exhibit antagonistic effects.

  6. Does protein binding modulate the effect of angiotensin II receptor antagonists?

    Directory of Open Access Journals (Sweden)

    Marc P Maillard

    2001-03-01

    Full Text Available IntroductionAngiotensin II AT 1-receptor antagonists are highly bound to plasma proteins (≥ 99%. With some antagonists, such as DuP-532, the protein binding was such that no efficacy of the drug could be demonstrated clinically. Whether protein binding interferes with the efficacy of other antagonists is not known. We have therefore investigated in vitro how plasma proteins may affect the antagonistic effect of different AT1-receptor antagonists.MethodsA radio-receptor binding assay was used to analyse the interaction between proteins and the ability of various angiotensin II (Ang II antagonists to block AT1-receptors. In addition, the Biacore technology, a new technique which enables the real-time monitoring of binding events between two molecules, was used to evaluate the dissociation rate constants of five AT1-receptor antagonists from human serum albumin.ResultsThe in vitro AT 1-antagonistic effects of different Ang II receptor antagonists were differentially affected by the presence of human plasma, with rightward shifts of the IC50 ranging from one to several orders of magnitude. The importance of the shift correlates with the dissociation rate constants of these drugs from albumin. Our experiments also show that the way that AT1-receptor antagonists bind to proteins differs from one compound to another. These results suggest that the interaction with plasma proteins appears to modulate the efficacy of some Ang II antagonists.ConclusionAlthough the high binding level of Ang II receptor antagonist to plasma proteins appears to be a feature common to this class of compounds, the kinetics and characteristics of this binding is of great importance. With some antagonists, protein binding interferes markedly with their efficacy to block AT1-receptors.

  7. In vitro comparison of renal handling and uptake of two somatostatin receptor-specific peptides labeled with indium-111

    International Nuclear Information System (INIS)

    Trejtnar, F.; Novy, Z.; Petrik, M.; Laznickova, A.; Melicharova, L.; Vankova, M.; Laznicek, M.

    2008-01-01

    Radiolabeled receptor-specific somatostatin analogs labeled with gamma- or beta-emitting radionuclides are useful for scintigraphic imaging and/or therapy of selected neuroendocrine tumors. However, significant renal uptake may result in radiotoxicological injury of the kidney and can limit clinical application of the agents. The aim of the study was to analyze renal handling, rate, and mechanism of renal accumulation of two somatostatin receptor-targeted peptides, [DOTA 0 , Tyr 3 , Thr 8 ]-octreotide (DOTA-TATE) and [DOTA 0 , 1-Nal 3 ]-octreotide (DOTA-NOC), labeled with indium-111 using in vitro methods. The perfused rat kidney and freshly isolated rat renal cells were used as experimental models. The perfusion was performed in a recirculation regimen at constant pressure with solution containing bovine albumin, erythrocytes, and a mixture of essential substrates. The renal cells were isolated from rat kidneys using two-phase collagenase perfusion. Accumulation studies were used to evaluate the renal uptake of the peptides and to compare their accumulation with that of passively or actively transported model drugs. The influence of selected inhibitors of receptor-mediated endocytosis and the inhibition of energy-dependent transport processes on the uptake were also investigated using isolated renal cells. The renal clearance of 111 In-DOTA-NOC in the perfused rat kidney was significantly lower than that of 111 In-DOTA-TATE. Reverse situation was found in the case of renal retention. Pretreatment of the perfused kidney with maleate markedly decreased the renal retention. 111 In-DOTA-NOC was accumulated in the isolated renal cells at a higher rate than 111 In-DOTA-TATE (ratio 3:1). The uptake of the radiopeptides in renal cells was higher than the uptake of not only the passively transported sucrose but also actively transported and accumulated methylglucose. The rank order of potency to inhibit the uptake by active endocytosis was approximately aprotinin

  8. Purification and reconstitution of the calcium antagonist receptor of the voltage-sensitive calcium channel

    International Nuclear Information System (INIS)

    Curtis, B.M.

    1986-01-01

    Treatment with digitonin solubilized the calcium antagonist receptor as a stable complex with [ 3 H]nitrendipine from rat brain membranes. The solubilized complex retains allosteric coupling to binding sites for diltiazem, verapamil, and inorganic calcium antagonist sites. The calcium antagonist receptor from cardiac sarcolemma and the transverse-tubule membrane of skeletal muscle is also efficiently solubilized with digitonin and the receptor in all three tissues is a large glycoprotein with a sedimentation coefficient of 20 S. The T-tubule calcium antagonist receptor complex was extensively purified by a combination of chromatography on WGA-Sepharose, ion exchange chromatography, and sedimentation on sucrose gradients to yield preparations estimated to be 41% homogeneous by specific activity and 63% homogeneous by SDS gel electrophoresis. Analysis of SDS gels detect three polypeptides termed α(Mr 135,000), β(Mr 50,000), and γ(Mr 32,000) as noncovalently associated subunits of the calcium antagonist receptor. The α and γ subunits are glycosylated polypeptides, and the molecular weight of the core polypeptides are 108,000 and 24,000 respectively. The calcium antagonist receptor was reconstituted into a phospholipid bilayer by adding CHAPS and exogeneous lipid to the purified receptor followed by rapid detergent removal. This procedure resulted in the incorporation of 45% of the calcium antagonist receptor into closed phospholipid vesicles. Data suggests that the α, β, and γ subunits of the T-tubule calcium antagonist receptor are sufficient to form a functional calcium channel

  9. Anti-HIV Effect of Liposomes Bearing CXCR4 Receptor Antagonist ...

    African Journals Online (AJOL)

    Keywords: Antagonist, CXCR4, Liposomes, Receptor, Inflammation, HIV. Tropical Journal of ... receptors and inhibits HIV-1 entry mediated through CCR3, CCR5, and ..... circulation, facilitating HIV-targeted drug delivery. By tissue distribution ...

  10. Orexin receptor antagonists as therapeutic agents for insomnia

    Directory of Open Access Journals (Sweden)

    Ana Clementina Equihua

    2013-12-01

    Full Text Available Insomnia is a common clinical condition characterized by difficulty initiating or maintaining sleep, or non-restorative sleep with impairment of daytime functioning.Currently, treatment for insomnia involves a combination of cognitive behavioral therapy and pharmacological therapy. Among pharmacological interventions, the most evidence exists for benzodiazepine receptor agonist drugs (GABAA receptor, although concerns persist regarding their safety and their limited efficacy. The use of these hypnotic medications must be carefully monitored for adverse effects.Orexin (hypocretin neuropeptides have been shown to regulate transitions between wakefulness and sleep by promoting cholinergic/monoaminergic neural pathways. This has led to the development of a new class of pharmacological agents that antagonize the physiological effects of orexin. The development of these agents may lead to novel therapies for insomnia without the side effect profile of hypnotics (e.g. impaired cognition, disturbed arousal, and motor balance difficulties. However, antagonizing a system that regulates the sleep-wake cycle may create an entirely different side effect profile. In this review, we discuss the role of orexin and its receptors on the sleep-wake cycle and that of orexin antagonists in the treatment of insomnia.

  11. Bovine pancreatic polypeptide as an antagonist of muscarinic cholinergic receptors

    International Nuclear Information System (INIS)

    Pan, G.Z.; Lu, L.; Qian, J.; Xue, B.G.

    1987-01-01

    In dispersed acini from rat pancreas, it was found that bovine pancreatic polypeptide (BPP) and its C-fragment hexapeptide amide (PP-6), at concentrations of 0.1 and 30 μM, respectively, could significantly inhibit amylase secretion stimulated by carbachol, and this inhibition by BPP was dose dependent. 45 Ca outflux induced by carbachol was also inhibited by BPP or PP-6, but they had no effect on cholecystokinin octapeptide- (CCK-8) or A23187-stimulated 45 Ca outflux. BPP was also capable of displacing the specific binding of [ 3 H]-quinuclidinyl benzilate to its receptors, and it possessed a higher affinity (K/sub i/35nM) than carbachol (K/sub i/ 1.8 μM) in binding with M-receptors. It is concluded from this study that BPP acts as an antagonist of muscarinic cholinergic receptors in rat pancreatic acini. In addition, BPP inhibited the potentiation of amylase secretion caused by the combination of carbachol plus secretin or vasoactive intestinal peptide. This may be a possible explanation of the inhibitory effect of BPP on secretin-induced pancreatic enzyme secretion shown in vivo, since pancreatic enzyme secretion stimulated by secretin under experimental conditions may be the result of potentiation of enzyme release produced by the peptide in combination with a cholinergic stimulant

  12. NMDA receptor antagonist ketamine impairs feature integration in visual perception.

    Science.gov (United States)

    Meuwese, Julia D I; van Loon, Anouk M; Scholte, H Steven; Lirk, Philipp B; Vulink, Nienke C C; Hollmann, Markus W; Lamme, Victor A F

    2013-01-01

    Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans.

  13. NMDA receptor antagonist ketamine impairs feature integration in visual perception.

    Directory of Open Access Journals (Sweden)

    Julia D I Meuwese

    Full Text Available Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA receptors in monkeys can abolish neural signals related to figure-ground segregation and feature integration. However, it is unknown whether this also affects perceptual integration itself. Therefore, we tested whether ketamine, a non-competitive NMDA receptor antagonist, reduces feature integration in humans. We administered a subanesthetic dose of ketamine to healthy subjects who performed a texture discrimination task in a placebo-controlled double blind within-subject design. We found that ketamine significantly impaired performance on the texture discrimination task compared to the placebo condition, while performance on a control fixation task was much less impaired. This effect is not merely due to task difficulty or a difference in sedation levels. We are the first to show a behavioral effect on feature integration by manipulating the NMDA receptor in humans.

  14. Somatostatin Receptor SPECT/CT using 99mTc Labeled HYNIC-TOC Aids in Diagnosis of Primary Optic Nerve Sheath Meningioma.

    Science.gov (United States)

    Chandra, Piyush; Purandare, Nilendu; Shah, Sneha; Agrawal, Archi; Rangarajan, Venkatesh

    2017-01-01

    Primary optic nerve sheath meningiomas (ONSM) are rare, benign and slow growing tumor involving the intra-orbital/intra-canalicular segment of the optic nerve. Untreated, they can potentially lead to visual deterioration. Magnetic resonance (MR) is the gold standard imaging modality for diagnosing the entity. Often, a clinical dilemma exists to narrow the differential diagnosis of an enhancing intra-orbital mass on MR. Molecular imaging provides a high degree of precision in diagnosing meningioma in view of relatively high levels of somatostatin receptor expression by these tumors. The following case demonstrates the potential clinical utility of somatostatin receptor SPECT using 99m Tc- labeled HYNIC-TOC in clinical diagnosis of ONSM.

  15. PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

    International Nuclear Information System (INIS)

    Hofmann, M.; Gazdhar, A.; Weitzel, T.; Schmid, R.; Krause, T.

    2006-01-01

    Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and humans

  16. PET/CT imaging of human somatostatin receptor 2 (hsstr2) as reporter gene for gene therapy

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, M. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)]. E-mail: Michael.Hofmann@insel.ch; Gazdhar, A. [Division of Pulmonary Medicine, University Hospital Bern (Switzerland); Weitzel, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland); Schmid, R. [Division of Thoracic Surgery, University Hospital Bern (Switzerland); Krause, T. [Molecular Imaging and Therapy Group (MIT-Bern), Clinic of Nuclear Medicine, Inselspital, Medical School Bern (Switzerland)

    2006-12-20

    Localized information on region-selective gene expression in small animals is widely obtained by use of reporter genes inducing light emission. Using these reporter genes for imaging deep inside the human body fluorescent probes are hindered by attenuation, scattering and possible fluorescence quenching. This can be overcome by use of radio-peptide receptors as reporter genes. Therefore, the feasibility of the somatostatin receptor 2 expression vector system for expression imaging was checked against a control vector containing luciferase gene. For in vivo transduction of vector DNA into the rat forelimb muscles the in vivo electroporation technique was chosen because of its high regio-selectivity. The gene expression was imaged by high-sensitive CCD camera (luciferase activity) and by PET/CT using a Ga-68-DOTATOC as radio peptide probe. The relative sstr2 expression was enhanced by gene transduction at maximum to a factor of 15. The PET/CT images could be fully quantified. The above demonstrated feasibility of radio-peptide PET/CT reporter gene imaging may serve in the future as a tool for full quantitative understanding of regional gene expression, especially in large animals and human000.

  17. Molecular imaging with {sup 68}Ga-SSTR PET/CT and correlation to immunohistochemistry of somatostatin receptors in neuroendocrine tumours

    Energy Technology Data Exchange (ETDEWEB)

    Kaemmerer, Daniel; Haugvik, Sven-Petter; Hommann, Merten [Zentralklinik Bad Berka GmbH, Department of General and Visceral Surgery, Bad Berka (Germany); Peter, Luisa; Lupp, Amelie; Schulz, Stefan [University of Jena, Department of Pharmacology and Toxicology, Jena (Germany); Saenger, Joerg [Laboratory of Pathology and Cytology, Bad Berka (Germany); Prasad, Vikas; Kulkarni, Harshad; Baum, Richard Paul [Zentralklinik Bad Berka, Department of Nuclear Medicine and Center for PET, Bad Berka (Germany)

    2011-09-15

    Somatostatin receptors (SSTR) are known for an overexpression in gastroenteropancreatic neuroendocrine tumours (GEP-NET). The aim of the present study was to find out if the receptor density predicted by the semi-quantitative parameters generated from the static positron emission tomography (PET/CT) correlated with the in vitro immunohistochemistry using a novel rabbit monoclonal anti-SSTR2A antibody (clone UMB-1) for specific SSTR2A immunohistochemistry and polyclonal antibodies for SSTR1 and 3-5. Overall 14 surgical specimens generated from 34 histologically documented GEP-NET patients were correlated with the preoperative {sup 68}Ga-DOTA-NOC PET/CT. Quantitative assessment of the receptor density was done using the immunoreactive score (IRS) of Remmele and Stegner; the additional 4-point IRS classification for immunohistochemistry and standardized uptake values (SUV{sub max} and SUV{sub mean}) were used for PET/CT. The IRS for SSTR2A and SSTR5 correlated highly significant with the SUV{sub max} on the PET/CT (p < 0.001; p < 0.05) and the IRS for SSTR2A with the SUV{sub mean} (p < 0.013). The level of SSTR2A score correlated significantly with chromogranin A staining and indirectly to the tumour grading. The highly significant correlation between SSTR2A and SSTR5 and the SUV{sub max} on the {sup 68}Ga-DOTA-NOC PET/CT scans is concordant with the affinity profile of {sup 68}Ga-DOTA-NOC to the SSTR subtypes and demonstrates the excellent qualification of somatostatin analogues in the diagnostics of NET. This study correlating somatostatin receptor imaging using {sup 68}Ga-DOTA-NOC PET/CT with immunohistochemically analysed SSTR also underlines the approval of therapy using somatostatin analogues, follow-up imaging as well as radionuclide therapy. (orig.)

  18. 99Tcm labelling and in vitro binding of dextran-somatostatin conjugate

    International Nuclear Information System (INIS)

    Cui Haiping; China Inst. of Atomic Energy, Beijing; Zhai Shizhen; Du Jin; Beijing Univ., Beijing

    2006-01-01

    Natural somatostatin and dextran-20 are used to synthesis somatostatin-dextran (SMS-Dx 20 ). The in vitro somatostatin receptor competition binding study of somatostatin-dextran is carried out by using rate brain cortex membranes (express somatostatin receptor type 2) and 125 I-Tyr 3 -Octreotide as a radioligand. The somatostatin-dextran conjugate is then labelled with 99 Tc m using SnCl 2 as reduce agent and tested for its in vitro binding properties. The somatostatin-dextran conjugate shows high somatostatin receptor binding affinity, i.e. in the same IC 50 value as the reference ligand Octreotide (IC 50 ∼5.95 nmol/L). The labelling efficiency is more than 85%. The specific binding of 99 Tc m labeled somatostatin-dextran conjugate is 25%-40%. The somatostatin-dextran conjugate is worthy of further investigation for 99 Tc m radiolabeling with diagnostic possibilities for somatostatin receptor positive tumors. (authors)

  19. Effects of a novel bradykinin B1 receptor antagonist and angiotensin II receptor blockade on experimental myocardial infarction in rats.

    Directory of Open Access Journals (Sweden)

    Dongmei Wu

    Full Text Available The aim of the present study was to evaluate the cardiovascular effects of the novel bradykinin B1 receptor antagonist BI-113823 following myocardial infarction (MI and to determine whether B1 receptor blockade alters the cardiovascular effects of an angiotensin II type 1 (AT1 receptor antagonist after MI in rats.Sprague Dawley rats were subjected to permanent occlusion of the left descending coronary artery. Cardiovascular function was determined at 7 days post MI. Treatment with either B1 receptor antagonist (BI-113823 or AT1 receptor antagonist (irbesartan alone or in combination improved post-MI cardiac function as evidenced by attenuation of elevated left ventricular end diastolic pressure (LVEDP; greater first derivative of left ventricular pressure (± dp/dt max, left ventricle ejection fraction, fractional shorting, and better wall motion; as we as reductions in post-MI up-regulation of matrix metalloproteinases 2 (MMP-2 and collagen III. In addition, the cardiac up-regulation of B1 receptor and AT1 receptor mRNA were markedly reduced in animals treated with BI 113823, although bradykinin B2 receptor and angiotensin 1 converting enzyme (ACE1 mRNA expression were not significantly affected by B1 receptor blockade.The present study demonstrates that treatment with the novel B1 receptor antagonist, BI-113823 improves post-MI cardiac function and does not influence the cardiovascular effects of AT1 receptor antagonist following MI.

  20. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    Energy Technology Data Exchange (ETDEWEB)

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-03-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor.

  1. Inhibition of radiation-induced polyuria by histamine receptor antagonists

    International Nuclear Information System (INIS)

    Donlon, M.A.; Melia, J.A.; Helgeson, E.A.; Wolfe, W.W.

    1986-01-01

    In previous studies the authors have demonstrated that gamma radiation results in polyuria, which is preceded by polydypsia. This suggests that the increased thirst elicited by radiation causes increased urinary volume (UV). Histamine, which is released following radiation exposure, also elicits drinking by nonirradiated rats when administered exogenously. In this study the authors have investigated both the role of water deprivation and the effect of histamine receptor antagonists (HRA) on radiation-induced polyuria. Sprague-Dawley rats were housed individually in metabolic cages. Water was allowed ad libitum except in deprivation experiments where water was removed for 24 hr immediately following radiation. Cimetidine (CIM), an H2 HRA, and dexbromopheniramine (DXB), an H1 HRA, were administered i.p. (16 and 1 mg/kg, respectively) 30 min prior to irradiation (950 rads from a cobalt source). UV was determined at 24-hr intervals for 3 days preceding irradiation and 24 hr postirradiation. UV in DXB treated rats was significantly reduced 24 hr postirradiation (CON = 427 +/- 54%; DXB = 247 +/- 39% of preirradiated CON) compared to postirradiation control values. CIM did not affect postirradiation UV. These data suggest that radiation-induced polyuria is caused by polydypsia which is, in part, mediated by histamine induced by an H1 receptor

  2. Return of D4 Dopamine Receptor Antagonists in Drug Discovery.

    Science.gov (United States)

    Lindsley, Craig W; Hopkins, Corey R

    2017-09-14

    The dopamine D 4 receptor garnered a great deal of interest in the early 1990s when studies showed the atypical antipsychotic clozapine possessed higher affinity for D 4 , relative to other dopamine receptor subtypes, and that this activity might underlie the unique clinical efficacy of clozapine. Unfortunately, D 4 antagonists that were developed for schizophrenia failed in the clinic. Thus, D 4 fell out of favor as a therapeutic target, and work in this area was silent for decades. Recently, D 4 ligands with improved selectivity for D 4 against not only D 1-3,5 but also other biogenic amine targets have emerged, and D 4 is once again in the spotlight as a novel target for both addiction and Parkinson's disease (PD), as well as other emerging diseases. This report will review the historical data for D 4 , review the known D 4 ligands, and then highlight new data supporting a role for D 4 inhibition in addiction, PD, and cancer.

  3. Preparation and biological evaluation of [(99m)Tc/EDDA/Tricine/HYNIC(0), BzThi(3)]-octreotide for somatostatin receptor-positive tumor imaging.

    Science.gov (United States)

    Erfani, Mostafa; Shafiei, Mohammad; Mazidi, Mohammad; Goudarzi, Mostafa

    2013-04-01

    Somatostatin-derived analogues play an important role in the diagnosis and treatment of neuroendocrine tumors. The aim of this study was to evaluate a new somatostatin analogue designed for labeling with (99m)Tc: [6-hydrazinopyridine-3-carboxylic acid (HYNIC(0)), β-(3-benzothienyl)-Ala (BzThi(3))]-octreotide ([HYNIC]-BOC), using ethylenediamine-N,N'-diacetic acid (EDDA) and tricine as coligands. Synthesis was performed on a solid phase using a standard Fmoc strategy. The HYNIC-peptide conjugate was radiolabeled with (99m)Tc and characterized by ITLC and high-performance liquid chromatography (HPLC). In vitro studies were carried out in sstr2 expressing AR4-2J cell lines. In vivo distribution studies were performed in rats bearing the AR4-2J tumor. The radiolabeled complex could be prepared at high-specific activities and >95% radiochemical yield as determined by HPLC. The peptide conjugate showed high-affinity binding for sstr2. The radioligand showed high and specific internalization into AR4-2J cells (18.19%±0.21% at 4 hours). In vivo distribution studies in rats bearing tumor have shown a receptor-specific uptake of radioactivity in somatostatin receptor-positive organs. After 4 hours, uptake in the AR4-2J tumor was 1.71%±0.36% injected dose per gram tissue (%ID/g). These data show that [(99m)Tc/EDDA/Tricine/HYNIC(0), BzThi(3)]-octreotide is a specific radioligand for the somatostatin receptor-positive tumors and is a suitable candidate for clinical studies.

  4. Structural determinants for antagonist pharmacology that distinguish the rho1 GABAC receptor from GABAA receptors.

    Science.gov (United States)

    Zhang, Jianliang; Xue, Fenqin; Chang, Yongchang

    2008-10-01

    GABA receptor (GABAR) types C (GABACR) and A (GABAAR) are both GABA-gated chloride channels that are distinguished by their distinct competitive antagonist properties. The structural mechanism underlying these distinct properties is not well understood. In this study, using previously identified binding residues as a guide, we made individual or combined mutations of nine binding residues in the rho1 GABACR subunit to their counterparts in the alpha1beta2gamma2 GABAAR or reverse mutations in alpha1 or beta2 subunits. The mutants were expressed in Xenopus laevis oocytes and tested for sensitivities of GABA-induced currents to the GABAA and GABAC receptor antagonists. The results revealed that bicuculline insensitivity of the rho1 GABACR was mainly determined by Tyr106, Phe138 and Phe240 residues. Gabazine insensitivity of the rho1 GABACR was highly dependent on Tyr102, Tyr106, and Phe138. The sensitivity of the rho1 GABACR to 3-aminopropyl-phosphonic acid and its analog 3-aminopropyl-(methyl)phosphinic acid mainly depended on residues Tyr102, Val140, FYS240-242, and Phe138. Thus, the residues Tyr102, Tyr106, Phe138, and Phe240 in the rho1 GABACR are major determinants for its antagonist properties distinct from those in the GABAAR. In addition, Val140 in the GABACR contributes to 3-APA binding. In conclusion, we have identified the key structural elements underlying distinct antagonist properties for the GABACR. The mechanistic insights were further extended and discussed in the context of antagonists docking to the homology models of GABAA or GABAC receptors.

  5. Anticonvulsant effects of isomeric nonimidazole histamine H3 receptor antagonists

    Directory of Open Access Journals (Sweden)

    Sadek B

    2016-11-01

    , in which 3-piperidinopropan-1-ol in ligand 2 was replaced by (4-(3-(piperidin-1-ylpropoxyphenylmethanol, and its (S-enantiomer (4 significantly and in a dose-dependent manner reduced convulsions or exhibited full protection in MES and PTZ convulsions model, respectively. Interestingly, the protective effects observed for the (R-enantiomer (3 in MES model were significantly greater than those of the standard H3R inverse agonist/antagonist pitolisant, comparable with those observed for PHT, and reversed when rats were pretreated with the selective H3R agonist R-(α-methyl-histamine. Comparisons of the observed antagonistic in vitro affinities among the ligands 1–6 revealed profound stereoselectivity at human H3Rs with varying preferences for this receptor subtype. Moreover, the in vivo anticonvulsant effects observed in this study for ligands 1–6 showed stereoselectivity in different convulsion models in male adult rats. Keywords: histamine, H3 receptor, isomeric antagonists, anticonvulsant activity, stereo­selectivity

  6. Single photon emission computed tomography procedure improves accuracy of somatostatin receptor scintigraphy in endocrine gastro-entero-pancreatic tumours

    International Nuclear Information System (INIS)

    Lebtahi, R.; Genin, R.; Rouzet, F.; Bleicner-Perez, S.; Lievre, A.; Scigliano, S.; Vialle, C.; Le Guludec, D.; Cadiot, G.; Sobhani, I.; Mignon, M.

    2005-01-01

    Somatostatin receptors scintigraphy (SRS) is a sensitive method for the detection of endocrine gastro-entero-pancreatic tumors. The aim of this study was to evaluate the sensitivity of anterior and posterior planar associated to single photon emission computerized tomography (SPECT) compared to anterior and posterior planar associated to additional lateral and oblique views in the detection of abdominal endocrine tumors. One hundred and sixty four patients with endocrine gastro-entero-pancreatic tumors were included in this study. Scintigraphic images were performed after injection of 189 ± 23 MBq of 111 In-Pentetreotide. Abdominal planar images were performed 4 h and 24 hours after injection. Abdominal SPECT was performed at 24 hours. The combination of anterior and posterior abdominal planar images with SPECT using iterative reconstruction detected significantly more tumoral sites compared to multiple planar images (298 versus 280 for the liver, p = 0.01 and 90 versus 88 for coeliac area). In particular liver lesions were better delineated on tomographic slices. The combination of 111 In-Pentetreotide SPECT with anterior and posterior planar images is more sensitive than multiple planar images to detect abdominal endocrine tumors. (author)

  7. “In-house” preparation of 99mTc-EDDA/HYNIC-TOC, a specific targeting agent for somatostatin receptor scintigraphy

    Directory of Open Access Journals (Sweden)

    Sonja Kuzmanovska

    2012-01-01

    Full Text Available The use of radiolabeled peptide ligands as diagnostics and therapeutics in nuclear oncology has increased recently. One of the most frequently used radiopharmaceutical is 99mTc-EDDA/HYNIC-TOC, a somatostatin analog with affinity for certain types of somatostatin receptors, overexpressed in tumors of neuroendocrine origin. The radiopharmaceutical is not readily available; therefore we introduced its “in house” preparation within project activities supported by the International Atomic Energy Agency (IAEA. We optimized the radiolabeling protocol, prepared a small batch of frozen kits, performed ITLC quality control and animal biodistribution during the preclinical evaluation procedures. The co-ligand exchange labeling procedure was carried out at 100°C during 10 min, resulting in radiochemical purity >90%. The biodistribution scintigrams in normal Wistar rats showed rapid blood clearance after 15 min and predominant kidney accumulation after 4 h, in accordance with the data reported by other authors. Storage stability of the formulated small batch frozen kit (-20°C was evaluated within 6 months, with radiolabeling yield ranging between 94,3% and 96,9%. We conclude that frozen kit can be a safe alternative to the freeze-dried for small batch in house production, and after the satisfactory preclinical evaluation, the “in house” prepared 99mTc-EDDA/ HYNIC-TOC can be introduced in clinical practice as specific targeting agent for somatostatin receptor scintigraphy.

  8. Positron emission tomography study on pancreatic somatostatin receptors in normal and diabetic rats with 68Ga-DOTA-octreotide: a potential PET tracer for beta cell mass measurement.

    Science.gov (United States)

    Sako, Takeo; Hasegawa, Koki; Nishimura, Mie; Kanayama, Yousuke; Wada, Yasuhiro; Hayashinaka, Emi; Cui, Yilong; Kataoka, Yosky; Senda, Michio; Watanabe, Yasuyoshi

    2013-12-06

    Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, and the loss or dysfunction of pancreatic beta cells has been reported before the appearance of clinical symptoms and hyperglycemia. To evaluate beta cell mass (BCM) for improving the detection and treatment of DM at earlier stages, we focused on somatostatin receptors that are highly expressed in the pancreatic beta cells, and developed a positron emission tomography (PET) probe derived from octreotide, a metabolically stable somatostatin analog. Octreotide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), a chelating agent, and labeled with (68)Gallium ((68)Ga). After intravenous injection of (68)Ga-DOTA-octreotide, a 90-min emission scan of the abdomen was performed in normal and DM model rats. The PET studies showed that (68)Ga-DOTA-octreotide radioactivity was highly accumulated in the pancreas of normal rats and that the pancreatic accumulation was significantly reduced in the rats administered with an excess amount of unlabeled octreotide or after treatment with streptozotocin, which was used for the chemical induction of DM in rats. These results were in good agreement with the ex vivo biodistribution data. These results indicated that the pancreatic accumulation of (68)Ga-DOTA-octreotide represented specific binding to the somatostatin receptors and reflected BCM. Therefore, PET imaging with (68)Ga-DOTA-octreotide could be a potential tool for evaluating BCM. Copyright © 2013 Elsevier Inc. All rights reserved.

  9. Iontophoresis of endothelin receptor antagonists in rats and men.

    Directory of Open Access Journals (Sweden)

    Matthieu Roustit

    Full Text Available The treatment of scleroderma-related digital ulcers is challenging. The oral endothelin receptor antagonist (ERA bosentan has been approved but it may induce liver toxicity. The objective of this study was to test whether ERAs bosentan and sitaxentan could be locally delivered using iontophoresis.Cathodal and anodal iontophoresis of bosentan and sitaxentan were performed on anaesthetized rat hindquarters without and during endothelin-1 infusion. Skin blood flow was quantified using laser-Doppler imaging and cutaneous tolerability was assessed. Iontophoresis of sitaxentan (20 min, 20 or 100 µA was subsequently performed on the forearm skin of healthy men (n = 5.In rats neither bosentan nor sitaxentan increased skin blood flux compared to NaCl. When simultaneously infusing endothelin-1, cathodal iontophoresis of sitaxentan increased skin blood flux compared to NaCl (AUC(0-20 were 44032.2 ± 12277 and 14957.5 ± 23818.8 %BL.s, respectively; P = 0.01. In humans, sitaxentan did not significantly increase skin blood flux as compared to NaCl. Iontophoresis of ERAs was well tolerated both in animals and humans.This study shows that cathodal iontophoresis of sitaxentan but not bosentan partially reverses endothelin-induced skin vasoconstriction in rats, suggesting that sitaxentan diffuses into the dermis. However, sitaxentan does not influence basal skin microvascular tone in rats or in humans.

  10. Side Effects of Leukotriene Receptor Antagonists in Asthmatic Children.

    Science.gov (United States)

    Erdem, Semiha Bahceci; Nacaroglu, Hikmet Tekin; Unsal Karkiner, Canan Sule; Gunay, Ilker; Can, Demet

    2015-10-01

    Leukotriene receptor antagonists (LTRAs) are drugs which have been widely used more than ten years. As the use of LTRAs increases, our knowledge with respect to their side effects increases as well. The objective of our study was to evaluat the observed side effects of LTRAs used in patients with astma. 1024 patients treated only with LTRAs owing to asthma or early wheezing were included in the study for a five-year period. The observed side effects of LTRAs in these patients were retrospectively investigated. The side effects were divided into two parts as psychiatric and non-psychiatric. Among the 1024 cases included in the study, 67.5% of the patients out of 41 with side effects were male, 32.5% were female and the average age was 6.5 years. The rate of patients with asthma was 63.41% and 36.58% of the patients had early wheezing. It was determined that sex, age and diagnosis (early wheezing or asthma) of the patients were ineffective in the emergence of side effects. The average period for the emergence of side effects was the first month. It was observed that hyperactivity was the most frequently observed psychiatric side effect and that abdominal pain was the non-psychiatric side effect. The side effects of LTRAs were common in children. Therefore, patients must be informed at the beginning of the treatment and they must be evaluated at certain intervals.

  11. Preliminary clinical evaluation of Somatostatin Receptor Scintigraphy (SRS) with 99mTc-EDDA/HYNIC-TATE in comparison to 111In-Octreoscan and 131 I MIBG scans

    International Nuclear Information System (INIS)

    Hubalewska, A.; Fross, K.; Staszczak, A.; Huszno, B.; Mikolajczak, R.; Gorska, A.

    2004-01-01

    Full text: Over expression of somatostatin receptors in various neuroendocrine tumours prompted development of somatostatin analogues, which after radioactive labelling, could be used in oncological diagnostics. Somatostatin Receptor Positive Tumour (Spt) imaging with 111In-DTPA-DPhe1- octreotide (111In-Octreoscan) has become a widely used diagnostic procedure in clinical nuclear medicine. However 111In as a radiolabel has several drawbacks, including limited availability, sub optimal gamma energy and high radiation burden to the patient. Technetium (99mTc) labelling of somatostatin analogues is especially attractive due to the ready availability of 99mTc from generators and its well recognised favourable imaging characteristics. HYNIC conjugated Tyr 3 -Octreotate (HYNIC-TATE) prepared in our laboratory in a dry kit form was labelled with technetium-99mTc, with tricine and EDDA used as coligands. Tyr3-octreotate differs from octreotide (OC) by more hydrophilic tyrosine in the third position and the terminal threonine, which replaced threoninol present in OC. In vitro studies using cell lines transfected with somatostatin receptors (SSTR) revealed that octreotate shows 14- 17 times better binding affinity for SSTR type 2 than does OC. It is expected to clear more rapidly from non-target tissues as a result of the carboxylic group at the C-terminal of the peptide. HYNIC has been used as bifunctional chelator in 99mTc-HYNIC-Tyr3-octreotide (TOC) by Maecke and Behe, who reported on its favourable preclinical characteristics when EDDA was used as a co-ligand. These pre-clinical data were confirmed by Decristoforo and Mather and their early clinical studies appeared recently. The new radiopharmaceutical - 99mTc-DDA/HYNICTATE was evaluated in-vitro and in-vivo in an animal model and its potential for SSTR scintigraphy was documented. In the current patient study the diagnostic usefulness of the new radiopharmaceutical was tested for detection of tumours expressing SSTR

  12. Scintigraphy with labelled analogues of the somatostatin

    International Nuclear Information System (INIS)

    Duet, M.; Ajzenberg, C.; Warnet, A.; Mundler, O.

    1998-01-01

    The receptors of the somatostatin have been localized in a big number of tumors, whom a great number are neuro-endocrine tumors. However, some tumors that have not this differentiation (breast cancer, lymphomas, cerebral tumors) possess them as well. Analogues of somatostatin, labelled with isotopes having a gamma emission, allow from now their detection in vivo. (N.C.)

  13. Anti-idiotypic antibody: A new strategy for the development of a growth hormone receptor antagonist.

    Science.gov (United States)

    Lan, Hainan; Zheng, Xin; Khan, Muhammad Akram; Li, Steven

    2015-11-01

    In general, traditional growth hormone receptor antagonist can be divided into two major classes: growth hormone (GH) analogues and anti-growth hormone receptor (GHR) antibodies. Herein, we tried to explore a new class of growth hormone receptor (GHR) antagonist that may have potential advantages over the traditional antagonists. For this, we developed a monoclonal anti-idiotypic antibody growth hormone, termed CG-86. A series of experiments were conducted to characterize and evaluate this antibody, and the results from a competitive receptor-binding assay, Enzyme Linked Immunosorbent Assays (ELISA) and epitope mapping demonstrate that CG-86 behaved as a typical Ab2β. Next, we examined its antagonistic activity using in vitro cell models, and the results showed that CG-86 could effectively inhibit growth hormone receptor-mediated signalling and effectively inhibit growth hormone-induced Ba/F3-GHR638 proliferation. In summary, these studies show that an anti-idiotypic antibody (CG-86) has promise as a novel growth hormone receptor antagonist. Furthermore, the current findings also suggest that anti-idiotypic antibody may represent a novel strategy to produce a new class of growth hormone receptor antagonist, and this strategy may be applied with other cytokines or growth factors. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Enhanced bilateral somatostatin receptor expression in mediastinal lymph nodes (''chimney sign'') in occult metastatic medullary thyroid cancer: a typical site of tumour manifestation?

    International Nuclear Information System (INIS)

    Behr, T.M.; Gratz, S.; Markus, P.M.; Dunn, R.M.; Huefner, M.; Becker, H.; Becker, W.

    1997-01-01

    In medullary thyroid cancer (MTC), post-surgically elevated plasma calcitonin and/or carcinoembryonic antigen levels frequently indicate persisting metastatic disease, although conventional diagnostic procedures fail to localize the responsible lesions (occult disease). Somatostatin analogues have been used successfully in disease localization, but recently concerns have been raised that increased thoracic uptake of indium-111 pentetreotide in patients with previous external beam irradiation may represent a false-positive finding, caused by post-irradiation pulmonary fibrosis. We recently examined seven patients with metastatic MTC by somatostatin receptor scintigraphy (six with occult and one with established disease). In four patients, all of whom had stable or slowly rising tumour marker levels over several years, a chimney-like bilateral mediastinal uptake of indium-111 pentetreotide was found. In two patients with persisting hypercalcitonaemia immediately after primary surgery, supraclavicular lymph node metastases were identified as the responsible lesions. None of these seven patients had prior external beam radiation therapy. In two cases, histological confirmation was obtained. In one patient, disease progression could be shown during follow-up. These data suggest that bilateral mediastinal lymph node involvement is a typical site of disease in slowly progressing occult metastatic MTC; the ''chimney sign'' may represent a typical finding with somatostatin analogues in such cases. Therefore, we believe that even in the case of prior external beam irradiation, mediastinal uptake of octreotide might represent metastatic MTC rather than radiation fibrosis. (orig.). With 2 figs., 1 tab

  15. Melanin concentrating hormone receptor 1 (MCHR1) antagonists - Still a viable approach for obesity treatment?

    DEFF Research Database (Denmark)

    Högberg, T.; Frimurer, T.M.; Sasmal, P.K.

    2012-01-01

    Obesity is a global epidemic associated with multiple severe diseases. Several pharmacotherapies have been investigated including the melanin concentrating hormone (MCH) and its receptor 1. The development of MCHR1 antagonists are described with a specific perspective on different chemotypes...

  16. Sympatholytic properties of several AT(1)-receptor antagonists in the isolated rabbit thoracic aorta

    NARCIS (Netherlands)

    Nap, Alexander; Balt, Jippe C.; Pfaffendorf, Martin; van Zwieten, Pieter A.

    2002-01-01

    Objective To evaluate the facilitating effect of angiotensin II on sympathetic neurotransmission to quantitatively compare the sympatho-inhibitory potencies of the selective AT(1)-receptor antagonists losartan, irbesartan and telmisartan in the isolated rabbit thoracic aorta. Design To investigate

  17. Muscarinic receptor antagonists for overactive bladder treatment: does one fit all?

    NARCIS (Netherlands)

    Witte, Lambertus P. W.; Mulder, Wilhelmina M. C.; de La Rosette, Jean J. M. C. H.; Michel, Martin C.

    2009-01-01

    Purpose of review To review evidence and regulatory dosing recommendations for muscarinic receptor antagonists used in the treatment of overactive bladder symptom complex (darifenacin, fesoterodine oxybutynin propiverine solifenacin tolterodine trospium) in special patient populations. Recent

  18. Successful treatment of hereditary angioedema with bradykinin B2-receptor antagonist icatibant.

    Science.gov (United States)

    Krause, Karoline; Metz, Martin; Zuberbier, Torsten; Maurer, Marcus; Magerl, Markus

    2010-04-01

    The bradykinin B2 receptor antagonist icatibant has recently become available for treating hereditary angioedema. Our observations demonstrate icatibant to be effective and safe for the treatment of both, abdominal and cutaneous attacks in a practice setting beyond clinical studies.

  19. The clinical impact of a combined gamma camera/CT imaging system on somatostatin receptor imaging of neuroendocrine tumours

    International Nuclear Information System (INIS)

    Hillel, P.G.; Beek, E.J.R. van; Taylor, C.; Lorenz, E.; Bax, N.D.S.; Prakash, V.; Tindale, W.B.

    2006-01-01

    AIM: With a combined gamma camera/CT imaging system, CT images are obtained which are inherently registered to the emission images and can be used for the attenuation correction of SPECT and for mapping the functional information from these nuclear medicine tomograms onto anatomy. The aim of this study was to evaluate the clinical impact of SPECT/CT using such a system for somatostatin receptor imaging (SRI) of neuroendocrine tumours. MATERIALS AND METHODS: SPECT/CT imaging with 111 In-Pentetreotide was performed on 29 consecutive patients, the majority of whom had carcinoid disease. All SPECT images were first reported in isolation and then re-reported with the addition of the CT images for functional anatomical mapping (FAM). RESULTS: Fifteen of the 29 SPECT images were reported as abnormal, and in 11 of these abnormal images (73%) FAM was found to either establish a previously unknown location (7/11) or change the location (4/11) of at least one lesion. The revised location could be independently confirmed in 64% of these cases. Confirmation of location was not possible in the other patients due to either a lack of other relevant investigations, or the fact that lesions seen in the SPECT images were not apparent in the other investigations. FAM affected patient management in 64% of the cases where the additional anatomical information caused a change in the reported location of lesions. CONCLUSION: These results imply that FAM can improve the reporting accuracy for SPECT SRI with significant impact on patient management

  20. Contribution of scintigraphy for somatostatin receptors in case of non-iodine-fixating metastases of thyroid epithelioma

    International Nuclear Information System (INIS)

    Couty, H.; Andrieu, J.M.; Baudet, L.; Faurous, P.; Artus, J.C.; Jaffiol, C.

    1997-01-01

    The objective of this work was to evaluate the sensitivity and importance of scintigraphy of somatostatin receptors (SSR) in the detection of non iodine-fixating metastases of thyroid epithelioma. We have studied retrospectively 7 patients with a detectable thyroglobulin under hormonal hindrance, amounting after cessation of treatment up to 72 - 1500 μ g/l and a normal post-irradiation therapy (3.7 GBq of 131 I) scintigraphy. These patients (4 F / 3 M), aged from 27 to 74 years (average age, 54 years), were treated by total and ganglionic curettage for papillary cancer of thyroid. Their evolutive surveillance extended from 1 to 24 years (on average, 8.4 years) and they received curative cumulated 131 I activities of 13 to 26 GBq. Each of them benefited by an osseous scintigraphy, of a cervico-thoraco-abdominal TDM and of a 111 In Pentetreotide SSR. The SSR was positive for 4/7 patients showing cervico-mediastinal fixations, the localizations being not detected by TDM. The osseous scintigraphy revealed once to be positive showing a costal lesion already detected by SSR. Cervical non-palpable adenopathies were detected by TDM for one patient. The anatomical-pathological analysis confirmed their thyroid origin. For other two patients the TDM showed suspect pulmonary nodules. These cervical and pulmonary localization were not detected by SSR. The SSR + TDM couple was positive for 6/7 patients. In conclusion, in this series the sensitivity of SSR was estimated to be 57%. Besides, the results obtained showed a net complementarity between the detection performances of SSR and TDM

  1. Endothelin receptor antagonist and airway dysfunction in pulmonary arterial hypertension

    Directory of Open Access Journals (Sweden)

    Borst Mathias M

    2009-12-01

    Full Text Available Abstract Background In idiopathic pulmonary arterial hypertension (IPAH, peripheral airway obstruction is frequent. This is partially attributed to the mediator dysbalance, particularly an excess of endothelin-1 (ET-1, to increased pulmonary vascular and airway tonus and to local inflammation. Bosentan (ET-1 receptor antagonist improves pulmonary hemodynamics, exercise limitation, and disease severity in IPAH. We hypothesized that bosentan might affect airway obstruction. Methods In 32 IPAH-patients (19 female, WHO functional class II (n = 10, III (n = 22; (data presented as mean ± standard deviation pulmonary vascular resistance (11 ± 5 Wood units, lung function, 6 minute walk test (6-MWT; 364 ± 363.7 (range 179.0-627.0 m, systolic pulmonary artery pressure, sPAP, 79 ± 19 mmHg, and NT-proBNP serum levels (1427 ± 2162.7 (range 59.3-10342.0 ng/L were measured at baseline, after 3 and 12 months of oral bosentan (125 mg twice per day. Results and Discussion At baseline, maximal expiratory flow at 50 and 25% vital capacity were reduced to 65 ± 25 and 45 ± 24% predicted. Total lung capacity was 95.6 ± 12.5% predicted and residual volume was 109 ± 21.4% predicted. During 3 and 12 months of treatment, 6-MWT increased by 32 ± 19 and 53 ± 69 m, respectively; p Conclusion This study gives first evidence in IPAH, that during long-term bosentan, improvement of hemodynamics, functional parameters or serum biomarker occur independently from persisting peripheral airway obstruction.

  2. Icatibant, a new bradykinin-receptor antagonist, in hereditary angioedema.

    Science.gov (United States)

    Cicardi, Marco; Banerji, Aleena; Bracho, Francisco; Malbrán, Alejandro; Rosenkranz, Bernd; Riedl, Marc; Bork, Konrad; Lumry, William; Aberer, Werner; Bier, Henning; Bas, Murat; Greve, Jens; Hoffmann, Thomas K; Farkas, Henriette; Reshef, Avner; Ritchie, Bruce; Yang, William; Grabbe, Jürgen; Kivity, Shmuel; Kreuz, Wolfhart; Levy, Robyn J; Luger, Thomas; Obtulowicz, Krystyna; Schmid-Grendelmeier, Peter; Bull, Christian; Sitkauskiene, Brigita; Smith, William B; Toubi, Elias; Werner, Sonja; Anné, Suresh; Björkander, Janne; Bouillet, Laurence; Cillari, Enrico; Hurewitz, David; Jacobson, Kraig W; Katelaris, Constance H; Maurer, Marcus; Merk, Hans; Bernstein, Jonathan A; Feighery, Conleth; Floccard, Bernard; Gleich, Gerald; Hébert, Jacques; Kaatz, Martin; Keith, Paul; Kirkpatrick, Charles H; Langton, David; Martin, Ludovic; Pichler, Christiane; Resnick, David; Wombolt, Duane; Fernández Romero, Diego S; Zanichelli, Andrea; Arcoleo, Francesco; Knolle, Jochen; Kravec, Irina; Dong, Liying; Zimmermann, Jens; Rosen, Kimberly; Fan, Wing-Tze

    2010-08-05

    Hereditary angioedema is characterized by recurrent attacks of angioedema of the skin, larynx, and gastrointestinal tract. Bradykinin is the key mediator of symptoms. Icatibant is a selective bradykinin B2 receptor antagonist. In two double-blind, randomized, multicenter trials, we evaluated the effect of icatibant in patients with hereditary angioedema presenting with cutaneous or abdominal attacks. In the For Angioedema Subcutaneous Treatment (FAST) 1 trial, patients received either icatibant or placebo; in FAST-2, patients received either icatibant or oral tranexamic acid, at a dose of 3 g daily for 2 days. Icatibant was given once, subcutaneously, at a dose of 30 mg. The primary end point was the median time to clinically significant relief of symptoms. A total of 56 and 74 patients underwent randomization in the FAST-1 and FAST-2 trials, respectively. The primary end point was reached in 2.5 hours with icatibant versus 4.6 hours with placebo in the FAST-1 trial (P=0.14) and in 2.0 hours with icatibant versus 12.0 hours with tranexamic acid in the FAST-2 trial (P<0.001). In the FAST-1 study, 3 recipients of icatibant and 13 recipients of placebo needed treatment with rescue medication. The median time to first improvement of symptoms, as assessed by patients and by investigators, was significantly shorter with icatibant in both trials. No icatibant-related serious adverse events were reported. In patients with hereditary angioedema having acute attacks, we found a significant benefit of icatibant as compared with tranexamic acid in one trial and a nonsignificant benefit of icatibant as compared with placebo in the other trial with regard to the primary end point. The early use of rescue medication may have obscured the benefit of icatibant in the placebo trial. (Funded by Jerini; ClinicalTrials.gov numbers, NCT00097695 and NCT00500656.)

  3. A Pharmacokinetic/Pharmacodynamic Study of the Glucocorticoid Receptor Antagonist Mifepristone Combined with Enzalutamide in Castrate Resistant Prostate Cancer

    Science.gov (United States)

    2015-12-01

    AWARD NUMBER: W81XWH-14-1-0021 TITLE: A Pharmacokinetic/Pharmacodynamic Study of the Glucocorticoid Receptor Antagonist Mifepristone Combined...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER A Pharmacokinetic/Pharmacodynamic Study of the Glucocorticoid Receptor Antagonist Mifepristone Combined...way it adapts is by upregulating another hormone receptor, the glucocorticoid receptor (GR), which may compensate for diminished AR activity. The

  4. Receptor PET/CT for determining the somatostatin receptor status of neuroendocrine tumors before and after peptide receptor radionuclide therapy (PRRT): Clinical experience after 1,500 studies

    International Nuclear Information System (INIS)

    Baum, R.P.; Prasad, V.; Leonhardi, J.; Kroeger, R.; Wortmann, R.; Mueller, D.

    2007-01-01

    Full text: The octapeptide [DOTA]-1-Nal3-octreotide (DOTA-NOC) has 3 to 4 times higher binding affinity to sstr2 than DOTATOC (Wild 2003). We labeled this peptide with the Ga-68 (t1/2 68 min) and used it in pts with metastatic NET before/after PRRT for evaluating the sstr status by semiquantitative PET/CT imaging. Methods: Ga-68 was eluted from a Ge-68/Ga-68 generator using 0.1 M HCl. Following purifications, Ga-68 was eluted into a labeling vial containing 0.05 mg DOTA-NOC. Radiolabeling yields of >80% were achieved within 15 min at >95C. After purification (C18 cartridge) and a final elution, 370-700 MBq of Ga-68 DOTA-NOC were obtained with 100% radiochemical purity within 20 min (about 70% yield). Results: 1,500 PET/CT studies were performed in pts with histologically proven NET and progressive metastases before and after PRRT. Acquisition was started 20-270 min after injection of a mean of 100 MBq (46-260 MBq) Ga-68 DOTA-NOC using an LSO-based PET/CT (biograph DUO, Siemens). SUV were determined for all tumor lesions and normal tissues. SUV in metastases was as high as 152 whereas normal tissue was in the range of 0.4 (lung) to 33 (spleen). Outstanding PET/CT images of all known tumor lesions and in addition very small lymph node and bone metastases (<5 mm) were easily visualized as early as 20 min p.i. Clearly more lesions were detected as compared to Tc-99m EDDA-HYNIC-TOC or In-111 DOTA-NOC SPECT or as seen on CT or MRI images (especially regarding lymph node metastases, bone lesions and unknown primaries). Conclusions: Molecular receptor PET/CT imaging using the Ga-68-labeled somatostatin analogue DOTA-NOC detects neuroendocrine tumor metastases with very high diagnostic sensitivity and specificity. Semiquantitative uptake measurements (SUV) allow predicting the tumor uptake of Y-90 or Lu-177- labeled peptides before PRRT and are highly useful for therapy control to determine the 'molecular tumor response' which can precede the morphologic responses by months

  5. From Chemotherapy-Induced Emesis to Neuroprotection: Therapeutic Opportunities for 5-HT3 Receptor Antagonists.

    Science.gov (United States)

    Fakhfouri, Gohar; Mousavizadeh, Kazem; Mehr, Sharam Ejtemaei; Dehpour, Ahmad Reza; Zirak, Mohammad Reza; Ghia, Jean-Eric; Rahimian, Reza

    2015-12-01

    5-HT3 receptor antagonists are extensively used as efficacious agents in counteracting chemotherapy-induced emesis. Recent investigations have shed light on other potential effects (analgesic, anxiolytic, and anti-psychotic). Some studies have reported neuroprotective properties for the 5-HT3 receptor antagonists in vitro and in vivo. When administered to Aβ-challenged rat cortical neurons, 5-HT3 receptor antagonists substantially abated apoptosis, elevation of cytosolic Ca(2), glutamate release, reactive oxygen species (ROS) generation, and caspase-3 activity. In addition, in vivo studies show that 5-HT3 receptor antagonists possess, alongside their anti-emetic effects, notable immunomodulatory properties in CNS. We found that pretreatment with tropisetron significantly improved neurological deficits and diminished leukocyte transmigration into the brain, TNF-α level, and brain infarction in a murine model of embolic stroke. Our recent investigation revealed that tropisetron protects against Aβ-induced neurotoxicity in vivo through both 5-HT3 receptor-dependent and -independent pathways. Tropisetron, in vitro, was found to be an efficacious inhibitor of the signaling pathway leading to the activation of pro-inflammatory NF-κB, a transcription factor pivotal to the upregulation of several neuroinflammatory mediators in brain. This mini review summarizes novel evidence concerning effects of 5-HT3 antagonists and their possible mechanisms of action in ameliorating neurodegenerative diseases including Alzheimer, multiple sclerosis, and stroke. Further, we discuss some newly synthesized 5-HT3 receptor antagonists with dual properties of 5-HT3 receptor blockade/alpha-7 nicotinic receptor activator and their potential in management of memory impairment. Since 5-HT3 receptor antagonists possess a large therapeutic window, they can constitute a scaffold for design and synthesis of new neuroprotective medications.

  6. Unicentric Castleman's Disease Revealed by 18F-FDG PET/CT and Somatostatin Receptor Scintigraphy With 99mTc-HYNIC-TOC.

    Science.gov (United States)

    Luo, Yaping; Wang, Ling; Pan, Qingqing; Ma, Yanru; Li, Fang

    2018-07-01

    A 51-year-old woman with a history of hypertension and abdominal pain was found with a retroperitoneal mass. The mass had intense enhancement in contrast-enhanced CT, and it showed a moderate degree of increased FDG uptake in PET/CT. The mass was also positive in somatostatin receptor scintigraphy with Tc-HYNIC-TOC, but it was negative in I-MIBG scan. The histopathological result after surgical resection of the mass confirmed the diagnosis of Castleman's disease, the hyaline vascular variant.

  7. Current knowledge on the sensitivity of the 68Ga-somatostatin receptor positron emission tomography and the SUVmax reference range for management of pancreatic neuroendocrine tumours

    OpenAIRE

    Virgolini, Irene; Gabriel, Michael; Kroiss, Alexander; von Guggenberg, Elisabeth; Prommegger, Rupert; Warwitz, Boris; Nilica, Bernhard; Roig, llanos Geraldo; Rodrigues, Margarida; Uprimny, Christian

    2016-01-01

    Physiologically increased pancreatic uptake at the head/uncinate process is observed in more than one-third of patients after injection of one of the three 68Ga-labelled octreotide-based peptides used for somatostatin (sst) receptor (r) imaging. There are minor differences between these 68Ga-sstr-binding peptides in the imaging setting. On 68Ga-sstr-imaging the physiological uptake can be diffuse or focal and usually remains stable over time. Differences in the maximal standardised uptake val...

  8. Guideline for PET/CT imaging of neuroendocrine neoplasms withGa-DOTA-conjugated somatostatin receptor targeting peptides andF-DOPA

    DEFF Research Database (Denmark)

    Bozkurt, Murat Fani; Virgolini, Irene; Balogova, Sona

    2017-01-01

    PURPOSE & METHODS: Neuroendocrine neoplasms are a heterogenous group of tumours, for which nuclear medicine plays an important role in the diagnostic work-up as well as in the targeted therapeutic options. This guideline is aimed to assist nuclear medicine physicians in recommending, performing......, reporting and interpreting the results of somatostatin receptor (SSTR) PET/CT imaging using68Ga-DOTA-conjugated peptides, as well as18F-DOPA imaging for various neuroendocrine neoplasms. RESULTS & CONCLUSION: The previous procedural guideline by EANM regarding the use PET/CT tumour imaging with68Ga...

  9. Nonpeptidic angiotensin II AT₁ receptor antagonists derived from 6-substituted aminocarbonyl and acylamino benzimidazoles.

    Science.gov (United States)

    Zhang, Jun; Wang, Jin-Liang; Yu, Wei-Fa; Zhou, Zhi-Ming; Tao, Wen-Chang; Wang, Yi-Cheng; Xue, Wei-Zhe; Xu, Di; Hao, Li-Ping; Han, Xiao-Feng; Fei, Fan; Liu, Ting; Liang, Ai-Hua

    2013-11-01

    Both 6-substituted aminocarbonyl and acylamino benzimidazole derivatives were designed and synthesized as nonpeptidic angiotensin II AT₁ receptor antagonists. Compounds 6f, 6g, 11e, 11f, 11g, and 12 showed nanomolar AT₁ receptor binding affinity and high AT₁ receptor selectivity over AT₂ receptor in a preliminary pharmacological evaluation. Among them, the two most active compounds 6f (AT₁ IC₅₀ = 3 nM, AT₂ IC₅₀ > 10,000 nM, PA₂ = 8.51) and 11g (AT₁ IC₅₀ = 0.1 nM, AT₂ IC₅₀ = 149 nM, PA₂ = 8.43) exhibited good antagonistic activity in isolated rabbit aortic strip functional assay. In addition, they were orally active AT₁ receptor antagonists in spontaneous hypertensive rats. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  10. Peptide receptor radionuclide therapy of Merkel cell carcinoma using 177lutetium-labeled somatostatin analogs in combination with radiosensitizing chemotherapy. A potential novel treatment based on molecular pathology

    International Nuclear Information System (INIS)

    Salavati, A.; Prasad, V.; Baum, R.P.; Schneider, C.P.; Herbst, R.

    2012-01-01

    Few studies have been published on the safety and feasibility of synchronous use of peptide receptor radionuclide therapy (PRRNT), as source of internal radiation therapy, in combination with chemotherapy. In this study we reported a 53-year-old man with stage IV Merkel cell carcinoma (MCC), who underwent synchronous internal radiation therapy and chemotherapy. Based on presumable poor prognosis with chemotherapy only, functional similarities of MCC with other neuroendocrine tumors and available evidence of effectiveness and safety of synchronous use of external beam radiation therapy and chemotherapy in treatment of high-risk MCC patients, our interdisciplinary neuroendocrine tumor board recommended him to add PRRNT to his ongoing chemotherapy. He received 2 courses of 177 Lu-DOTATATE(1, 4, 7, 10-Tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid-1-D-Phe1-Tyr3-Thr8-octreotide) in combination with ongoing 8 cycles of liposomal doxorubicin based on standard protocols. Response to therapy was evaluated by 18 F-fluorodeoxyglucose ( 18 F-FDG) and 68 gallium-somatostatin-receptor PET/CT. There was an impressive improvement of the clinical symptoms. However, follow-up positron emission tomography (PET)/CT studies showed mixed pattern of response. Synchronous use of PRRNT and radiosensitizing chemotherapy seems safe and feasible in high risk MCC patients, however, further prospective studies and clinical trials are warranted to provide reliable evidence of possible pitfalls and effectiveness of PRRNT and 68 Ga-somatostatin-receptor PET/CT in the management of MCC. (author)

  11. Palliation of bone cancer pain by antagonists of platelet-activating factor receptors.

    Directory of Open Access Journals (Sweden)

    Katsuya Morita

    Full Text Available Bone cancer pain is the most severe among cancer pain and is often resistant to current analgesics. Thus, the development of novel analgesics effective at treating bone cancer pain are desired. Platelet-activating factor (PAF receptor antagonists were recently demonstrated to have effective pain relieving effects on neuropathic pain in several animal models. The present study examined the pain relieving effect of PAF receptor antagonists on bone cancer pain using the femur bone cancer (FBC model in mice. Animals were injected with osteolytic NCTC2472 cells into the tibia, and subsequently the effects of PAF receptor antagonists on pain behaviors were evaluated. Chemical structurally different type of antagonists, TCV-309, BN 50739 and WEB 2086 ameliorated the allodynia and improved pain behaviors such as guarding behavior and limb-use abnormalities in FBC model mice. The pain relieving effects of these antagonists were achieved with low doses and were long lasting. Blockade of spinal PAF receptors by intrathecal injection of TCV-309 and WEB 2086 or knockdown of the expression of spinal PAF receptor protein by intrathecal transfer of PAF receptor siRNA also produced a pain relieving effect. The amount of an inducible PAF synthesis enzyme, lysophosphatidylcholine acyltransferase 2 (LPCAT2 protein significantly increased in the spinal cord after transplantation of NCTC 2472 tumor cells into mouse tibia. The combination of morphine with PAF receptor antagonists develops marked enhancement of the analgesic effect against bone cancer pain without affecting morphine-induced constipation. Repeated administration of TCV-309 suppressed the appearance of pain behaviors and prolonged survival of FBC mice. The present results suggest that PAF receptor antagonists in combination with, or without, opioids may represent a new strategy for the treatment of persistent bone cancer pain and improve the quality of life of patients.

  12. Effects of sigma(1) receptor ligand MS-377 on D(2) antagonists-induced behaviors.

    Science.gov (United States)

    Karasawa, Jun-ichi; Takahashi, Shinji; Takagi, Kaori; Horikomi, Kazutoshi

    2002-10-01

    (R)-(+)-1-(4-Chlorophenyl)-3-[4-(2-methoxyethyl)piperazin-1-yl]methyl-2-pyrrolidinone L-tartrate (MS-377) is a novel antipsychotic agent with selective and high affinity for sigma(1) receptor. The present study was carried out to clarify the interaction of MS-377 with dopamine D(2) receptor antagonists (D(2) antagonists) in concurrent administration, and then the involvement of sigma receptors in the interaction. The effects of MS-377 on haloperidol- or sultopride-induced inhibition of apomorphine-induced climbing behavior and catalepsy were investigated in mice and rats, respectively. In addition, the effects of (+)-SKF-10,047 and SA4503, both of which are sigma receptor agonists, and WAY-100,635, which is a 5-HT(1A) receptor antagonist, on the interaction due to the concurrent use were also investigated. MS-377 potentiated the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior in a dose-dependent manner. In contrast, MS-377 did not affect the catalepsy induction by these drugs. The potentiation of the inhibitory effects of haloperidol or sultopride on apomorphine-induced climbing behavior by MS-377 was not inhibited by WAY-100,635, but was inhibited by (+)-SKF-10,047 and SA4503. These findings showed that MS-377 potentiates the efficacy of D(2) antagonists, but it does not deteriorate the adverse effect. Moreover, sigma(1) receptors are involved in this potentiation of the efficacy of D(2) antagonists by MS-377.

  13. Design and Synthesis of Benzimidazoles As Novel Corticotropin-Releasing Factor 1 Receptor Antagonists.

    Science.gov (United States)

    Mochizuki, Michiyo; Kori, Masakuni; Kobayashi, Katsumi; Yano, Takahiko; Sako, Yuu; Tanaka, Maiko; Kanzaki, Naoyuki; Gyorkos, Albert C; Corrette, Christopher P; Cho, Suk Young; Pratt, Scott A; Aso, Kazuyoshi

    2016-03-24

    Benzazole derivatives with a flexible aryl group bonded through a one-atom linker as a new scaffold for a corticotropin-releasing factor 1 (CRF1) receptor antagonist were designed, synthesized, and evaluated. We expected that structural diversity could be expanded beyond that of reported CRF1 receptor antagonists. In a structure-activity relationship study, 4-chloro-N(2)-(4-chloro-2-methoxy-6-methylphenyl)-1-methyl-N(7),N(7)-dipropyl-1H-benzimidazole-2,7-diamine 29g had the most potent binding activity against a human CRF1 receptor and the antagonistic activity (IC50 = 9.5 and 88 nM, respectively) without concerns regarding cytotoxicity at 30 μM. Potent CRF1 receptor-binding activity in brain in an ex vivo test and suppression of stress-induced activation of the hypothalamus-pituitary-adrenocortical (HPA) axis were also observed at 138 μmol/kg of compound 29g after oral administration in mice. Thus, the newly designed benzimidazole 29g showed in vivo CRF1 receptor antagonistic activity and good brain penetration, indicating that it is a promising lead for CRF1 receptor antagonist drug discovery research.

  14. Role of Transient Receptor Potential Ankyrin 1 Ion Channel and Somatostatin sst4 Receptor in the Antinociceptive and Anti-inflammatory Effects of Sodium Polysulfide and Dimethyl Trisulfide

    Directory of Open Access Journals (Sweden)

    István Z. Bátai

    2018-02-01

    Full Text Available Transient receptor potential ankyrin 1 (TRPA1 non-selective ligand-gated cation channels are mostly expressed in primary sensory neurons. Polysulfides (POLYs are Janus-faced substances interacting with numerous target proteins and associated with both protective and detrimental processes. Activation of TRPA1 in sensory neurons, consequent somatostatin (SOM liberation and action on sst4 receptors have recently emerged as mediators of the antinociceptive effect of organic trisulfide dimethyl trisulfide (DMTS. In the frame of the present study, we set out to compare the participation of this mechanism in antinociceptive and anti-inflammatory effects of inorganic sodium POLY and DMTS in carrageenan-evoked hind-paw inflammation. Inflammation of murine hind paws was induced by intraplantar injection of carrageenan (3% in 30 µL saline. Animals were treated intraperitoneally with POLY (17 µmol/kg or DMTS (250 µmol/kg or their respective vehicles 30 min prior paw challenge and six times afterward every 60 min. Mechanical pain threshold and swelling of the paws were measured by dynamic plantar aesthesiometry and plethysmometry at 2, 4, and 6 h after initiation of inflammation. Myeloperoxidase (MPO activity in the hind paws were detected 6 h after challenge by luminescent imaging. Mice genetically lacking TRPA1 ion channels, sst4 receptors and their wild-type counterparts were used to examine the participation of these proteins in POLY and DMTS effects. POLY counteracted carrageenan-evoked mechanical hyperalgesia in a TRPA1 and sst4 receptor-dependent manner. POLY did not influence paw swelling and MPO activity. DMTS ameliorated all examined inflammatory parameters. Mitigation of mechanical hyperalgesia and paw swelling by DMTS were mediated through sst4 receptors. These effects were present in TRPA1 knockout animals, too. DMTS inhibited MPO activity with no participation of the sensory neuron–SOM axis. While antinociceptive effects of

  15. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral cir...

  16. AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

    OpenAIRE

    Terry W. Moody; Nicole Tashakkori; Samuel A. Mantey; Paola Moreno; Irene Ramos-Alvarez; Marcello Leopoldo; Robert T. Jensen

    2017-01-01

    While peptide antagonists for the gastrin-releasing peptide receptor (BB2R), neuromedin B receptor (BB1R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar ...

  17. A Pharmacokinetic/Pharmacodynamic Study of the Glucocorticoid Receptor Antagonist Mifepristone Combined with Enzalutamide in Castrate-Resistant Prostate Cancer

    Science.gov (United States)

    2017-12-01

    Receptor Antagonist Mifepristone Combined with Enzalutamide in Castrate-Resistant Prostate Cancer 5a. CONTRACT NUMBER 5b. GRANT NUMBER... receptor (AR) targeted therapies, prostate cancer adapts. One way it adapts is by upregulating another hormone receptor , the glucocorticoid receptor (GR...trial. 15. SUBJECT TERMS Castration resistant prostate cancer (CRPC); Androgen Receptor (AR); Glucocorticoid receptor (GR); Enzalutamide;

  18. Role of 68Ga somatostatin receptor PET/CT in the detection of endogenous hyperinsulinaemic focus: an explorative study

    International Nuclear Information System (INIS)

    Prasad, Vikas; Sainz-Esteban, Aurora; Arsenic, Ruza; Ploeckinger, Ursula; Denecke, Timm; Pape, Ulrich-Frank; Pavel, Marianne; Pascher, Andreas; Kuehnen, Peter; Blankenstein, Oliver

    2016-01-01

    To explore the role of 68 Ga-DOTATATE/DOTATOC PET/CT (SR PET/CT) in patients with suspicion of or histopathologically proven pancreatogenic hyperinsulinaemic hypoglycaemia. We included 13 patients with histopathologically proven or a high clinical suspicion of pancreatogenic hyperinsulinaemia. All the patients underwent a SR PET/CT scan. The results were correlated with histopathological findings. Normalization of blood glucose levels after resection of the pancreatic lesion, as well as a cytological and/or pathological diagnosis of insulinoma, was considered the diagnostic gold standard for insulinoma. The diagnosis of nesidioblastosis was based on exclusion of an insulinoma and conclusive pathological examination of a segment of the pancreas. Malignant insulinoma was defined as the presence of locoregional or distant metastases. Based on histopathology, 13 patients were found to have pancreatic hyperinsulinaemia: two patients had malignant insulinoma, eight had nonmetastasized insulinoma, and three had nesidioblastosis. SR PET was positive in 11 of the 13 patients (84.6 %) with a final diagnosis of endogenous pancreatic hypoglycaemia. Histopathological staining confirmed 16 foci of hyperinsulinism (insulin positivity). SR PET detected 14 of the 16 lesions, resulting in a sensitivity of 87 %. One intrapancreatic spleen was falsely diagnosed as insulinoma focus on SR PET, resulting in positive predictive value of 93.3 %. Immunohistochemical staining of somatostatin receptor (SSR) subtype 2a was available in ten specimens: two nesidioblastosis, and seven benign and one malignant insulinoma. Eight out of the ten specimens (80 %) stained strongly to moderately positive. Seven of the eight SSR2a-positive lesions were picked up on SR PET. Based on the results of SR PET/CT, nine patients achieved complete remission of the hypoglycaemic events during follow-up. This explorative study suggests that SR PET in combination with CT may play a significant role in the detection

  19. In vivo binding of [68Ga]-DOTATOC to somatostatin receptors in neuroendocrine tumours - impact of peptide mass

    International Nuclear Information System (INIS)

    Velikyan, Irina; Sundin, Anders; Eriksson, Barbro; Lundqvist, Hans; Soerensen, Jens; Bergstroem, Mats; Langstroem, Bengt

    2010-01-01

    Objectives: The aim of this pilot study was to explore the impact of peptide mass on binding of [ 68 Ga]-DOTATOC to neuroendocrine tumour somatostatin receptors in vivo using a tracer of variable specific radioactivity (SRA) and to show the logistic feasibility of sequential PET scans in the same patient. Material and Methods: Nine patients with gastroenteropancreatic neuroendocrine tumours were included. Six of them underwent three sequential PET-CT examinations with intravenous injections of [ 68 Ga]-DOTATOC proceeded by 0, 50 and 250 or 500 μg of octreotide, administered 10 min before the tracer. Three patients were examined by dynamic and static PET/CT for pharmacokinetic and dosimetric calculations. The [ 68 Ga]-DOTATOC synthesis included preconcentration and purification of the generator eluate and microwave heating in a semi-automated in-house procedure. Results: [ 68 Ga]-DOTATOC synthesis and quality control were accomplished within 30 min and radiochemical purity was >95%. The tracer accumulation in the tumours varied and depended on the total amount of the administered peptide. In five of six patients, the highest tumour-to-normal tissue ratio was found when 50 μg of octreotide was preadministered. One patient showed a continuously increasing tumour uptake. Dosimetrically, a large variation in organ doses was found (kidney: 0.086-0.168 mSv/MBq; liver: 0.026-0.096 mSv/MBq; spleen: 0.046-0.226 mSv/MBq). The effective dose (0.015, 0.0067 and 0.0042 mSv/MBq) was correlated to the total amount of decays. Discussion: Three sequential PET-CT examinations using 68 Ga-based tracer was carried out in 1 day. The use of high SRA [ 68 Ga]-DOTATOC and unlabelled octreotide indicates an optimal mass leading to better image contrast. [ 68 Ga]-DOTATOC-PET-CT employing variable SRA may be utilised for accurate quantification of tumour uptake with subsequent dosimetry for personalized therapy management.

  20. In vivo binding of [{sup 68}Ga]-DOTATOC to somatostatin receptors in neuroendocrine tumours - impact of peptide mass

    Energy Technology Data Exchange (ETDEWEB)

    Velikyan, Irina [Department of Biochemistry and Organic Chemistry, BMC, Uppsala University, Box 599, SE-751 24 Uppsala (Sweden); Uppsala Applied Science Lab, GEMS PET Systems, GE Healthcare, SE-752 28 Uppsala (Sweden); Sundin, Anders [Department of Radiology, Karolinska University Hospital, SE-171 76 Stockholm (Sweden); Eriksson, Barbro [Department of Endocrine Oncology, Uppsala University Hospital, SE-751 85 Uppsala (Sweden); Lundqvist, Hans [Department of Oncology, Radiology and Clinical Immunology, Uppsala University, SE-751 85 Uppsala (Sweden); Soerensen, Jens [Department of Medicinal Sciences, Clinical Physiology and Nuclear Medicine, Uppsala University Hospital, SE-751 85 Uppsala (Sweden); Bergstroem, Mats [Department of Pharmaceutical Biosciences, Uppsala Biomedical Centre, Uppsala University, Uppsala (Sweden); Langstroem, Bengt [Department of Biochemistry and Organic Chemistry, BMC, Uppsala University, Box 599, SE-751 24 Uppsala (Sweden)], E-mail: langstrom@biorg.uu.se

    2010-04-15

    Objectives: The aim of this pilot study was to explore the impact of peptide mass on binding of [{sup 68}Ga]-DOTATOC to neuroendocrine tumour somatostatin receptors in vivo using a tracer of variable specific radioactivity (SRA) and to show the logistic feasibility of sequential PET scans in the same patient. Material and Methods: Nine patients with gastroenteropancreatic neuroendocrine tumours were included. Six of them underwent three sequential PET-CT examinations with intravenous injections of [{sup 68}Ga]-DOTATOC proceeded by 0, 50 and 250 or 500 {mu}g of octreotide, administered 10 min before the tracer. Three patients were examined by dynamic and static PET/CT for pharmacokinetic and dosimetric calculations. The [{sup 68}Ga]-DOTATOC synthesis included preconcentration and purification of the generator eluate and microwave heating in a semi-automated in-house procedure. Results: [{sup 68}Ga]-DOTATOC synthesis and quality control were accomplished within 30 min and radiochemical purity was >95%. The tracer accumulation in the tumours varied and depended on the total amount of the administered peptide. In five of six patients, the highest tumour-to-normal tissue ratio was found when 50 {mu}g of octreotide was preadministered. One patient showed a continuously increasing tumour uptake. Dosimetrically, a large variation in organ doses was found (kidney: 0.086-0.168 mSv/MBq; liver: 0.026-0.096 mSv/MBq; spleen: 0.046-0.226 mSv/MBq). The effective dose (0.015, 0.0067 and 0.0042 mSv/MBq) was correlated to the total amount of decays. Discussion: Three sequential PET-CT examinations using {sup 68}Ga-based tracer was carried out in 1 day. The use of high SRA [{sup 68}Ga]-DOTATOC and unlabelled octreotide indicates an optimal mass leading to better image contrast. [{sup 68}Ga]-DOTATOC-PET-CT employing variable SRA may be utilised for accurate quantification of tumour uptake with subsequent dosimetry for personalized therapy management.

  1. Behavioral, biological, and chemical perspectives on targeting CRF1 receptor antagonists to treat alcoholism

    Science.gov (United States)

    Zorrilla, Eric P.; Heilig, Markus; de Wit, Harriet; Shaham, Yavin

    2013-01-01

    Background Alcohol use disorders are chronic disabling conditions for which existing pharmacotherapies have only modest efficacy. In the present review, derived from the 2012 Behavior, Biology and Chemistry “Translational Research in Addiction” symposium, we summarize the anti-relapse potential of corticotropin-releasing factor type 1 (CRF1) receptor antagonists to reduce negative emotional symptoms of acute and protracted alcohol withdrawal and stress-induced relapse to alcohol seeking. Methods We review the biology of CRF1 systems, the activity of CRF1 receptor antagonists in animal models of anxiolytic and antidepressant activity, and experimental findings in alcohol addiction models. We also update the clinical trial status of CRF1 receptor antagonists, including pexacerfont (BMS-562086), emicerfont (GW876008), verucerfont (GSK561679), CP316311, SSR125543A, R121919/NBI30775, R317573/19567470/CRA5626, and ONO-2333Ms. Finally, we discuss the potential heterogeneity and pharmacogenomics of CRF1 receptor pharmacotherapy for alcohol dependence. Results The evidence suggests that brain penetrant-CRF1 receptor antagonists have therapeutic potential for alcohol dependence. Lead compounds with clinically desirable pharmacokinetic properties now exist, and longer receptor residence rates (i.e., slow dissociation) may predict greater CRF1 receptor antagonist efficacy. Functional variants in genes that encode CRF system molecules, including polymorphisms in Crhr1 (rs110402, rs1876831, rs242938) and Crhbp genes (rs10055255, rs3811939) may promote alcohol seeking and consumption by altering basal or stress-induced CRF system activation. Conclusions Ongoing clinical trials with pexacerfont and verucerfont in moderately to highly severe dependent anxious alcoholics may yield insight as to the role of CRF1 receptor antagonists in a personalized medicine approach to treat drug or alcohol dependence. PMID:23294766

  2. Identification of Receptor Ligands and Receptor Subtypes Using Antagonists in a Capillary Electrophoresis Single-Cell Biosensor Separation System

    Science.gov (United States)

    Fishman, Harvey A.; Orwar, Owe; Scheller, Richard H.; Zare, Richard N.

    1995-08-01

    A capillary electrophoresis system with single-cell biosensors as a detector has been used to separate and identify ligands in complex biological samples. The power of this procedure was significantly increased by introducing antagonists that inhibited the cellular response from selected ligand-receptor interactions. The single-cell biosensor was based on the ligand-receptor binding and G-protein-mediated signal transduction pathways in PC12 and NG108-15 cell lines. Receptor activation was measured as increases in cytosolic free calcium ion concentration by using fluorescence microscopy with the intracellular calcium ion indicator fluo-3 acetoxymethyl ester. Specifically, a mixture of bradykinin (BK) and acetylcholine (ACh) was fractionated and the components were identified by inhibiting the cellular response with icatibant (HOE 140), a selective antagonist to the BK B_2 receptor subtype (B_2BK), and atropine, an antagonist to muscarinic ACh receptor subtypes. Structurally related forms of BK were also identified based on inhibiting B_2BK receptors. Applications of this technique include identification of endogenous BK in a lysate of human hepatocellular carcinoma cells (Hep G2) and screening for bioactivity of BK degradation products in human blood plasma. The data demonstrate that the use of antagonists with a single-cell biosensor separation system aids identification of separated components and receptor subtypes.

  3. Somatostatin receptor scintigraphy in patients with rheumatoid arthritis and secondary Sjögren's syndrome treated with Infliximab: a pilot study.

    Science.gov (United States)

    Anzola-Fuentes, L K; Chianelli, M; Galli, F; Glaudemans, A W J M; Martin Martin, L; Todino, V; Migliore, A; Signore, A

    2016-12-01

    Human T lymphocytes infiltrating tissues in autoimmune diseases are known to express somatostatin receptors amongst other activation markers. In this study, we evaluated whether somatostatin receptor scintigraphy (SRS) using a radiolabelled somatostatin analogue ((99m)Tc-EDDA/tricine-HYNIC-tyr(3)-octreotide ((99m)Tc-EDDA/HYNIC-TOC)) is able to detect the presence of immune-mediated processes in patients with rheumatoid arthritis and secondary Sjögren's syndrome. We also aimed to evaluate whether positivity to SRS was predictive of therapeutic response and if SRS could be used for monitoring the efficacy of immunomodulatory treatment. Eighteen patients with rheumatoid arthritis and secondary Sjögren's syndrome not responding to conventional treatment were recruited for treatment with infliximab, a monoclonal antibody against TNF-α. All patients had complete blood cell count, renal and liver function tests, measurements of ESR, CRP, ANA, ENA, and anti-dsDNA antibodies, functional salivary gland scintigraphy, labial biopsy, and ophthalmologic assessment with Schirmer's test and tear film break-up time (BUT). Diagnosis was made according to the revised criteria of the American-European Consensus Group. All patients underwent SRS at baseline and after 3-6 months of therapy with infliximab. Eleven out of 18 had repeat SRS images. Images of the salivary glands and major joints were acquired 3 h after injection of 370 MBq of (99m)Tc-EDDA/HYNIC-TOC. Image analysis was performed semi-quantitatively. All patients showed uptake of (99m)Tc-EDDA/HYNIC-TOC in the joints. Salivary glands also showed variable radiopharmaceutical uptake in 12 out of 18 patients, but all patients showed presence of lymphocytic infiltration at labial salivary gland biopsy. All patients, who repeated the study after treatment, showed significant reduction of somatostatin uptake in the joints but not in the salivary glands. SRS using (99m)Tc-EDDA/HYNIC-TOC may be a useful imaging tool to assess

  4. Examination of the somatostatin receptor status in non-medullary thyroid cancer; Untersuchungen zum Somatostatinrezeptor-Status bei nicht-medullaeren Schilddruesenkarzinomen

    Energy Technology Data Exchange (ETDEWEB)

    Goerges, R.; Brandt-Mainz, K.; Bockisch, A. [Essen Univ. (Gesamthochschule) (Germany). Klinik und Poliklinik fuer Nuklearmedizin; Kahaly, G. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Medizin - Endokrinologie und Stoffwechselerkrankungen; Mueller-Brand, J.; Maecke, H. [Kantonsspital Basel (Switzerland). Inst. fuer Nuklearmedizin; Walgenbach, S. [Mainz Univ. (Germany). Klinik und Poliklinik fuer Allgemein- und Abdominalchirurgie; Bruns, C. [Praeklinische Forschung Novartis, Basel (Switzerland); Andreas, J. [Universitaetsklinik Mainz (Germany). Klinik und Poliklinik fuer Nuklearmedizin

    1999-06-01

    Aim: Recent in-vitro and in-vivo studies demonstrated a somatostatin receptor expression in some non-medullary thyroid carcinomas. In this study we investigated the somatostatin receptor status for this particular tumor entity in a larger patient group. Subject and methods: We compared 131-iodine with 111-In-pentetreotide scans in 24 patients with metastasizing, non-medullary thyroid cancer. The findings were correlated with other imaging modalities. Additionally, we performed receptor autoradiography in one patient, octreotide therapy in another patient and administration of 90-Y- and 111-In-DOTATOC in 2 consecutive patients. Results: In the 15 patients with papillary or follicular carcinoma, 111-In-pentetreotide was inferior to 131-I in 8/15, equal in 1/15, and superior in 6/15 patients. In 8/9 of the patients with Huerthle cell cacinoma, metastases showed a 111-In-pentetreotide accumulation of various intensity, while 131-iodine scans were negative except for one patient. 111-In-pentetreotide was equal or superior compared to 201-Tl or 99m-Tc-sestamibi, but for the most part inferior in comparison with 18-F-FDG-PET. The findings of 111-In-pentetreotide scintigraphy correlated well with the receptor autoradiography and the accumulation of DOTATOC, but not with the therapeutic effect of `cold` octreotide on the thyroid cancer metastases. Conclusions: Several metastases of papillary and follicular carcinoma, and the majority of Huerthle cell cancer metastases can express somatostatin receptors. 111-In-pentetreotide scintigraphy is a promising tool for localization of metastases especially in Huerthle cell cancer or if PET is not available, and may be useful for selection of possible candidates, if therapeutic effective {beta}-emitting somatostatin analogues will be available for routine application. (orig.) [Deutsch] Ziel: in aktuellen In-vitro und In-vivo-Untersuchungen wurde eine Somatostatinrezeptor-Expression bei einigen nicht

  5. CCR5 receptor antagonists: discovery and SAR study of guanylhydrazone derivatives.

    Science.gov (United States)

    Wei, Robert G; Arnaiz, Damian O; Chou, Yuo-Ling; Davey, Dave; Dunning, Laura; Lee, Wheeseong; Lu, Shou-Fu; Onuffer, James; Ye, Bin; Phillips, Gary

    2007-01-01

    High throughput screening (HTS) led to the identification of the guanylhydrazone of 2-(4-chlorobenzyloxy)-5-bromobenzaldehyde as a CCR5 receptor antagonist. Initial modifications of the guanylhydrazone series indicated that substitution of the benzyl group at the para-position was well tolerated. Substitution at the 5-position of the central phenyl ring was critical for potency. Replacement of the guanylhydrazone group led to the discovery of a novel series of CCR5 antagonists.

  6. DOTA-NOC, a high-affinity ligand of somatostatin receptor subtypes 2, 3 and 5 for labelling with various radiometals

    International Nuclear Information System (INIS)

    Wild, Damian; Schmitt, Joerg S.; Ginj, Mihaela; Maecke, Helmut R.; Bernard, Bert F.; Krenning, Eric; Jong, Marion de; Wenger, Sandra; Reubi, Jean-Claude

    2003-01-01

    Earlier studies have shown that modification of the octapeptide octreotide in positions 3 and 8 may result in compounds with increased somatostatin receptor affinity that, if radiolabelled, display improved uptake in somatostatin receptor-positive tumours. The aim of a recent research study in our laboratory was to employ the parallel peptide synthesis approach by further exchanging the amino acid in position 3 of octreotide and coupling the macrocyclic chelator DOTA(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) to these peptides for labelling with radiometals like gallium-67 or -68, indium-111, yttrium-90 and lutetium-177. The purpose was to find radiopeptides with an improved somatostatin receptor binding profile in order to extend the spectrum of targeted tumours. A first peptide, [ 111 In, 90 Y-DOTA]-1-Nal 3 -octreotide ( 111 In, 90 Y-DOTA-NOC), was isolated which showed an improved profile. In III -DOTA-NOC exhibited the following IC 50 values (nM) when studied in competition with [ 125 I][Leu 8 , d-Trp 22 , Tyr 25 ]somatostatin-28 (values for Y III -DOTA-NOC are shown in parentheses): sstr2, 2.9±0.1 (3.3±0.2); sstr3, 8±2 (26±1.9); sstr5, 11.2±3.5 (10.4±1.6). Affinity towards sstr1 and 4 was very low or absent. In III -DOTA-NOC is superior to all somatostatin-based radiopeptides having this particular type of binding profile, including DOTA-lanreotide, and has three to four times higher binding affinity to sstr2 than In III ,Y III -DOTA-Tyr 3 -octreotide (In III ,Y III -DOTA-TOC). In addition, [ 111 In]DOTA-NOC showed a specific and high rate of internalization into AR4-2J rat pancreatic tumour cells which, after 4 h, was about two times higher than that of [ 111 In]DOTA-TOC and three times higher than that of [ 111 In]DOTA-octreotide ([ 111 In]DOTA-OC). The internalized radiopeptides were externalized intact upon 2 h of internalization followed by an acid wash. After 2-3 h of externalization a plateau is reached, indicating a steady

  7. Kinetic properties of 'dual' orexin receptor antagonists at OX1R and OX2R orexin receptors.

    Directory of Open Access Journals (Sweden)

    Gabrielle Elizabeth Callander

    2013-12-01

    Full Text Available Orexin receptor antagonists represent attractive targets for the development of drugs for the treatment of insomnia. Both efficacy and safety are crucial in clinical settings and thorough investigations of pharmacokinetics and pharmacodynamics can predict contributing factors such as duration of action and undesirable effects. To this end, we studied the interactions between various ‘dual’ orexin receptor antagonists and the orexin receptors, OX1R and OX2R, over time using saturation and competition radioligand binding with [3H]-BBAC ((S-N-([1,1'-biphenyl]-2-yl-1-(2-((1-methyl-1H-benzo[d]imidazol-2-ylthioacetylpyrrolidine-2-carboxamide. In addition, the kinetics of these compounds were investigated in cells expressing human, mouse and rat OX1R and OX2R using FLIPR® assays for calcium accumulation. We demonstrate that almorexant reaches equilibrium very slowly at OX2R, whereas SB-649868, suvorexant and filorexant may take hours to reach steady state at both orexin receptors. By contrast, compounds such as BBAC or the selective OX2R antagonist IPSU ((2-((1H-Indol-3-ylmethyl-9-(4-methoxypyrimidin-2-yl-2,9-diazaspiro[5.5]undecan-1-one bind rapidly and reach equilibrium very quickly in both binding and / or functional assays. Overall, the dual antagonists tested here tend to be rather unselective under non-equilibrium conditions and reach equilibrium very slowly. Once equilibrium is reached, each ligand demonstrates a selectivity profile that is however, distinct from the non-equilibrium condition. The slow kinetics of the dual antagonists tested suggest that in vitro receptor occupancy may be longer lasting than would be predicted. This raises questions as to whether pharmacokinetic studies measuring plasma or brain levels of these antagonists are accurate reflections of receptor occupancy in vivo.

  8. Drug safety is a barrier to the discovery and development of new androgen receptor antagonists.

    Science.gov (United States)

    Foster, William R; Car, Bruce D; Shi, Hong; Levesque, Paul C; Obermeier, Mary T; Gan, Jinping; Arezzo, Joseph C; Powlin, Stephanie S; Dinchuk, Joseph E; Balog, Aaron; Salvati, Mark E; Attar, Ricardo M; Gottardis, Marco M

    2011-04-01

    Androgen receptor (AR) antagonists are part of the standard of care for prostate cancer. Despite the almost inevitable development of resistance in prostate tumors to AR antagonists, no new AR antagonists have been approved for over a decade. Treatment failure is due in part to mutations that increase activity of AR in response to lower ligand concentrations as well as to mutations that result in AR response to a broader range of ligands. The failure to discover new AR antagonists has occurred in the face of continued research; to enable progress, a clear understanding of the reasons for failure is required. Non-clinical drug safety studies and safety pharmacology assays were performed on previously approved AR antagonists (bicalutamide, flutamide, nilutamide), next generation antagonists in clinical testing (MDV3100, BMS-641988), and a pre-clinical drug candidate (BMS-501949). In addition, non-clinical studies with AR mutant mice, and EEG recordings in rats were performed. Non-clinical findings are compared to disclosures of clinical trial results. As a drug class, AR antagonists cause seizure in animals by an off-target mechanism and are found in vitro to inhibit GABA-A currents. Clinical trials of candidate next generation AR antagonists identify seizure as a clinical safety risk. Non-clinical drug safety profiles of the AR antagonist drug class create a significant barrier to the identification of next generation AR antagonists. GABA-A inhibition is a common off-target activity of approved and next generation AR antagonists potentially explaining some side effects and safety hazards of this class of drugs. Copyright © 2010 Wiley-Liss, Inc.

  9. Functional antagonistic properties of clozapine at the 5-HT3 receptor.

    Science.gov (United States)

    Hermann, B; Wetzel, C H; Pestel, E; Zieglgänsberger, W; Holsboer, F; Rupprecht, R

    1996-08-23

    The atypical neuroleptic clozapine is thought to exert its psychopharmacological actions through a variety of neurotransmitter receptors. It binds preferentially to D4 and 5-HT2 receptors; however, little is known on it's interaction with the 5-HT3 receptor. Using a cell line stably expressing the 5-HT3 receptor, whole-cell voltage-clamp analysis revealed functional antagonistic properties of clozapine at low nanomolar concentrations in view of a binding affinity in the upper nanomolar range. Because the concentration of clozapine required for an interaction with the 5-HT3 receptor can be achieved with therapeutical doses, functional antagonistic properties at this ligand-gated ion channel may contribute to its unique psychopharmacological profile.

  10. Orexin 1 receptor antagonists in compulsive behaviour and anxiety: possible therapeutic use.

    Directory of Open Access Journals (Sweden)

    Emilio eMerlo-Pich

    2014-02-01

    Full Text Available Fifteen years after the discovery of hypocretin/orexin a large body of evidence has been collected supporting its critical role in the modulation of several regulatory physiological functions. While reduced levels of hypocretin/orexin were early on associated with narcolepsy, increased levels have been linked in recent years to pathological states of hypervigilance and, in particular, to insomnia. The filing to FDA of the dual-activity orexin receptor antagonist (DORA suvorexant for the indication of insomnia further corroborates the robustness of such evidences. However, as excessive vigilance is also typical of anxiety and panic episodes, as well as of abstinence and craving in substance misuse disorders, in this review we briefly discuss the evidence supporting the development of hypocretin/orexin receptor 1 (OX1 antagonists for these indications. Experiments using the OX1 antagonist SB-334867 and mutant mice have involved the OX1 receptor in mediating the compulsive reinstatement of drug seeking for ethanol, nicotine, cocaine, cannabinoids and morphine. More recently, data have been generated with the novel selective OX1 antagonists GSK1059865 and ACT-335827 on behavioural and cardiovascular response to stressors and panic-inducing agents in animals. Concluding, while waiting for pharmacologic data to become available in humans, risks and benefits for the development of an OX1 receptor antagonist for Binge Eating and Anxiety Disorders are discussed.

  11. Caffeine and Selective Adenosine Receptor Antagonists as New Therapeutic Tools for the Motivational Symptoms of Depression

    Directory of Open Access Journals (Sweden)

    Laura López-Cruz

    2018-06-01

    Full Text Available Major depressive disorder is one of the most common and debilitating psychiatric disorders. Some of the motivational symptoms of depression, such anergia (lack of self-reported energy and fatigue are relatively resistant to traditional treatments such as serotonin uptake inhibitors. Thus, new pharmacological targets are being investigated. Epidemiological data suggest that caffeine consumption can have an impact on aspects of depressive symptomatology. Caffeine is a non-selective adenosine antagonist for A1/A2A receptors, and has been demonstrated to modulate behavior in classical animal models of depression. Moreover, selective adenosine receptor antagonists are being assessed for their antidepressant effects in animal studies. This review focuses on how caffeine and selective adenosine antagonists can improve different aspects of depression in humans, as well as in animal models. The effects on motivational symptoms of depression such as anergia, fatigue, and psychomotor slowing receive particular attention. Thus, the ability of adenosine receptor antagonists to reverse the anergia induced by dopamine antagonism or depletion is of special interest. In conclusion, although further studies are needed, it appears that caffeine and selective adenosine receptor antagonists could be therapeutic agents for the treatment of motivational dysfunction in depression.

  12. Influence of PET/CT 68Ga somatostatin receptor imaging on proceeding with patients, who were previously diagnosed with 99mTc-EDDA/HYNIC-TOC SPECT.

    Science.gov (United States)

    Madrzak, Dorota; Mikołajczak, Renata; Kamiński, Grzegorz

    2016-01-01

    The aim of this study was the assessment of utility of somatostatin receptor scintigraphy (SRS) by SPECT imaging using 99mTc-EDDA/HYNIC-Tyr3-octreotide (99mTc-EDDA/HYNIC-TOC) in patients with neuroendocrine neoplasm (NEN) or suspected NEN, referred to Nuclear Medicine Dept. of Voivodship Specialty Center in Rzeszow. The selected group of patients was referred also to 68Ga PET/CT. The posed question was the ratio of patients for whom PET/CT with 68Ga would change their management. The distribution of somatostatin receptors was imaged using 99mTc-EDDA/HYNIC-TOC in 61 planar and SPECT studies between 13/05/2010 and 04/02/2013 in Nuclear Medicine Dept. of Voivodship Specialty Center in Rzeszow. The patient age was within a range of 17-80, with the average age of 57.6. The average age of women (65% of patients over-all) was 55.6 and the average age of men (35% of patients overall) was 61.4. In 46 participants (75% of the study group), that underwent SRS, NEN was documented using pathology tests. Selected patients were referred to PET/CT with 68Ga labeled somatostatin analogs, DOTATATE or DOTANOC. This study group consisted of 14 female and 10 male participants with age range of 35-77 and average age of 55.5 years. Patients were classified into 3 groups, as follows: detection - referral due to clinical symptoms and/or biochemical markers (CgA-Chromogranin A, IAA-indoleacetic acid) with the aim of primary diagnosis, staging - referral with the aim of assessment of tumor spread, and follow-up - assessment of the therapy. Out of 61 patients, 24 underwent both 99mTc-EDDA/HYNIC-Tyr3-octreotide SPECT and 68Ga PET/CT. The result of PET/CT was used as a basis for further evaluation. Therefore, the patients were divided into groups; true positive TP (confirmed presence of tissue somatostatin receptors with 68Ga PET/CT) and TN (68Ga PET/CT did not detect any changes and the results were comparable and had the same influence on treatment protocol). In case of SPECT, the results

  13. New octreotide derivatives for in vivo targeting of somatostatin receptor-positive tumors for Single Photon Emission Computed Tomography (SPECT) and Positron Emission Tomography (PET)

    International Nuclear Information System (INIS)

    Maecke, H.R.; Smith-Jones, P.; Maina, T.; Stolz, B.; Albert, R.; Bruns, C.; Reist, H.

    1993-01-01

    Two new modifications of the somatostatin analog octreotide, designed to hold the gallium isotopes 67 Ga and 68 Ga (DFO-SMS) and 99m Tc (PnAO-SMS) have been synthesized and evaluated in vitro and in vivo in tumor bearing rats. DFO-SMS can be labeled with 67 Ga 3+ and 68 Ga 3+ with high specific activity within less than 30 minutes in a ''cold kit'' type formulation. The labeled conjugate is stable under physiologgical conditions. Moreover the binding affinity to somatostatin receptors on rat brain cortex membranes was shown to be retained. In vivo fast tumor localization was demonstrated and the pharmacokinetics proved to be favourable as the main excretion route was via the kidneys. First PET studies with [ 68 Ga]-DFO-SMS showed a rapid accumulation in the tumor and a residence half-life at the tumor site of about 6 hours. PnAO-SMS can be labeled with 99m Tc with high radiochemical purity. In vivo the radiotracer accumulates well in the tumor but due to its high lipohilicity, its main excretion route is via the hepatobiliary system. (orig.)

  14. The discovery of the benzazepine class of histamine H3 receptor antagonists.

    Science.gov (United States)

    Wilson, David M; Apps, James; Bailey, Nicholas; Bamford, Mark J; Beresford, Isabel J; Briggs, Michael A; Calver, Andrew R; Crook, Barry; Davis, Robert P; Davis, Susannah; Dean, David K; Harris, Leanne; Heightman, Tom D; Panchal, Terry; Parr, Christopher A; Quashie, Nigel; Steadman, Jon G A; Schogger, Joanne; Sehmi, Sanjeet S; Stean, Tania O; Takle, Andrew K; Trail, Brenda K; White, Trevor; Witherington, Jason; Worby, Angela; Medhurst, Andrew D

    2013-12-15

    This Letter describes the discovery of a novel series of H3 receptor antagonists. The initial medicinal chemistry strategy focused on deconstructing and simplifying an early screening hit which rapidly led to the discovery of a novel series of H3 receptor antagonists based on the benzazepine core. Employing an H3 driven pharmacodynamic model, the series was then further optimised through to a lead compound that showed robust in vivo functional activity and possessed overall excellent developability properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Inverse agonist and neutral antagonist actions of synthetic compounds at an insect 5-HT1 receptor.

    Science.gov (United States)

    Troppmann, B; Balfanz, S; Baumann, A; Blenau, W

    2010-04-01

    5-Hydroxytryptamine (5-HT) has been shown to control and modulate many physiological and behavioural functions in insects. In this study, we report the cloning and pharmacological properties of a 5-HT(1) receptor of an insect model for neurobiology, physiology and pharmacology. A cDNA encoding for the Periplaneta americana 5-HT(1) receptor was amplified from brain cDNA. The receptor was stably expressed in HEK 293 cells, and the functional and pharmacological properties were determined in cAMP assays. Receptor distribution was investigated by RT-PCR and by immunocytochemistry using an affinity-purified polyclonal antiserum. The P. americana 5-HT(1) receptor (Pea5-HT(1)) shares pronounced sequence and functional similarity with mammalian 5-HT(1) receptors. Activation with 5-HT reduced adenylyl cyclase activity in a dose-dependent manner. Pea5-HT(1) was expressed as a constitutively active receptor with methiothepin acting as a neutral antagonist, and WAY 100635 as an inverse agonist. Receptor mRNA was present in various tissues including brain, salivary glands and midgut. Receptor-specific antibodies showed that the native protein was expressed in a glycosylated form in membrane samples of brain and salivary glands. This study marks the first pharmacological identification of an inverse agonist and a neutral antagonist at an insect 5-HT(1) receptor. The results presented here should facilitate further analyses of 5-HT(1) receptors in mediating central and peripheral effects of 5-HT in insects.

  16. Benzodiazepine receptor antagonists for acute and chronic hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Kjaergard, L L; Gluud, C

    2001-01-01

    The pathogenesis of hepatic encephalopathy is unknown. It has been suggested that liver failure leads to the accumulation of substances that bind to a receptor-complex in the brain resulting in neural inhibition which may progress to coma. Several trials have assessed benzodiazepine receptor...

  17. Union of 99m Tc-HYNIC-TOC at the somatostatin receptors in cells of pancreas cancer

    International Nuclear Information System (INIS)

    Rodriguez C, J.; Ramirez I, M.T.; Ferro F, G.; Pedraza L, M.

    2005-01-01

    The radiation toxic effects have been used in therapy however much 50 years. The absorbed radiation dose can be determined at cellular level using cancerous cell cultures. If the deposited In vitro radiation dose coming from similar activities of several therapeutic radiopharmaceuticals it can compare it will be possible to choose the therapeutic radiopharmaceutical that it offers better dosimetric characteristics for the patient. The objective of this original investigation was to determine the union percentage of the octreotide 99m Tc-HYNlC-TOC to the somatostatin receivers in cells of cancer pancreas as well as the internalization, externalization and cellular viability. It was used the octapeptide, (octreotide, TOC) labelled with 99m Tc by means of the HYNIC chelating agent (6-hydrazine pyridine-3-carboxylic acid) and 3 cellular lines of murine pancreas cancer (AR42J), of cancer of human pancreas (CAPAN) and of one negative cellular line for somatostatin receivers (WRL-68). The 99m Tc-HYNIC-TOC was compared against two negative proofs for somatostatin receivers: the peptide 99m Tc-UBI and the 99m TcO 4 . The cellular lines were conserved in the synthetic media Dulbecco-Eagle. After 2, 4 and 24 h of exhibition to the radiation, the cells are picked up and its are determined the viability by count in a Neubauer camera using tripan blue. In the same times it was calculated the union percentage of the radiopharmaceutical to the cells and the internalization (union to the cytoplasm) and the externalization (union to membrane receivers). With those figures it was calculated the absorbed radiation dose at cellular level. Results: At 4 hours the union percentage of the 99m Tc-HYNlC-TOC to the AR42-J cells was 6.83 times greater than for the WRL-68 control cells of human papilloma, (without receivers of the somatostatin) and for the CAPAN them 4 times greater than for the same cells used as negative control, for the case of the 99m Tc-UBI and the 99m TcO 4 one doesn

  18. Evaluation of (64)Cu-labeled DOTA-D-Phe(1)-Tyr (3)-octreotide ((64)Cu-DOTA-TOC) for imaging somatostatin receptor-expressing tumors.

    Science.gov (United States)

    Hanaoka, Hirofumi; Tominaga, Hideyuki; Yamada, Keiich; Paudyal, Pramila; Iida, Yasuhiko; Watanabe, Shigeki; Paudyal, Bishnuhari; Higuchi, Tetsuya; Oriuchi, Noboru; Endo, Keigo

    2009-08-01

    In-111 ((111)In)-labeled octreotide has been clinically used for imaging somatostatin receptor-positive tumors, and radiolabeled octreotide analogs for positron emission tomography (PET) have been developed. Cu-64 ((64)Cu; half-life, 12.7 h) is an attractive radionuclide for PET imaging and is produced with high specific activity using a small biomedical cyclotron. The aim of this study is to produce and fundamentally examine a (64)Cu-labeled octreotide analog, (64)Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-D: -Phe(1)-Tyr(3)-octreotide ((64)Cu-DOTA-TOC). (64)Cu produced using a biomedical cyclotron was reacted with DOTA-TOC for 30 min at 45 degrees C. The stability of (64)Cu-DOTA-TOC was evaluated in vitro (incubated with serum) and in vivo (blood collected after administration) by HPLC analysis. Biodistribution studies were performed in normal mice by administration of mixed solution of (64)Cu-DOTA-TOC and (111)In-DOTA-TOC and somatostatin receptor-positive U87MG tumor-bearing mice by administration of (64)Cu-DOTA-TOC or (64)Cu-1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid-octreotide ((64)Cu-TETA-OC). The tumor was imaged using (64)Cu-DOTA-TOC, (64)Cu-TETA-OC, and FDG with an animal PET scanner. (64)Cu-DOTA-TOC can be produced in amounts sufficient for clinical study with high radiochemical yield. (64)Cu-DOTA-TOC was stable in vitro, but time-dependent transchelation to protein was observed after injection into mice. In biodistribution studies, the radioactivity of (64)Cu was higher than that of (111)In in all organs except kidney. In tumor-bearing mice, (64)Cu-DOTA-TOC showed a high accumulation in the tumor, and the tumor-to-blood ratio reached as high as 8.81 +/- 1.17 at 6 h after administration. (64)Cu-DOTA-TOC showed significantly higher accumulation in the tumor than (64)Cu-TETA-OC. (64)Cu-DOTA-TOC PET showed a very clear image of the tumor, which was comparable to that of (18)F-FDG PET and very similar to that of (64)Cu

  19. Evaluation of 64Cu-labeled DOTA-D-Phe1-Tyr3-octreotide (64Cu-DOTA-TOC) for imaging somatostatin receptor-expressing tumors

    International Nuclear Information System (INIS)

    Hanaoka, Hirofumi; Tominaga, Hideyuki; Yamada, Keiich

    2009-01-01

    In-111 ( 111 In)-labeled octreotide has been clinically used for imaging somatostatin receptor-positive tumors, and radiolabeled octreotide analogs for positron emission tomography (PET) have been developed. Cu-64 ( 64 Cu; half-life, 12.7 h) is an attractive radionuclide for PET imaging and is produced with high specific activity using a small biomedical cyclotron. The aim of this study is to produce and fundamentally examine a 64 Cu-labeled octreotide analog, 64 Cu-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-D-Phe 1 -Tyr 3 -octreotide ( 64 Cu-DOTA-TOC). 64 Cu produced using a biomedical cyclotron was reacted with DOTA-TOC for 30 min at 45 deg C. The stability of 64 Cu-DOTA-TOC was evaluated in vitro (incubated with serum) and in vivo (blood collected after administration) by high performance liquid chromatography (HPLC) analysis. Biodistribution studies were performed in normal mice by administration of mixed solution of 64 Cu-DOTA-TOC and 111 In-DOTA-TOC and somatostatin receptor-positive U87MG tumor-bearing mice by administration of 64 Cu-DOTA-TOC or 64 Cu-1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetraacetic acid-octreotide ( 64 Cu-TETA-OC). The tumor was imaged using 64 Cu-DOTA-TOC, 64 Cu-TETA-OC, and fluorodeoxyglucose (FDG) with an animal PET scanner. 64 Cu-DOTA-TOC can be produced in amounts sufficient for clinical study with high radiochemical yield. 64 Cu-DOTA-TOC was stable in vitro, but time-dependent transchelation to protein was observed after injection into mice. In biodistribution studies, the radioactivity of 64 Cu was higher than that of 111 In in all organs except kidney. In tumor-bearing mice, 64 Cu-DOTA-TOC showed a high accumulation in the tumor, and the tumor-to-blood ratio reached as high as 8.81±1.17 at 6 h after administration. 64 Cu-DOTA-TOC showed significantly higher accumulation in the tumor than 64 Cu-TETA-OC. 64 Cu-DOTA-TOC PET showed a very clear image of the tumor, which was comparable to that of 18 F-FDG PET and

  20. (−) Arctigenin and (+) Pinoresinol Are Antagonists of the Human Thyroid Hormone Receptor β

    Science.gov (United States)

    2015-01-01

    Lignans are important biologically active dietary polyphenolic compounds. Consumption of foods that are rich in lignans is associated with positive health effects. Using modeling tools to probe the ligand-binding pockets of molecular receptors, we found that lignans have high docking affinity for the human thyroid hormone receptor β. Follow-up experimental results show that lignans (−) arctigenin and (+) pinoresinol are antagonists of the human thyroid hormone receptor β. The modeled complexes show key plausible interactions between the two ligands and important amino acid residues of the receptor. PMID:25383984

  1. Slow receptor dissociation kinetics differentiate macitentan from other endothelin receptor antagonists in pulmonary arterial smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    John Gatfield

    Full Text Available Two endothelin receptor antagonists (ERAs, bosentan and ambrisentan, are currently approved for the treatment of pulmonary arterial hypertension (PAH, a devastating disease involving an activated endothelin system and aberrant contraction and proliferation of pulmonary arterial smooth muscle cells (PASMC. The novel ERA macitentan has recently concluded testing in a Phase III morbidity/mortality clinical trial in PAH patients. Since the association and dissociation rates of G protein-coupled receptor antagonists can influence their pharmacological activity in vivo, we used human PASMC to characterize inhibitory potency and receptor inhibition kinetics of macitentan, ambrisentan and bosentan using calcium release and inositol-1-phosphate (IP(1 assays. In calcium release assays macitentan, ambrisentan and bosentan were highly potent ERAs with K(b values of 0.14 nM, 0.12 nM and 1.1 nM, respectively. Macitentan, but not ambrisentan and bosentan, displayed slow apparent receptor association kinetics as evidenced by increased antagonistic potency upon prolongation of antagonist pre-incubation times. In compound washout experiments, macitentan displayed a significantly lower receptor dissociation rate and longer receptor occupancy half-life (ROt(1/2 compared to bosentan and ambrisentan (ROt(1/2:17 minutes versus 70 seconds and 40 seconds, respectively. Because of its lower dissociation rate macitentan behaved as an insurmountable antagonist in calcium release and IP(1 assays, and unlike bosentan and ambrisentan it blocked endothelin receptor activation across a wide range of endothelin-1 (ET-1 concentrations. However, prolongation of the ET-1 stimulation time beyond ROt(1/2 rendered macitentan a surmountable antagonist, revealing its competitive binding mode. Bosentan and ambrisentan behaved as surmountable antagonists irrespective of the assay duration and they lacked inhibitory activity at high ET-1 concentrations. Thus, macitentan is a competitive

  2. Growth Hormone Receptor Antagonist Treatment Reduces Exercise Performance in Young Males

    DEFF Research Database (Denmark)

    Goto, K.; Doessing, S.; Nielsen, R.H.

    2009-01-01

    between the groups in terms of changes in serum free fatty acids, glycerol, (V) over dotO(2), or relative fat oxidation. Conclusion: GH might be an important determinant of exercise capacity during prolonged exercise, but GHR antagonist did not alter fat metabolism during exercise. (J Clin Endocrinol......Context: The effects of GH on exercise performance remain unclear. Objective: The aim of the study was to examine the effects of GH receptor (GHR) antagonist treatment on exercise performance. Design: Subjects were treated with the GHR antagonist pegvisomant or placebo for 16 d. After the treatment...... period, they exercised to determine exercise performance and hormonal and metabolic responses. Participants: Twenty healthy males participated in the study. Intervention: Subjects were treated with the GHR antagonist (n = 10; 10 mg/d) or placebo (n = 10). After the treatment period, they performed...

  3. Antagonistic targeting of the histamine H3 receptor decreases caloric intake in higher mammalian species.

    Science.gov (United States)

    Malmlöf, Kjell; Hastrup, Sven; Wulff, Birgitte Schellerup; Hansen, Barbara C; Peschke, Bernd; Jeppesen, Claus Bekker; Hohlweg, Rolf; Rimvall, Karin

    2007-04-15

    The main purpose of this study was to examine the effects of a selective histamine H(3) receptor antagonist, NNC 38-1202, on caloric intake in pigs and in rhesus monkeys. The compound was given intragastrically (5 or 15 mg/kg), to normal pigs (n=7) and subcutaneously (1 or 0.1mg/kg) to obese rhesus monkeys (n=9). The energy intake recorded following administration of vehicle to the same animals served as control for the effect of the compound. In addition, rhesus monkey and pig histamine H(3) receptors were cloned from hypothalamic tissues and expressed in mammalian cell lines. The in vitro antagonist potencies of NNC 38-1202 at the H(3) receptors were determined using a functional GTPgammaS binding assay. Porcine and human H(3) receptors were found to have 93.3% identity at the amino acid level and the close homology between the monkey and human H(3) receptors (98.4% identity) was confirmed. The antagonist potencies of NNC 38-1202 at the porcine, monkey and human histamine H(3) receptors were high as evidenced by K(i)-values being clearly below 20 nM, whereas the K(i)-value on the rat H(3) receptor was significantly higher (56+/-6.0 nM). NNC 38-1202, given to pigs in a dose of 15 mg/kg, produced a significant (p<0.05) reduction (55%) of calorie intake compared with vehicle alone, (132.6+/-10.0 kcal/kgday versus 59.7+/-10.2 kcal/kgday). In rhesus monkeys administration of 0.1 and 1mg/kg decreased (p<0.05) average calorie intakes by 40 and 75%, respectively. In conclusion, the present study demonstrates that antagonistic targeting of the histamine H(3) receptor decreases caloric intake in higher mammalian species.

  4. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...

  5. IMMUNOHISTOCHEMICAL DETERMINATION OF EXPRESSION OF SOMATOSTATIN RECEPTORS TYPES 1, 2A, 3 AND 5 IN NEUROENDOCRINE TUMORS OF VARIOUS LOCALIZATION AND GRADE

    Directory of Open Access Journals (Sweden)

    L. E. Gurevich

    2016-01-01

    Full Text Available Background: Prediction of clinical benefits of somatostatin analogues in patients with neuroendocrine tumors (NET is very important prior to their administration. Data on immunohistochemical assessment of the expression of somatostatin receptors (SSR of various types, obtained from large samples of NET with various localization, functional activity and degree of malignancy, are scarce; therefore, the study was aimed at assessment of the latter.Materials and methods: We performed an immunohistochemical study with antibodies to SSR1, 2A, 3 and 5  types on tissue samples obtained during diagnostic and intra-operative biopsies from 399 NETs: 168 from pancreas, 120 from gastrointestinal tract (stomach, 48, from small intestine, 39, 14 of which being from duodenum; appendix, 6, colon and the rectum, 15 and 12, respectively, 84 from lung, 6 from thymus/mediastinum, and 21 from NET metastases of unknown primary localization.Results: Very high levels expression of receptors SSR2A preferentially binding to somatostatin analogues, which are currently used in clinical practice, were detected in the small intestine NETs (22/25, 88%, appendix (5/6, 83.3%, colon (10/15, 66.7%, thymus (4/6, 66.7%, atypical carcinoids of the lung (10/15, 66.7%, stomach (27/41, 65.8% and pancreas (105/165, 63.6%. The lowest expression was found in rectal NETs (5/12, 41.7% and small and large cell neuroendocrine lung carcinomas (20, 11.1%. Among functioning NETs, the highest level of SSR2A was found in gastrinomas (18/19, 94.7%, glucagonomas (15/16, 93.8%, small intestine carcinoids (31/35, 88.6%, and somatostatinomas (2/3, 66.7%. The lowest expression was detected in ACTH secreting tumors with Cushing's syndrome (11/12, 50%, and in insulinomas (34/69, 49.3%. SSR2A expression in functionally inactive pancreatic NETs was significantly higher than in insulinomas (57/82, 34/69 vs 69.5 and 49.3%, respectively. SSR2A expression was associated with the degree of malignancy and is

  6. Guideline for PET/CT imaging of neuroendocrine neoplasms with {sup 68}Ga-DOTA-conjugated somatostatin receptor targeting peptides and {sup 18}F-DOPA

    Energy Technology Data Exchange (ETDEWEB)

    Bozkurt, Murat Fani [Hacettepe University Faculty of Medicine Department of Nuclear Medicine, Ankara (Turkey); Virgolini, Irene; Decristoforo, Clemens [Medical University Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Balogova, Sona [Comenius University and St. Elisabeth Oncology Institute, Department of Nuclear Medicine, Bratislava (Slovakia); Tenon Hospital AP-HP and Universite Pierre et Marie Curie, Department of Nuclear Medicine, Paris (France); Beheshti, Mohsen [St. Vincent' s Hospital, PET-CT Center, Department of Nuclear Medicine and Endocrinology, Linz (Austria); Paracelsus Medical University, Department of Nuclear Medicine, Salzburg (Austria); Rubello, Domenico [Santa Maria della Misericordia Hospital, Department of Nuclear Medicine, PET Center and Medical Physics and Radiology, Rovigo (Italy); Ambrosini, Valentina; Fanti, Stefano [University of Bologna, Department of Experimental, Diagnostic and Specialty Medicine-DIMES, Bologna (Italy); Kjaer, Andreas [National University Hospital and University of Copenhagen, Department of Clinical Physiology, Nuclear Medicine and PET, Rigshospitalet, Copenhagen (Denmark); Delgado-Bolton, Roberto [San Pedro Hospital and Centre for Biomedical Research of La Rioja (CIBIR), Department of Diagnostic Imaging (Radiology) and Nuclear Medicine, Logrono (Spain); Kunikowska, Jolanta [Medical University of Warsaw, Nuclear Medicine, Warsaw (Poland); Oyen, Wim J.G. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, London (United Kingdom); Chiti, Arturo [Humanitas University, Nuclear Medicine Department, Rozzano, MI (Italy); Giammarile, Francesco [University of Lyon, Nuclear Medicine, Lyon (France)

    2017-08-15

    Neuroendocrine neoplasms are a heterogenous group of tumours, for which nuclear medicine plays an important role in the diagnostic work-up as well as in the targeted therapeutic options. This guideline is aimed to assist nuclear medicine physicians in recommending, performing, reporting and interpreting the results of somatostatin receptor (SSTR) PET/CT imaging using {sup 68}Ga-DOTA-conjugated peptides, as well as {sup 18}F-DOPA imaging for various neuroendocrine neoplasms. The previous procedural guideline by EANM regarding the use PET/CT tumour imaging with {sup 68}Ga-conjugated peptides has been revised and updated with the relevant and recent literature in the field with contribution of distinguished experts. (orig.)

  7. Studies in rats on octreotide labelled with Ga-67: A potential radiopharmaceutical agent for the treatment of somatostatin receptor-positive tumours

    International Nuclear Information System (INIS)

    Lazniekova, A.; Laznieek, M.; Trejtnar, F.; Maecke, H.R.

    2001-01-01

    The paper presents the preparation, biodistribution and analysis of elimination mechanisms of 67 Ga-[DFO]-octreotide in rats. For labelling of the ligand with 67 Ga, desferrioxamine B (DFO) coupled to octreotide via the succinyl linker has been shown to form a stable chelating agent for binding of 67 Ga. The radiopharmaceutical was prepared by direct chelating of 67 Ga 3+ with [DFO]-octreotide in a slightly acidic reaction medium with high radiochemical purity. Pharmacokinetics of 67 Ga-[DFO]-octreotide of radioactivity in rats has shown relatively rapid elimination of the compound from the body with a long-term retention in the kidney and organs with high somatostatin receptor density. The agent was eliminated mostly by urine predominantly by the mechanism of glomerular filtration. (author)

  8. Preclinical evaluation of [99mTc/EDDA/tricine/HYNIC0, 1-Nal3, Thr8]-octreotide as a new analogue in the detection of somatostatin-receptor-positive tumors.

    Science.gov (United States)

    Gandomkar, Mostafa; Najafi, Reza; Shafiei, Mohammad; Mazidi, Mohammad; Ebrahimi, Sayed Esmaeil Sadat

    2007-08-01

    Radiolabeled somatostatin analogues are important tools for the in vivo localization and targeted radionuclide therapy of somatostatin-receptor-positive tumors. The aim of this study was to evaluate a new somatostatin analogue designed for the labeling with (99m)Tc: [6-hydrazinopyridine-3-carboxylic acid (HYNIC(0)), 1-Nal(3), Thr(8)]-octreotide ([HYNIC]-NATE), using ethylenediamine-N,N'-diacetic acid (EDDA) and tricine as coligands. Synthesis was preformed on a solid phase using a standard Fmoc strategy. Labeling with (99m)Tc was performed at 100 degrees C for 10 min using SnCl(2) as a reductant. Radiochemical analysis involved ITLC and high-performance liquid chromatography methods. Peptide conjugate affinity was determined in AR4-2J cell membranes. The internalization and externalization rates were studied in sstr(2)-expressing AR4-2J cells. Biodistribution of radiopeptide was studied in rats bearing the AR4-2J tumor. Radiolabeling was performed at high specific activities, and radiochemical purity was >95%. Peptide conjugate showed high affinity binding for sstr(2). The radioligand showed a moderate and specific internalization into AR4-2J cells (14.13+/-0.61% at 4 h). In animal biodistribution studies, a receptor-specific uptake of radioactivity was observed in somatostatin-receptor-positive organs. After 4 h, uptake in the AR4-2J tumor was 1.33+/-0.23%ID/g (percentage of injected dose per gram of tissue). These data show that [(99m)Tc/EDDA/tricine/HYNIC]-NATE is a specific radioligand for the somatostatin-receptor-positive tumors and is a suitable candidate for clinical studies.

  9. Preclinical evaluation of [99mTc/EDDA/tricine/HYNIC0, 1-Nal3, Thr8]-octreotide as a new analogue in the detection of somatostatin-receptor-positive tumors

    International Nuclear Information System (INIS)

    Gandomkar, Mostafa; Najafi, Reza; Shafiei, Mohammad; Mazidi, Mohammad; Ebrahimi, Sayed Esmaeil Sadat

    2007-01-01

    Purpose: Radiolabeled somatostatin analogues are important tools for the in vivo localization and targeted radionuclide therapy of somatostatin-receptor-positive tumors. The aim of this study was to evaluate a new somatostatin analogue designed for the labeling with 99m Tc: [6-hydrazinopyridine-3-carboxylic acid (HYNIC 0 ), 1-Nal 3 , Thr 8 ]-octreotide ([HYNIC]-NATE), using ethylenediamine-N,N'-diacetic acid (EDDA) and tricine as coligands. Methods: Synthesis was preformed on a solid phase using a standard Fmoc strategy. Labeling with 99m Tc was performed at 100 o C for 10 min using SnCl 2 as a reductant. Radiochemical analysis involved ITLC and high-performance liquid chromatography methods. Peptide conjugate affinity was determined in AR4-2J cell membranes. The internalization and externalization rates were studied in sstr 2 -expressing AR4-2J cells. Biodistribution of radiopeptide was studied in rats bearing the AR4-2J tumor. Results: Radiolabeling was performed at high specific activities, and radiochemical purity was >95%. Peptide conjugate showed high affinity binding for sstr 2 . The radioligand showed a moderate and specific internalization into AR4-2J cells (14.13±0.61% at 4 h). In animal biodistribution studies, a receptor-specific uptake of radioactivity was observed in somatostatin-receptor-positive organs. After 4 h, uptake in the AR4-2J tumor was 1.33±0.23%ID/g (percentage of injected dose per gram of tissue). Conclusion: These data show that [ 99m Tc/EDDA/tricine/HYNIC]-NATE is a specific radioligand for the somatostatin-receptor-positive tumors and is a suitable candidate for clinical studies

  10. Preliminary Molecular Dynamic Simulations of the Estrogen Receptor Alpha Ligand Binding Domain from Antagonist to Apo

    Directory of Open Access Journals (Sweden)

    Adrian E. Roitberg

    2008-06-01

    Full Text Available Estrogen receptors (ER are known as nuclear receptors. They exist in the cytoplasm of human cells and serves as a DNA binding transcription factor that regulates gene expression. However the estrogen receptor also has additional functions independent of DNA binding. The human estrogen receptor comes in two forms, alpha and beta. This work focuses on the alpha form of the estrogen receptor. The ERα is found in breast cancer cells, ovarian stroma cells, endometrium, and the hypothalamus. It has been suggested that exposure to DDE, a metabolite of DDT, and other pesticides causes conformational changes in the estrogen receptor. Before examining these factors, this work examines the protein unfolding from the antagonist form found in the 3ERT PDB crystal structure. The 3ERT PDB crystal structure has the estrogen receptor bound to the cancer drug 4-hydroxytamoxifen. The 4-hydroxytamoxifen ligand was extracted before the simulation, resulting in new conformational freedom due to absence of van der Waals contacts between the ligand and the receptor. The conformational changes that result expose the binding clef of the co peptide beside Helix 12 of the receptor forming an apo conformation. Two key conformations in the loops at either end of the H12 are produced resulting in the antagonist to apo conformation transformation. The results were produced over a 42ns Molecular Dynamics simulation using the AMBER FF99SB force field.

  11. Effects of combining opioids and clinically available NMDA receptor antagonists in the treatment of pain.

    NARCIS (Netherlands)

    Snijdelaar, D.G.

    2005-01-01

    This thesis concerns the effects of combining opioids with clinically available NMDA receptor antagonists in the treatment of acute and chronic pain. There are a number of problems with the use of opioids, such as, the development of tolerance/hyperalgesia, the reduced effectiveness in (central)

  12. Tying up Nicotine: New Selective Competitive Antagonist of the Neuronal Nicotinic Acetylcholine Receptors

    DEFF Research Database (Denmark)

    Petersen, Ida Nymann; Crestey, François; Jensen, Anders A

    2015-01-01

    Conformational restriction of the pyrrolidine nitrogen in nicotine by the introduction of an ethylene bridge provided a potent and selective antagonist of the α4β2-subtype of the nicotinic acetylcholine receptors. Resolution by chiral SFC, pharmacological characterization of the two enantiomers...

  13. Synthesis and pharmacological evaluation of DHβE analogs as neuronal nicotinic acetylcholine receptor antagonists

    DEFF Research Database (Denmark)

    Jepsen, Tue H.; Jensen, Anders A.; Lund, Mads Henrik

    2014-01-01

    Dihydro-β-erythroidine (DHβE) is a member of the Erythrina family of alkaloids and a potent competitive antagonist of the α4β2-subtype of the nicotinic acetylcholine receptors (nAChRs). Guided by an X-ray structure of DHβE in complex with an ACh binding protein, we detail the design, synthesis...

  14. Effect of the calcitonin gene-related peptide (CGRP) receptor antagonist telcagepant in human cranial arteries

    NARCIS (Netherlands)

    L. Edvinsson (Lars); K.Y. Chan (Kayi); S. Eftekhari; E. Nilsson (Elisabeth); R. de Vries (René); H. Säveland (Hans); C.M.F. Dirven (Clemens); A.H.J. Danser (Jan)

    2010-01-01

    textabstractIntroduction: Calcitonin gene-related peptide (CGRP) is a neuronal messenger in intracranial sensory nerves and is considered to play a significant role in migraine pathophysiology. Materials and methods: We investigated the effect of the CGRP receptor antagonist, telcagepant, on

  15. Interaction between Ca++-channel antagonists and α2-adrenergic receptors in rabbit ileal cell membrane

    International Nuclear Information System (INIS)

    Homeidan, F.R.; Wicks, J.; Cusolito, S.; El-Sabban, M.E.; Sharp, G.W.G.; Donowitz, M.

    1986-01-01

    An interaction between Ca ++ -channel antagonists and the α 2 -adrenergic receptor on active electrolyte transport was demonstrated in rabbit ileum. Clonidine, an α 2 -agonist, stimulated NaCl absorption apparently by Ca ++ -channel antagonism since it inhibited 45 Ca ++ uptake across the basolateral membrane and decreased total ileal calcium content. This stimulation was inhibited by the Ca ++ -channel antagonists dl- and l-verapamil and cadmium but not by nifedipine. The binding of 3 H-yohimbine, a specific α 2 -adrenergic antagonist, was studied on purified ileal cell membranes using a rapid filtration technique. dl-Verapamil and Cd ++ inhibited the specific binding of 3 H-yohimbine over the same concentration range in which they affected transport. In contrast, nifedipine had no effect on binding, just as it had no effect on clonidine-stimulated NaCl absorption. These data demonstrate that there is an interaction between Ca ++ -channels and α 2 -adrenergic receptors in ileal basolateral membranes. Some Ca ++ -channel antagonists alter α 2 -adrenergic binding to the receptor and α 2 -agonist binding leads to changes in Ca ++ entry. A close spatial relationship between the Ca ++ -channel and the α 2 -receptor could explain the data

  16. Bicyclams, selective antagonists of the human chemokine receptor CXCR4, potently inhibit feline immunodeficiency virus replication

    NARCIS (Netherlands)

    Horzinek, M.C.; Egberink, H.F.; Clercq, E. de; Vliet, A.L.W. van; Balzarini, J.; Bridger, G.J.; Henson, G.; Schols, D.

    1999-01-01

    Bicyclams are low-molecular-weight anti-human immunodeficiency virus (HIV) agents that have been shown to act as potent and selective CXC chemokine receptor 4 (CXCR4) antagonists. Here, we demonstrate that bicyclams are potent inhibitors of feline immunodeficiency virus (FIV) replication when

  17. A Time-course Study with the Androgen Receptor Antagonist Flutamide in Fish

    Science.gov (United States)

    Flutamide, a drug registered to treat some types of prostate cancer in humans, has been used for many years as a model androgen receptor (AR) antagonist in studies aimed at characterizing disruption of the vertebrate hypothalamic-pituitary-gonadal (HPG) axis. Various studies hav...

  18. N-Oxide analogs of WAY-100635 : new high affinity 5-HT (1A) receptor antagonists

    NARCIS (Netherlands)

    Oberwinkler - Marchais, Sandrine; Nowicki, B; Pike, VW; Halldin, C; Sandell, J; Chou, YH; Gulyas, B; Brennum, LT; Farde, L; Wikstrom, H V

    2005-01-01

    WAY-100635 [N-(2-(1-(4-(2-methoxyphenyl)piperazinyl)ethyl))-N-(2-pyridinyl)cyclohexanecarboxamide] 1 and its O-des-methyl derivative DWAY 2 are well-known high affinity 5-HT1A receptor antagonists. which when labeled with carbon-II (beta(+): t(1/2) 20.4min) in the carbonyl group are effective

  19. Cortical epileptic afterdischarges in immature rats are differently influenced by NMDA receptor antagonists

    Czech Academy of Sciences Publication Activity Database

    Šlamberová, Romana; Mareš, Pavel

    2005-01-01

    Roč. 516, č. 1 (2005), s. 10-17 ISSN 0014-2999 R&D Projects: GA MŠk(CZ) LN00B122 Institutional research plan: CEZ:AV0Z5011922 Keywords : epileptic seizure * cerebral cortex * NMDA receptor antagonist Subject RIV: FH - Neuro logy Impact factor: 2.477, year: 2005

  20. Attenuation of antagonist-induced impairment of dopamine receptors by L-prolyl-L-leucyl-glycinamide

    International Nuclear Information System (INIS)

    Saleh, M.I.M.

    1988-01-01

    The present study was undertaken in order to determine whether chronic,long-term postnatal challenge of rat pups per se, with specific dopamine D1 and D2 receptor antagonists, would modify the ontogeny of the respective receptor types. Since the neuropeptide L-prolyl-L-leucyl-glycinamide (PLG) attenuates the effect of haloperidol on dopamine D2 receptors in adult rats it was of interest to determine whether PLG would modulate antagonists-induced alterations in the ontogeny of striatal dopamine D1 and D2 receptors. Half of the rats were treated daily for 32 days from birth with SCH-23390, a selective dopamine D1 antagonist; or spiroperidol, a selective dopamine D2 antagonists; or both SCH-23390 and spiroperidol; or saline. The other half of the litters were treated with PLG, in combination with the other treatments. Animals were decapitated at 5, 8, and 12 weeks from birth for neurochemical analysis of the striatum. Chronic SCH-23390 treatment produced a 70-80% decrease in the binding of [ 3 H] SCH-23390 to striatal homogenates. The alteration at 5 weeks was associated with a 78% decrease in the Bmax for [ 3 H] SCH-23390 binding, and no change in the K D . Similarly, at 5, 8, and 12 weeks, chronic spiroperidol treatment reduced the binding of [ 3 H] spiroperidol to striatal homogenates by 70-80%

  1. Discovery and mapping of an intracellular antagonist binding site at the chemokine receptor CCR2

    DEFF Research Database (Denmark)

    Zweemer, Annelien J M; Bunnik, Julia; Veenhuizen, Margo

    2014-01-01

    be divided into two groups with most likely two topographically distinct binding sites. The aim of the current study was to identify the binding site of one such group of ligands, exemplified by three allosteric antagonists, CCR2-RA-[R], JNJ-27141491, and SD-24. We first used a chimeric CCR2/CCR5 receptor...

  2. I. Effects of a Dopamine Receptor Antagonist on Fathead Minnow, Pimephales promelas ,Reproduction

    Science.gov (United States)

    This study used a 21 d fathead minnow (Pimephales promelas) reproduction assay to test the hypothesis that exposure to the dopamine 2 receptor (D2R) antagonist, haloperidol, would impair fish reproduction. Additionally, a 96 h experiment with fathead minnows and zebrafish (Danio ...

  3. CHOLECYSTOKININ RECEPTOR ANTAGONIST HALTS PROGRESSION OF PANCREATIC CANCER PRECURSOR LESIONS AND FIBROSIS IN MICE

    Science.gov (United States)

    Smith, Jill P.; Cooper, Timothy K.; McGovern, Christopher O.; Gilius, Evan L.; Zhong, Qing; Liao, Jiangang; Molinolo, Alfredo A.; Gutkind, J. Silvio; Matters, Gail L.

    2014-01-01

    Objectives Exogenous administration of cholecystokinin (CCK) induces hypertrophy and hyperplasia of the pancreas with an increase in DNA content. We hypothesized that endogenous CCK is involved with the malignant progression of pancreatic intraepithelial neoplasia (PanIN) lesions and the fibrosis associated with pancreatic cancer. Methods The presence of CCK receptors in early PanIN lesions was examined by immunohistochemistry in mouse and human pancreas. Pdx1-Cre/LSL-KrasG12D transgenic mice were randomized to receive either untreated drinking water or water supplemented with a CCK-receptor antagonist (proglumide, 0.1mg/ml). Pancreas from mice were removed and examined histologically for number and grade of PanINs after 1, 2 or 4 months of antagonist therapy. Results Both CCK-A and CCK-B receptors were identified in early stage PanINs from mouse and human pancreas. The grade of PanIN lesions was reversed and progression to advanced lesions arrested in mice treated with proglumide compared to controls (p=0.004). Furthermore, pancreatic fibrosis was significantly reduced in antagonist-treated animals compared to vehicle (pitalic>0.001). Conclusions These findings demonstrate that endogenous CCK is in part responsible for the development and progression of pancreatic cancer. Use of CCK-receptor antagonists may have a role in cancer prophylaxis in high risk subjects, and may reduce fibrosis in the microenvironment. PMID:25058882

  4. Effects of a histamine H4 receptor antagonist on cisplatin-induced anorexia in mice.

    Science.gov (United States)

    Yamamoto, Kouichi; Okui, Rikuya; Yamatodani, Atsushi

    2018-04-12

    Cancer chemotherapy often induces gastrointestinal symptoms such as anorexia, nausea, and vomiting. Antiemetic agents are effective in inhibiting nausea and vomiting, but patients still experience anorexia. We previously reported that chemotherapeutic agent-induced anorexia is associated with an increase of inflammatory cytokines. Other studies also reported that antagonism of the histamine H 4 receptor is anti-inflammatory. In this study, we investigated the involvement of the H 4 receptor in the development of chemotherapy-induced anorexia in mice. Cisplatin-induced anorexia occurred within 24 h of its administration and continued for 3 days. The early phase (day 1), but not the delayed phase (days 2 and 3), of anorexia was inhibited by the daily injection of a 5-HT 3 receptor antagonist (granisetron). However, a corticosteroid (dexamethasone) or selective H 4 receptor antagonist (JNJ7777120) abolished the delayed phases of anorexia. Cisplatin significantly increased TNF-α mRNA expression in the hypothalamus and spleen, and the period of expression increase paralleled the onset period of anorexia. In addition, pretreatment with JNJ7777120 completely inhibited the increased expression. These results suggest that TNF-α mRNA expression via H 4 receptors may contribute to the development of cisplatin-induced anorexia, and that H 4 receptor antagonists are potentially useful treatments. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Structural Insights into Selective Ligand-Receptor Interactions Leading to Receptor Inactivation Utilizing Selective Melanocortin 3 Receptor Antagonists.

    Science.gov (United States)

    Cai, Minying; Marelli, Udaya Kiran; Mertz, Blake; Beck, Johannes G; Opperer, Florian; Rechenmacher, Florian; Kessler, Horst; Hruby, Victor J

    2017-08-15

    Systematic N-methylated derivatives of the melanocortin receptor ligand, SHU9119, lead to multiple binding and functional selectivity toward melanocortin receptors. However, the relationship between N-methylation-induced conformational changes in the peptide backbone and side chains and melanocortin receptor selectivity is still unknown. We conducted comprehensive conformational studies in solution of two selective antagonists of the third isoform of the melanocortin receptor (hMC3R), namely, Ac-Nle-c[Asp-NMe-His 6 -d-Nal(2') 7 -NMe-Arg 8 -Trp 9 -Lys]-NH 2 (15) and Ac-Nle-c[Asp-His 6 -d-Nal(2') 7 -NMe-Arg 8 -NMe-Trp 9 -NMe-Lys]-NH 2 (17). It is known that the pharmacophore (His 6 -DNal 7 -Arg 8 -Trp 9 ) of the SHU-9119 peptides occupies a β II-turn-like region with the turn centered about DNal 7 -Arg 8 . The analogues with hMC3R selectivity showed distinct differences in the spatial arrangement of the Trp 9 side chains. In addition to our NMR studies, we also carried out molecular-level interaction studies of these two peptides at the homology model of hMC3R. Earlier chimeric human melanocortin 3 receptor studies revealed insights regarding the binding and functional sites of hMC3R selectivity. Upon docking of peptides 15 and 17 to the binding pocket of hMC3R, it was revealed that Arg 8 and Trp 9 side chains are involved in a majority of the interactions with the receptor. While Arg 8 forms polar contacts with D154 and D158 of hMC3R, Trp 9 utilizes π-π stacking interactions with F295 and F298, located on the transmembrane domain of hMC3R. It is hypothesized that as the frequency of Trp 9 -hMC3R interactions decrease, antagonistic activity increases. The absence of any interactions of the N-methyl groups with hMC3R suggests that their primary function is to modulate backbone conformations of the ligands.

  6. Aldosterone and aldosterone receptor antagonists in patients with chronic heart failure

    Directory of Open Access Journals (Sweden)

    Nappi J

    2011-06-01

    Full Text Available Jean M Nappi, Adam SiegClinical Pharmacy and Outcome Sciences, South Carolina College of Pharmacy, Medical University of South Carolina Campus, Charleston, SC, USAAbstract: Aldosterone is a mineralocorticoid hormone synthesized by the adrenal glands that has several regulatory functions to help the body maintain normal volume status and electrolyte balance. Studies have shown significantly higher levels of aldosterone secretion in patients with congestive heart failure compared with normal patients. Elevated levels of aldosterone have been shown to elevate blood pressure, cause left ventricular hypertrophy, and promote cardiac fibrosis. An appreciation of the true role of aldosterone in patients with chronic heart failure did not become apparent until the publication of the Randomized Aldactone Evaluation Study. Until recently, the use of aldosterone receptor antagonists has been limited to patients with severe heart failure and patients with heart failure following myocardial infarction. The Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF study added additional evidence to support the expanded use of aldosterone receptor antagonists in heart failure patients. The results of the EMPHASIS-HF trial showed that patients with mild-to-moderate (New York Heart Association Class II heart failure had reductions in mortality and hospitalizations from the addition of eplerenone to optimal medical therapy. Evidence remains elusive about the exact mechanism by which aldosterone receptor antagonists improve heart failure morbidity and mortality. The benefits of aldosterone receptor antagonist use in heart failure must be weighed against the potential risk of complications, ie, hyperkalemia and, in the case of spironolactone, possible endocrine abnormalities, in particular gynecomastia. With appropriate monitoring, these risks can be minimized. We now have evidence that patients with mild-to-severe symptoms

  7. NMDA receptor antagonist ketamine impairs feature integration in visual perception

    NARCIS (Netherlands)

    Meuwese, Julia D I; van Loon, Anouk M; Scholte, H Steven; Lirk, Philipp B; Vulink, Nienke C C; Hollmann, Markus W; Lamme, Victor A F

    2013-01-01

    Recurrent interactions between neurons in the visual cortex are crucial for the integration of image elements into coherent objects, such as in figure-ground segregation of textured images. Blocking N-methyl-D-aspartate (NMDA) receptors in monkeys can abolish neural signals related to figure-ground

  8. 5-HT6 receptor antagonist attenuates the memory deficits associated with neuropathic pain and improves the efficacy of gabapentinoids.

    Science.gov (United States)

    Jayarajan, Pradeep; Nirogi, Ramakrishna; Shinde, Anil; Goura, Venkatesh; Babu, Vuyyuru Arun; Yathavakilla, Sumanth; Bhyrapuneni, Gopinadh

    2015-10-01

    Memory deficit is a co-morbid disorder in patients suffering from neuropathic pain. Gabapentin and pregabalin (gabapentinoids) are among the widely prescribed medications for the treatment of neuropathic pain. Memory loss and sedation are the commonly reported side effects with gabapentinoids. Improving the cognitive functions and attenuating drug-induced side effects may play a crucial role in the management of pain. We evaluated the effects of 5-HT6 receptor antagonists on the memory deficits associated with neuropathy. We also studied the effects of 5-HT6 receptor antagonists on the side effects, and the analgesic effects of gabapentinoids. 5-HT6 receptor antagonists attenuated the cognitive deficits in neuropathic rats. Neuropathic rats co-treated with 5-HT6 receptor antagonist and gabapentinoids showed improvement in memory. 5-HT6 receptor antagonists enhanced the analgesic effects of gabapentinoids but had no effect on the motor side effects. The observed effects may not be due to pharmacokinetic interactions. 5-HT6 receptor antagonist attenuate the cognitive deficits associated with neuropathy, and this effect is also seen when co-treated with gabapentinoids. Since, 5-HT6 antagonists improved the effectiveness of gabapentinoids, reduction in the dosage and frequency of gabapentinoids treatment may reduce the side effects. Combining 5-HT6 receptor antagonist with gabapentinoids may offer a novel treatment strategy for neuropathic pain. Copyright © 2015 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  9. Mutational analysis of the antagonist-binding site of the histamine H(1) receptor.

    Science.gov (United States)

    Wieland, K; Laak, A M; Smit, M J; Kühne, R; Timmerman, H; Leurs, R

    1999-10-15

    We combined in a previously derived three-dimensional model of the histamine H(1) receptor (Ter Laak, A. M., Timmerman, H., Leurs, H., Nederkoorn, P. H. J., Smit, M. J., and Donne-Op den Kelder, G. M. (1995) J. Comp. Aid. Mol. Design. 9, 319-330) a pharmacophore for the H(1) antagonist binding site (Ter Laak, A. M., Venhorst, J., Timmerman, H., and Donné-Op de Kelder, G. M. (1994) J. Med. Chem. 38, 3351-3360) with the known interacting amino acid residue Asp(116) (in transmembrane domain III) of the H(1) receptor and verified the predicted receptor-ligand interactions by site-directed mutagenesis. This resulted in the identification of the aromatic amino acids Trp(167), Phe(433), and Phe(436) in transmembrane domains IV and VI of the H(1) receptor as probable interaction points for the trans-aromatic ring of the H(1) antagonists. Subsequently, a specific interaction of carboxylate moieties of two therapeutically important, zwitterionic H(1) antagonists with Lys(200) in transmembrane domain V was predicted. A Lys(200) --> Ala mutation results in a 50- (acrivastine) to 8-fold (d-cetirizine) loss of affinity of these zwitterionic antagonists. In contrast, the affinities of structural analogs of acrivastine and cetirizine lacking the carboxylate group, triprolidine and meclozine, respectively, are unaffected by the Lys(200) --> Ala mutation. These data strongly suggest that Lys(200), unique for the H(1) receptor, acts as a specific anchor point for these "second generation" H(1) antagonists.

  10. The pharmacological rationale for combining muscarinic receptor antagonists and beta-adrenoceptor agonists in the treatment of airway and bladder disease

    NARCIS (Netherlands)

    Dale, Philippa R.; Cernecka, Hana; Schmidt, Martina; Dowling, Mark R.; Charlton, Steven J.; Pieper, Michael P.; Michel, Martin C.

    Muscarinic receptor antagonists and beta-adrenoceptor agonists are used in the treatment of obstructive airway disease and overactive bladder syndrome. Here we review the pharmacological rationale for their combination. Muscarinic receptors and beta-adrenoceptors are physiological antagonists for

  11. Inhibition of Ebola and Marburg Virus Entry by G Protein-Coupled Receptor Antagonists.

    Science.gov (United States)

    Cheng, Han; Lear-Rooney, Calli M; Johansen, Lisa; Varhegyi, Elizabeth; Chen, Zheng W; Olinger, Gene G; Rong, Lijun

    2015-10-01

    Filoviruses, consisting of Ebola virus (EBOV) and Marburg virus (MARV), are among the most lethal infectious threats to mankind. Infections by these viruses can cause severe hemorrhagic fevers in humans and nonhuman primates with high mortality rates. Since there is currently no vaccine or antiviral therapy approved for humans, there is an urgent need to develop prophylactic and therapeutic options for use during filoviral outbreaks and bioterrorist attacks. One of the ideal targets against filoviral infection and diseases is at the entry step, which is mediated by the filoviral glycoprotein (GP). In this report, we screened a chemical library of small molecules and identified numerous inhibitors, which are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs, including histamine receptors, 5-HT (serotonin) receptors, muscarinic acetylcholine receptor, and adrenergic receptor. These inhibitors can effectively block replication of both infectious EBOV and MARV, indicating a broad antiviral activity of the GPCR antagonists. The time-of-addition experiment and microscopic studies suggest that GPCR antagonists block filoviral entry at a step following the initial attachment but prior to viral/cell membrane fusion. These results strongly suggest that GPCRs play a critical role in filoviral entry and GPCR antagonists can be developed as an effective anti-EBOV/MARV therapy. Infection of Ebola virus and Marburg virus can cause severe illness in humans with a high mortality rate, and currently there is no FDA-approved vaccine or therapeutic treatment available. The 2013-2015 epidemic in West Africa underscores a lack of our understanding in the infection and pathogenesis of these viruses and the urgency of drug discovery and development. In this study, we have identified numerous inhibitors that are known G protein-coupled receptor (GPCR) antagonists targeting different GPCRs. These inhibitors can effectively block replication of both infectious

  12. Enantiopure Indolo[2,3-a]quinolizidines: Synthesis and Evaluation as NMDA Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Nuno A. L. Pereira

    2016-08-01

    Full Text Available Enantiopure tryptophanol is easily obtained from the reduction of its parent natural amino acid trypthophan (available from the chiral pool, and can be used as chiral auxiliary/inductor to control the stereochemical course of a diastereoselective reaction. Furthermore, enantiopure tryptophanol is useful for the syntheses of natural products or biological active molecules containing the aminoalcohol functionality. In this communication, we report the development of a small library of indolo[2,3-a]quinolizidines and evaluation of their activity as N-Methyl d-Aspartate (NMDA receptor antagonists. The indolo[2,3-a]quinolizidine scaffold was obtained using the following key steps: (i a stereoselective cyclocondensation of (S- or (R-tryptophanol with appropriate racemic δ-oxoesters; (ii a stereocontrolled cyclization on the indole nucleus. The synthesized enantiopure indolo[2,3-a]quinolizidines were evaluated as NMDA receptor antagonists and one compound was identified to be 2.9-fold more potent as NMDA receptor blocker than amantadine (used in the clinic for Parkinson’s disease. This compound represents a hit compound for the development of novel NMDA receptor antagonists with potential applications in neurodegenerative disorders associated with overactivation of NMDA receptors.

  13. Assembly of high-affinity insulin receptor agonists and antagonists from peptide building blocks

    Science.gov (United States)

    Schäffer, Lauge; Brissette, Renee E.; Spetzler, Jane C.; Pillutla, Renuka C.; Østergaard, Søren; Lennick, Michael; Brandt, Jakob; Fletcher, Paul W.; Danielsen, Gillian M.; Hsiao, Ku-Chuan; Andersen, Asser S.; Dedova, Olga; Ribel, Ulla; Hoeg-Jensen, Thomas; Hansen, Per Hertz; Blume, Arthur J.; Markussen, Jan; Goldstein, Neil I.

    2003-01-01

    Insulin is thought to elicit its effects by crosslinking the two extracellular α-subunits of its receptor, thereby inducing a conformational change in the receptor, which activates the intracellular tyrosine kinase signaling cascade. Previously we identified a series of peptides binding to two discrete hotspots on the insulin receptor. Here we show that covalent linkage of such peptides into homodimers or heterodimers results in insulin agonists or antagonists, depending on how the peptides are linked. An optimized agonist has been shown, both in vitro and in vivo, to have a potency close to that of insulin itself. The ability to construct such peptide derivatives may offer a path for developing agonists or antagonists for treatment of a wide variety of diseases. PMID:12684539

  14. Cysteamine induces cholecystokinin release from the duodenum. Evidence for somatostatin as an inhibitory paracrine regulator of cholecystokinin secretion in the rat

    International Nuclear Information System (INIS)

    Abucham, J.; Reichlin, S.

    1990-01-01

    To determine whether cholecystokinin secretion is regulated by endogenous somatostatin, somatostatin deficiency was induced in vivo with cysteamine (250 mg/kg body wt, IV) or anti-somatostatin antiserum in anaesthetized rats and in vitro with cysteamine (30 micrograms/mL) in a rat duodenum-incubation system. Cholecystokinin secretion was assessed in vivo by measuring amylase in duodenal perfusates collected at 10-minute intervals for 1 hour and in vitro by a carboxy-terminal radioimmunoassay. Cysteamine induced a marked decrease in duodenal immunoreactive somatostatin both in vivo (50%) and in vitro (60%). The rate of amylase secretion increased from 9.7 +/- 2.1 U (mean +/- SE) to 28.0 +/- 4.8 U at 20 minutes (P less than 0.001). The cholecystokinin-receptor antagonist CR-1392 abolished amylase response for 30 minutes, whereas the more potent antagonists Asperlicin (18.0 mg/kg body wt, IV) and L-364,718 (0.25 mg/kg body wt, IV) caused prolonged blockade. The rate of amylase secretion in gastrectomized animals increased from 7.2 +/- 2.0 U to 15.0 +/- 2.2 U 20 minutes after cysteamine administration (P less than 0.01), indicating that the effect was not due to the presence of gastrin. In vitro, cysteamine caused a nearly fourfold increase in cholecystokinin secretion compared with controls (63.1 +/- 4.9 vs. 15.2 +/- 3.7, respectively; P less than 0.001). In vivo immunoneutralization of circulating somatostatin with a high-affinity and high-capacity antiserum produced no significant change in the rate of amylase secretion. These results suggest that cholecystokinin secretion is tonically inhibited by somatostatin and that this effect is mediated by locally secreted (paracrine) but not by circulating somatostatin

  15. Thyroid Hormone Receptor Antagonists: From Environmental Pollution to Novel Small Molecules.

    Science.gov (United States)

    Mackenzie, Louise S

    2018-01-01

    Thyroid hormone receptors (TRs) are nuclear receptors which control transcription, and thereby have effects in all cells within the body. TRs are an important regulator in many basic physiological processes including development, growth, metabolism, and cardiac function. The hyperthyroid condition results from an over production of thyroid hormones resulting in a continual stimulation of thyroid receptors which is detrimental for the patient. Therapies for hyperthyroidism are available, but there is a need for new small molecules that act as TR antagonists to treat hyperthyroidism. Many compounds exhibit TR antagonism and are considered detrimental to health. Some drugs in the clinic (most importantly, amiodarone) and environmental pollution exhibit TR antagonist properties and thus have the potential to induce hypothyroidism in some people. This chapter provides an overview of novel small molecules that have been specifically designed or screened for their TR antagonist activity as novel treatments for hyperthyroidism. While novel compounds have been identified, to date none have been developed sufficiently to enter clinical trials. Furthermore, a discussion on other sources of TR antagonists is discussed in terms of side effects of current drugs in the clinic as well as environmental pollution. © 2018 Elsevier Inc. All rights reserved.

  16. A2A Adenosine Receptor Antagonists as Therapeutic Candidates: are they still an interesting challenge?

    Science.gov (United States)

    Cacciari, Barbara; Federico, Stephanie; Spalluto, Giampiero

    2018-04-22

    In the past decades, many efforts were done to develope ligands for the adenosine receptors, with the purpose to individuate agonists and antagonists affine and selective for each subtypes , named A1, A2A, A2B, and A3. These intense studies allowed a deeper and deeper knowledge of the nature and, moreover, of the pathophysiological roles of all the adenosine receptor subtypes. In particular, the involvment of the A2A adenosine receptor subtype in some physiological mechanisms in the brain, that could be related to important diseases such as the Parkinson's disease, encouraged the research in this field. Particular attention was given to the antagonists endowed with high affinity and selectivity since they could have a real employment in the treatment of Parkinson's disease, and some compounds, such as istradefylline, preladenant and tozadenant, are already studied in clinical trials. Actually, the role of A2A antagonists in Parkinson's disease is becoming contradictory due to contrasting results in the last studies, but, at the same time, new possible employments are emerging for this class of antagonists in cancer pathologies as much interesting to legitimate further efforts in the research of A2A ligands. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  17. Chemogenomic discovery of allosteric antagonists at the GPRC6A receptor

    DEFF Research Database (Denmark)

    Gloriam, David E.; Wellendorph, Petrine; Johansen, Lars Dan

    2011-01-01

    and pharmacological character: (1) chemogenomic lead identification through the first, to our knowledge, ligand inference between two different GPCR families, Families A and C; and (2) the discovery of the most selective GPRC6A allosteric antagonists discovered to date. The unprecedented inference of...... pharmacological activity across GPCR families provides proof-of-concept for in silico approaches against Family C targets based on Family A templates, greatly expanding the prospects of successful drug design and discovery. The antagonists were tested against a panel of seven Family A and C G protein-coupled receptors...

  18. Discovery, synthesis, selectivity modulation and DMPK characterization of 5-azaspiro[2.4]heptanes as potent orexin receptor antagonists.

    Science.gov (United States)

    Stasi, Luigi Piero; Artusi, Roberto; Bovino, Clara; Buzzi, Benedetta; Canciani, Luca; Caselli, Gianfranco; Colace, Fabrizio; Garofalo, Paolo; Giambuzzi, Silvia; Larger, Patrice; Letari, Ornella; Mandelli, Stefano; Perugini, Lorenzo; Pucci, Sabrina; Salvi, Matteo; Toro, PierLuigi

    2013-05-01

    Starting from a orexin 1 receptor selective antagonist 4,4-disubstituted piperidine series a novel potent 5-azaspiro[2.4]heptane dual orexin 1 and orexin 2 receptor antagonist class has been discovered. SAR and Pharmacokinetic optimization of this series is herein disclosed. Lead compound 15 exhibits potent activity against orexin 1 and orexin 2 receptors along with low cytochrome P450 inhibition potential, good brain penetration and oral bioavailability in rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Effects of urotensin II receptor antagonist, GSK1440115, in asthma

    Directory of Open Access Journals (Sweden)

    Alison D Portnoy

    2013-04-01

    Full Text Available Background: Urotensin II (U-II is highly expressed in the human lung and has been implicated in regulating respiratory physiology in preclinical studies. Our objective was to test antagonism of the urotensin receptor (UT by GSK1440115, a novel, competitive and selective inhibitor of the UT receptor, as a therapeutic strategy for the treatment of asthma. Methods: Safety, tolerability and pharmacokinetics (PK of single doses of GSK1440115 (1–750 mg were assessed in a Phase I, placebo-controlled study in 70 healthy subjects. In a Phase Ib study, 12 asthmatic patients were randomized into a 2-period, single-blind crossover study and treated with single doses of 750 mg GSK1440115 or placebo and given a methacholine challenge. Results: Administration of GSK1440115 was safe and well-tolerated in healthy subjects and asthmatic patients. In both studies, there was a high degree of variability in the observed PK following oral dosing with GSK1440115 at all doses. There was a marked food effect in healthy subjects at the 50 mg dose. In the presence of food at the 750 mg dose, the time to maximal concentration was between 2 and 6 hours and the terminal half-life was short at approximately 2 hours. All asthmatic patients maintained greater than the predicted concentration levels necessary to achieve predicted 96% receptor occupancy for >=3 hours (between 4-7 hours post-dose. There were no apparent trends or relationships between the systemic plasma exposure of GSK1440115 and pharmacodynamic endpoints, PC20 after methacholine challenge and FEV1, in asthmatics. Conclusion: While GSK1440115 was safe and well-tolerated, it did not induce bronchodilation in asthmatics, or protect against methacholine-induced bronchospasm, suggesting that acute UT antagonism is not likely to provide benefit as an acute bronchodilator in this patient population.

  20. Ectopic Expression of α6 and δ GABAA Receptor Subunits in Hilar Somatostatin Neurons Increases Tonic Inhibition and Alters Network Activity in the Dentate Gyrus

    Science.gov (United States)

    Tong, Xiaoping; Peng, Zechun; Zhang, Nianhui; Cetina, Yliana; Huang, Christine S.; Wallner, Martin; Otis, Thomas S.

    2015-01-01

    The role of GABAA receptor (GABAAR)-mediated tonic inhibition in interneurons remains unclear and may vary among subgroups. Somatostatin (SOM) interneurons in the hilus of the dentate gyrus show negligible expression of nonsynaptic GABAAR subunits and very low tonic inhibition. To determine the effects of ectopic expression of tonic GABAAR subtypes in these neurons, Cre-dependent viral vectors were used to express GFP-tagged GABAAR subunits (α6 and δ) selectively in hilar SOM neurons in SOM-Cre mice. In single-transfected animals, immunohistochemistry demonstrated strong expression of either the α6 or δ subunit; in cotransfected animals, both subunits were consistently expressed in the same neurons. Electrophysiology revealed a robust increase of tonic current, with progressively larger increases following transfection of δ, α6, and α6/δ subunits, respectively, indicating formation of functional receptors in all conditions and likely coassembly of the subunits in the same receptor following cotransfection. An in vitro model of repetitive bursting was used to determine the effects of increased tonic inhibition in hilar SOM interneurons on circuit activity in the dentate gyrus. Upon cotransfection, the frequency of GABAAR-mediated bursting in granule cells was reduced, consistent with a reduction in synchronous firing among hilar SOM interneurons. Moreover, in vivo studies of Fos expression demonstrated reduced activation of α6/δ-cotransfected neurons following acute seizure induction by pentylenetetrazole. The findings demonstrate that increasing tonic inhibition in hilar SOM interneurons can alter dentate gyrus circuit activity during strong stimulation and suggest that tonic inhibition of interneurons could play a role in regulating excessive synchrony within the network. SIGNIFICANCE STATEMENT In contrast to many hippocampal interneurons, somatostatin (SOM) neurons in the hilus of the dentate gyrus have very low levels of nonsynaptic GABAARs and exhibit

  1. Viability of D283 medulloblastoma cells treated with a histone deacetylase inhibitor combined with bombesin receptor antagonists.

    Science.gov (United States)

    Jaeger, Mariane; Ghisleni, Eduarda C; Fratini, Lívia; Brunetto, Algemir L; Gregianin, Lauro José; Brunetto, André T; Schwartsmann, Gilberto; de Farias, Caroline B; Roesler, Rafael

    2016-01-01

    Medulloblastoma (MB) comprises four distinct molecular subgroups, and survival remains particularly poor in patients with Group 3 tumors. Mutations and copy number variations result in altered epigenetic regulation of gene expression in Group 3 MB. Histone deacetylase inhibitors (HDACi) reduce proliferation, promote cell death and neuronal differentiation, and increase sensitivity to radiation and chemotherapy in experimental MB. Bombesin receptor antagonists potentiate the antiproliferative effects of HDACi in lung cancer cells and show promise as experimental therapies for several human cancers. Here, we examined the viability of D283 cells, which belong to Group 3 MB, treated with an HDACi alone or combined with bombesin receptor antagonists. D283 MB cells were treated with different doses of the HDACi sodium butyrate (NaB), the neuromedin B receptor (NMBR) antagonist BIM-23127, the gastrin releasing peptide receptor (GRPR) antagonist RC-3095, or combinations of NaB with each receptor antagonist. Cell viability was examined by cell counting. NaB alone or combined with receptor antagonists reduced cell viability at all doses tested. BIM-23127 alone did not affect cell viability, whereas RC-3095 at an intermediate dose significantly increased cell number. Although HDACi are promising agents to inhibit MB growth, the present results provide preliminary evidence that combining HDACi with bombesin receptor antagonists is not an effective strategy to improve the effects of HDACi against MB cells.

  2. Effects of muscarinic receptor antagonists on cocaine discrimination in wild-type mice and in muscarinic receptor M1, M2, and M4 receptor knockout mice.

    Science.gov (United States)

    Joseph, Lauren; Thomsen, Morgane

    2017-06-30

    Muscarinic M 1 /M 4 receptor stimulation can reduce abuse-related effects of cocaine and may represent avenues for treating cocaine addiction. Muscarinic antagonists can mimic and enhance effects of cocaine, including discriminative stimulus (S D ) effects, but the receptor subtypes mediating those effects are not known. A better understanding of the complex cocaine/muscarinic interactions is needed to evaluate and develop potential muscarinic-based medications. Here, knockout mice lacking M 1 , M 2 , or M 4 receptors (M 1 -/- , M 2 -/- , M 4 -/- ), as well as control wild-type mice and outbred Swiss-Webster mice, were trained to discriminate 10mg/kg cocaine from saline. Muscarinic receptor antagonists with no subtype selectivity (scopolamine), or preferential affinity at the M 1 , M 2 , or M 4 subtype (telenzepine, trihexyphenidyl; methoctramine, AQ-RA 741; tropicamide) were tested alone and in combination with cocaine. In intact animals, antagonists with high affinity at M 1 /M 4 receptors partially substituted for cocaine and increased the S D effect of cocaine, while M 2 -preferring antagonists did not substitute, and reduced the S D effect of cocaine. The cocaine-like effects of scopolamine were absent in M 1 -/- mice. The cocaine S D attenuating effects of methoctramine were absent in M 2 -/- mice and almost absent in M 1 -/- mice. The findings indicate that the cocaine-like S D effects of muscarinic antagonists are primarily mediated through M 1 receptors, with a minor contribution of M 4 receptors. The data also support our previous findings that stimulation of M 1 receptors and M 4 receptors can each attenuate the S D effect of cocaine, and show that this can also be achieved by blocking M 2 autoreceptors, likely via increased acetylcholine release. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. P2X1 Receptor Antagonists Inhibit HIV-1 Fusion by Blocking Virus-Coreceptor Interactions.

    Science.gov (United States)

    Giroud, Charline; Marin, Mariana; Hammonds, Jason; Spearman, Paul; Melikyan, Gregory B

    2015-09-01

    HIV-1 Env glycoprotein-mediated fusion is initiated upon sequential binding of Env to CD4 and the coreceptor CXCR4 or CCR5. Whereas these interactions are thought to be necessary and sufficient to promote HIV-1 fusion, other host factors can modulate this process. Previous studies reported potent inhibition of HIV-1 fusion by selective P2X1 receptor antagonists, including NF279, and suggested that these receptors play a role in HIV-1 entry. Here we investigated the mechanism of antiviral activity of NF279 and found that this compound does not inhibit HIV-1 fusion by preventing the activation of P2X1 channels but effectively blocks the binding of the virus to CXCR4 or CCR5. The notion of an off-target effect of NF279 on HIV-1 fusion is supported by the lack of detectable expression of P2X1 receptors in cells used in fusion experiments and by the fact that the addition of ATP or the enzymatic depletion of ATP in culture medium does not modulate viral fusion. Importantly, NF279 fails to inhibit HIV-1 fusion with cell lines and primary macrophages when added at an intermediate stage downstream of Env-CD4-coreceptor engagement. Conversely, in the presence of NF279, HIV-1 fusion is arrested downstream of CD4 binding but prior to coreceptor engagement. NF279 also antagonizes the signaling function of CCR5, CXCR4, and another chemokine receptor, as evidenced by the suppression of calcium responses elicited by specific ligands and by recombinant gp120. Collectively, our results demonstrate that NF279 is a dual HIV-1 coreceptor inhibitor that interferes with the functional engagement of CCR5 and CXCR4 by Env. Inhibition of P2X receptor activity suppresses HIV-1 fusion and replication, suggesting that P2X signaling is involved in HIV-1 entry. However, mechanistic experiments conducted in this study imply that P2X1 receptor is not expressed in target cells or involved in viral fusion. Instead, we found that inhibition of HIV-1 fusion by a specific P2X1 receptor antagonist, NF

  4. The 5-HT2A receptor antagonist M100907 produces antiparkinsonian effects and decreases striatal glutamate

    Directory of Open Access Journals (Sweden)

    Twum eAnsah

    2011-06-01

    Full Text Available 5-HT plays a regulatory role in voluntary movements of the basal ganglia and have a major impact on disorders of the basal ganglia such as Parkinson’s disease (PD. Clinical studies have suggested that 5-HT2 receptor antagonists may be useful in the treatment of the motor symptoms of PD. We hypothesized that 5-HT2A receptor antagonists may restore motor function by regulating glutamatergic activity in the striatum. Mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP exhibited decreased performance on the beam-walking apparatus. Peripheral administration of the 5-HT2A receptor antagonist M100907 improved performance of MPTP-treated mice on the beam-walking apparatus. In vivo microdialysis revealed an increase in striatal extracellular glutamate in MPTP-treated mice and local perfusion of M100907 into the dorsal striatum significantly decreased extracellular glutamate levels in saline and MPTP-treated mice. Our studies suggest that blockade of 5-HT2A receptors may represent a novel therapeutic target for the motor symptoms of Parkinson’s disease.

  5. AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Terry W. Moody

    2017-07-01

    Full Text Available While peptide antagonists for the gastrin-releasing peptide receptor (BB2R, neuromedin B receptor (BB1R, and bombesin (BB receptor subtype-3 (BRS-3 exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar affinity (Ki = 1.4–10.8 µM. AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca2+ in human lung cancer cells transfected with BB1R, BB2R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists.

  6. AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists

    Science.gov (United States)

    Moody, Terry W.; Tashakkori, Nicole; Mantey, Samuel A.; Moreno, Paola; Ramos-Alvarez, Irene; Leopoldo, Marcello; Jensen, Robert T.

    2017-01-01

    While peptide antagonists for the gastrin-releasing peptide receptor (BB2R), neuromedin B receptor (BB1R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB1R, BB2R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB1R, BB2R, and BRS-3 with similar affinity (Ki = 1.4–10.8 µM). AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca2+ in human lung cancer cells transfected with BB1R, BB2R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists. PMID:28785244

  7. AM-37 and ST-36 Are Small Molecule Bombesin Receptor Antagonists.

    Science.gov (United States)

    Moody, Terry W; Tashakkori, Nicole; Mantey, Samuel A; Moreno, Paola; Ramos-Alvarez, Irene; Leopoldo, Marcello; Jensen, Robert T

    2017-01-01

    While peptide antagonists for the gastrin-releasing peptide receptor (BB 2 R), neuromedin B receptor (BB 1 R), and bombesin (BB) receptor subtype-3 (BRS-3) exist, there is a need to develop non-peptide small molecule inhibitors for all three BBR. The BB agonist (BA)1 binds with high affinity to the BB 1 R, BB 2 R, and BRS-3. In this communication, small molecule BBR antagonists were evaluated using human lung cancer cells. AM-37 and ST-36 inhibited binding to human BB 1 R, BB 2 R, and BRS-3 with similar affinity ( K i = 1.4-10.8 µM). AM-13 and AM-14 were approximately an order of magnitude less potent than AM-37 and ST-36. The ability of BA1 to elevate cytosolic Ca 2+ in human lung cancer cells transfected with BB 1 R, BB 2 R, and BRS-3 was antagonized by AM-37 and ST-36. BA1 increased tyrosine phosphorylation of the EGFR and ERK in lung cancer cells, which was blocked by AM-37 and ST-36. AM-37 and ST-36 reduced the growth of lung cancer cells that have BBR. The results indicate that AM-37 and ST-36 function as small molecule BB receptor antagonists.

  8. Pharmacology of JB-9315, a new selective histamine H2-receptor antagonist.

    Science.gov (United States)

    Palacios, B; Montero, M J; Sevilla, M A; San Román, L

    1998-02-01

    1. The histamine H2-receptor antagonistic activity and antisecretory and antiulcer effects of JB-9315 were studied in comparison with the standard H2 blocker ranitidine. 2. In vitro, JB-9315 is a competitive antagonist of histamine H2 receptors in the isolated, spontaneously beating guinea-pig right atrium, with a pA2 value of 7.30 relative to a value of 7.36 for ranitidine. JB-9315 was specific for the histamine H2 receptor because, at high concentration, it did not affect histamine- or acetylcholine-induced contractions in guinea-pig isolated ileum or rat isolated duodenum, respectively. 3. JB-9315 dose dependently inhibited histamine-, pentagastrin- or carbachol-stimulated acid secretion and basal secretion in the perfused stomach preparation of the anesthetized rat. In the pylorus-ligated rat after intraperitoneal administration, total acid output over 4 h was inhibited by JB-9315 with an ID50 of 32.8 mg/kg, confirming its H2-receptor antagonist properties. 4. JB-9315 showed antiulcer activity against cold stress plus indomethacin-induced lesions with an ID50 of 6.8 mg/kg. 5. JB-9315, 50 and 100 mg/kg, inhibited macroscopic gastric hemorrhagic lesions induced by ethanol. In contrast, ranitidine (50 mg/kg) failed to reduce these lesions. 6. These results indicate that JB-9315 is a new antiulcer drug that exerts a cytoprotective effect in addition to its gastric antisecretory activity.

  9. Recent progress in the development of small-molecule glucagon receptor antagonists.

    Science.gov (United States)

    Sammons, Matthew F; Lee, Esther C Y

    2015-10-01

    The endocrine hormone glucagon stimulates hepatic glucose output via its action at the glucagon receptor (GCGr) in the liver. In the diabetic state, dysregulation of glucagon secretion contributes to abnormally elevated hepatic glucose output. The inhibition of glucagon-induced hepatic glucose output via antagonism of the GCGr using small-molecule ligands is a promising mechanism for improving glycemic control in the diabetic state. Clinical data evaluating the therapeutic potential of small-molecule GCGr antagonists is currently emerging. Recently disclosed clinical data demonstrates the potential efficacy and possible therapeutic limitations of small-molecule GCGr antagonists. Recent pre-clinical work on the development of GCGr antagonists is also summarized. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Evidence that the angiotensin at 2-receptor agonist compound 21 is also a low affinity thromboxane TXA2-receptor antagonist

    DEFF Research Database (Denmark)

    Fredgart, M.; Leurgans, T.; Stenelo, M.

    2015-01-01

    Objective: The objective of this study was to test whether Compound 21 (C21), a high-affinity, non-peptide angiotensinAT2-receptor agonist, is also an antagonist of thromboxane A2 (TXA2) receptors thus reducing both vasoconstriction and platelet aggregation. Design and method: Binding of C21...... to the TXA2 receptor was determined by TBXA2R Arrestin Biosensor Assay. Mouse mesenteric arteries were mounted in wire myographs, and responses to increasing concentrations of C21 (1nM- 10muM) were recorded during submaximal contractions with 0.1muM U46619 (TXA2 analogue) or 1muMphenylephrine. To control for......AT2-receptor specificity, arteries were pre-incubated with the AT2-receptor antagonist PD123319 (10muM), or mesenteric arteries from AT2-receptor knock-out (AT2R-/y) mice were used. An inhibitory effect of C21 (100nM - 10muM) on U46619 (0,3muM) induced platelet aggregation was examined in whole human...

  11. Discovery of a Manduca sexta Allatotropin Antagonist from a Manduca sexta Allatotropin Receptor Homology Model.

    Science.gov (United States)

    Kai, Zhen-Peng; Zhu, Jing-Jing; Deng, Xi-Le; Yang, Xin-Ling; Chen, Shan-Shan

    2018-04-03

    Insect G protein coupled receptors (GPCRs) have important roles in modulating biology, physiology and behavior. They have been identified as candidate targets for next-generation insecticides, yet these targets have been relatively poorly exploited for insect control. In this study, we present a pipeline of novel Manduca sexta allatotropin (Manse-AT) antagonist discovery with homology modeling, docking, molecular dynamics simulation and structure-activity relationship. A series of truncated and alanine-replacement analogs of Manse-AT were assayed for the stimulation of juvenile hormone biosynthesis. The minimum sequence required to retain potent biological activity is the C -terminal amidated octapeptide Manse-AT (6-13). We identified three residues essential for bioactivity (Thr⁴, Arg6 and Phe⁸) by assaying alanine-replacement analogs of Manse-AT (6-13). Alanine replacement of other residues resulted in reduced potency but bioactivity was retained. The 3D structure of the receptor (Manse-ATR) was built and the binding pocket was identified. The binding affinities of all the analogs were estimated by calculating the free energy of binding. The calculated binding affinities corresponded to the biological activities of the analogs, which supporting our localization of the binding pocket. Then, based on the docking and molecular dynamics studies of Manse-AT (10-13), we described it can act as a potent Manse-AT antagonist. The antagonistic effect on JH biosynthesis of Manse-AT (10-13) validated our hypothesis. The IC 50 value of antagonist Manse-AT (10-13) is 0.9 nM. The structure-activity relationship of antagonist Manse-AT (10-13) was also studied for the further purpose of investigating theoretically the structure factors influencing activity. These data will be useful for the design of new Manse-AT agonist and antagonist as potential pest control agents.

  12. Discovery of a Manduca sexta Allatotropin Antagonist from a Manduca sexta Allatotropin Receptor Homology Model

    Directory of Open Access Journals (Sweden)

    Zhen-Peng Kai

    2018-04-01

    Full Text Available Insect G protein coupled receptors (GPCRs have important roles in modulating biology, physiology and behavior. They have been identified as candidate targets for next-generation insecticides, yet these targets have been relatively poorly exploited for insect control. In this study, we present a pipeline of novel Manduca sexta allatotropin (Manse-AT antagonist discovery with homology modeling, docking, molecular dynamics simulation and structure-activity relationship. A series of truncated and alanine-replacement analogs of Manse-AT were assayed for the stimulation of juvenile hormone biosynthesis. The minimum sequence required to retain potent biological activity is the C-terminal amidated octapeptide Manse-AT (6–13. We identified three residues essential for bioactivity (Thr4, Arg6 and Phe8 by assaying alanine-replacement analogs of Manse-AT (6–13. Alanine replacement of other residues resulted in reduced potency but bioactivity was retained. The 3D structure of the receptor (Manse-ATR was built and the binding pocket was identified. The binding affinities of all the analogs were estimated by calculating the free energy of binding. The calculated binding affinities corresponded to the biological activities of the analogs, which supporting our localization of the binding pocket. Then, based on the docking and molecular dynamics studies of Manse-AT (10–13, we described it can act as a potent Manse-AT antagonist. The antagonistic effect on JH biosynthesis of Manse-AT (10–13 validated our hypothesis. The IC50 value of antagonist Manse-AT (10–13 is 0.9 nM. The structure-activity relationship of antagonist Manse-AT (10–13 was also studied for the further purpose of investigating theoretically the structure factors influencing activity. These data will be useful for the design of new Manse-AT agonist and antagonist as potential pest control agents.

  13. Allosteric interactions between agonists and antagonists within the adenosine A2A receptor-dopamine D2 receptor heterotetramer.

    Science.gov (United States)

    Bonaventura, Jordi; Navarro, Gemma; Casadó-Anguera, Verònica; Azdad, Karima; Rea, William; Moreno, Estefanía; Brugarolas, Marc; Mallol, Josefa; Canela, Enric I; Lluís, Carme; Cortés, Antoni; Volkow, Nora D; Schiffmann, Serge N; Ferré, Sergi; Casadó, Vicent

    2015-07-07

    Adenosine A2A receptor (A2AR)-dopamine D2 receptor (D2R) heteromers are key modulators of striatal neuronal function. It has been suggested that the psychostimulant effects of caffeine depend on its ability to block an allosteric modulation within the A2AR-D2R heteromer, by which adenosine decreases the affinity and intrinsic efficacy of dopamine at the D2R. We describe novel unsuspected allosteric mechanisms within the heteromer by which not only A2AR agonists, but also A2AR antagonists, decrease the affinity and intrinsic efficacy of D2R agonists and the affinity of D2R antagonists. Strikingly, these allosteric modulations disappear on agonist and antagonist coadministration. This can be explained by a model that considers A2AR-D2R heteromers as heterotetramers, constituted by A2AR and D2R homodimers, as demonstrated by experiments with bioluminescence resonance energy transfer and bimolecular fluorescence and bioluminescence complementation. As predicted by the model, high concentrations of A2AR antagonists behaved as A2AR agonists and decreased D2R function in the brain.

  14. 5-HT2A receptor antagonists improve motor impairments in the MPTP mouse model of Parkinson's disease

    OpenAIRE

    Ferguson, Marcus C.; Nayyar, Tultul; Deutch, Ariel Y.; Ansah, Twum A.

    2010-01-01

    Clinical observations have suggested that ritanserin, a 5-HT2A/C receptor antagonist may reduce motor deficits in persons with Parkinson's Disease (PD). To better understand the potential antiparkinsonian actions of ritanserin, we compared the effects of ritanserin with the selective 5-HT2A receptor antagonist M100907 and the selective 5-HT2C receptor antagonist SB 206553 on motor impairments in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP-treated mice exhibited...

  15. Design, synthesis and biological activity of 6-substituted carbamoyl benzimidazoles as new nonpeptidic angiotensin II AT₁ receptor antagonists.

    Science.gov (United States)

    Zhang, Jun; Wang, Jin-Liang; Zhou, Zhi-Ming; Li, Zhi-Huai; Xue, Wei-Zhe; Xu, Di; Hao, Li-Ping; Han, Xiao-Feng; Fei, Fan; Liu, Ting; Liang, Ai-Hua

    2012-07-15

    A series of 6-substituted carbamoyl benzimidazoles were designed and synthesised as new nonpeptidic angiotensin II AT(1) receptor antagonists. The preliminary pharmacological evaluation revealed a nanomolar AT(1) receptor binding affinity for all compounds in the series, and a potent antagonistic activity in an isolated rabbit aortic strip functional assay for compounds 6f, 6g, 6h and 6k was also demonstrated. Furthermore, evaluation in spontaneous hypertensive rats and a preliminary toxicity evaluation showed that compound 6g is an orally active AT(1) receptor antagonist with low toxicity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Serotonergic 5-HT6 Receptor Antagonists: Heterocyclic Chemistry and Potential Therapeutic Significance.

    Science.gov (United States)

    Bali, Alka; Singh, Shalu

    2015-01-01

    The serotonin 5-HT(6) receptor (5- HT(6)R) is amongst the recently discovered serotonergic receptors with almost exclusive localization in the brain. Hence, this receptor is fast emerging as a promising target for cognition enhancement in central nervous system (CNS) diseases such as Alzheimer's disease (cognitive function), obesity, schizophrenia and anxiety. The last decade has seen a surge of literature reports on the functional role of this receptor in learning and memory processes and investigations related to the chemistry and pharmacology of 5-HT(6) receptor ligands, especially 5- HT(6) receptor antagonists. Studies show the involvement of multiple neurotransmitter systems in cognitive enhancement by 5-HT(6)R antagonists including cholinergic, glutamatergic, and GABAergic systems. Several of the 5-HT(6)R ligands are indole based agents bearing structural similarity to the endogenous neurotransmitter serotonin. Based on the pharmacophoric models proposed for these agents, drug designing has been carried out incorporating various heterocyclic replacements for the indole nucleus. In this review, we have broadly summarized the medicinal chemistry and current status of this fairly recent class of drugs along with their potential therapeutic applications.

  17. Progesterone receptor antagonist CDB-4124 increases depression-like behavior in mice without affecting locomotor ability.

    Science.gov (United States)

    Beckley, Ethan H; Scibelli, Angela C; Finn, Deborah A

    2011-07-01

    Progesterone withdrawal has been proposed as an underlying factor in premenstrual syndrome and postpartum depression. Progesterone withdrawal induces forced swim test (FST) immobility in mice, a depression-like behavior, but the contribution of specific receptors to this effect is unclear. The role of progesterone's GABA(A) receptor-modulating metabolite allopregnanolone in depression- and anxiety-related behaviors has been extensively documented, but little attention has been paid to the role of progesterone receptors. We administered the classic progesterone receptor antagonist mifepristone (RU-38486) and the specific progesterone receptor antagonist CDB-4124 to mice that had been primed with progesterone for five days, and found that both compounds induced FST immobility reliably, robustly, and in a dose-dependent fashion. Although CDB-4124 increased FST immobility, it did not suppress initial activity in a locomotor test. These findings suggest that decreased progesterone receptor activity contributes to depression-like behavior in mice, consistent with the hypothesis that progesterone withdrawal may contribute to the symptoms of premenstrual syndrome or postpartum depression. Copyright © 2010 Elsevier Ltd. All rights reserved.

  18. Progesterone receptor antagonist CDB-4124 increases depression-like behavior in mice without affecting locomotor ability

    Science.gov (United States)

    Beckley, Ethan H.; Scibelli, Angela C.; Finn, Deborah A.

    2010-01-01

    Progesterone withdrawal has been proposed as an underlying factor in premenstrual syndrome and postpartum depression. Progesterone withdrawal induces forced swim test (FST) immobility in mice, a depression-like behavior, but the contribution of specific receptors to this effect is unclear. The role of progesterone’s GABAA receptor-modulating metabolite allopregnanolone in depression- and anxiety-related behaviors has been extensively documented, but little attention has been paid to the role of progesterone receptors. We administered the classic progesterone receptor antagonist mifepristone (RU-38486) and the specific progesterone receptor antagonist CDB-4124 to mice that had been primed with progesterone for five days, and found that both compounds induced FST immobility reliably, robustly, and in a dose-dependent fashion. Although CDB-4124 increased FST immobility, it did not suppress initial activity in a locomotor test. These findings suggest that decreased progesterone receptor activity contributes to depression-like behavior in mice, consistent with the hypothesis that progesterone withdrawal may contribute to the symptoms of premenstrual syndrome or postpartum depression. PMID:21163582

  19. Pharmacological significance of the interplay between angiotensin receptors: MAS receptors as putative final mediators of the effects elicited by angiotensin AT1 receptors antagonists.

    Science.gov (United States)

    Pernomian, Larissa; Pernomian, Laena; Gomes, Mayara S; da Silva, Carlos H T P

    2015-12-15

    The interplay between angiotensin AT1 receptors and MAS receptors relies on several inward regulatory mechanisms from renin-angiotensin system (RAS) including the functional crosstalk between angiotensin II and angiotensin-(1-7), the competitive AT1 antagonism exhibited by angiotensin-(1-7), the antagonist feature assigned to AT1/MAS heterodimerization on AT1 signaling and the AT1-mediated downregulation of angiotensin-converting enzyme 2 (ACE2). Recently, such interplay has acquired an important significance to RAS Pharmacology since a few studies have supporting strong evidences that MAS receptors mediate the effects elicited by AT1 antagonists. The present Perspective provides an overview of the regulatory mechanisms involving AT1 and MAS receptors, their significance to RAS Pharmacology and the future directions on the interplay between angiotensin receptors. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. MIBE acts as antagonist ligand of both estrogen receptor α and GPER in breast cancer cells.

    Science.gov (United States)

    Lappano, Rosamaria; Santolla, Maria Francesca; Pupo, Marco; Sinicropi, Maria Stefania; Caruso, Anna; Rosano, Camillo; Maggiolini, Marcello

    2012-01-17

    The multiple biological responses to estrogens are mainly mediated by the classical estrogen receptors ERα and ERβ, which act as ligand-activated transcription factors. ERα exerts a main role in the development of breast cancer; therefore, the ER antagonist tamoxifen has been widely used although its effectiveness is limited by de novo and acquired resistance. Recently, GPR30/GPER, a member of the seven-transmembrane G protein-coupled receptor family, has been implicated in mediating the effects of estrogens in various normal and cancer cells. In particular, GPER triggered gene expression and proliferative responses induced by estrogens and even ER antagonists in hormone-sensitive tumor cells. Likewise, additional ER ligands showed the ability to bind to GPER eliciting promiscuous and, in some cases, opposite actions through the two receptors. We synthesized a novel compound (ethyl 3-[5-(2-ethoxycarbonyl-1-methylvinyloxy)-1-methyl-1H-indol-3-yl]but-2-enoate), referred to as MIBE, and investigated its properties elicited through ERα and GPER in breast cancer cells. Molecular modeling, binding experiments and functional assays were performed in order to evaluate the biological action exerted by MIBE through ERα and GPER in MCF7 and SkBr3 breast cancer cells. MIBE displayed the ability to act as an antagonist ligand for ERα and GPER as it elicited inhibitory effects on gene transcription and growth effects by binding to both receptors in breast cancer cells. Moreover, GPER was required for epidermal growth factor receptor (EGFR) and ERK activation by EGF as ascertained by using MIBE and performing gene silencing experiments. Our findings provide novel insights on the functional cross-talk between GPER and EGFR signaling. Furthermore, the exclusive antagonistic activity exerted by MIBE on ERα and GPER could represent an innovative pharmacological approach targeting breast carcinomas which express one or both receptors at the beginning and/or during tumor

  1. Preparation and Characterization of an Antibody Antagonist That Targets the Porcine Growth Hormone Receptor

    Directory of Open Access Journals (Sweden)

    Huanzhong Cui

    2016-10-01

    Full Text Available A series of antagonists specifically targeting growth hormone receptors (GHR in different species, such as humans, rats, bovines, and mice, have been designed; however, there are currently no antagonists that target the porcine growth hormone (GH. Therefore, in this study, we developed and characterized a porcine GHR (pGHR antibody antagonist (denoted by AN98 via the hybridoma technique. The results from enzyme-linked immunosorbent assay, fluorescence activated cell sorter, indirect immunoinfluscent assay, and competitive receptor binding analysis showed that AN98 could specifically recognize pGHR, and further experiments indicated that AN98 could effectively inhibit pGH-induced signalling in CHO-pGHR cells and porcine hepatocytes. In addition, AN98 also inhibited GH-induced insulin-like growth factor-1 (IGF-1 secretion in porcine hepatocytes. In summary, these findings indicated that AN98, as a pGHR-specific antagonist, has potential applications in pGH-pGHR-related research on domestic pigs.

  2. Design and synthesis of aryloxypropanolamine as β3-adrenergic receptor antagonist in cancer and lipolysis.

    Science.gov (United States)

    Jin, Jiyu; Miao, Chunxiao; Wang, Zhilong; Zhang, Wanli; Zhang, Xiongwen; Xie, Xin; Lu, Wei

    2018-04-25

    β-adrenergic receptors (β-ARs) are broadly distributed in various tissues and regulate a panel of important physiological functions and disease states including cancer. Above all, β 3 -adrenergic receptor (β 3 -AR) plays a significant role in regulating lipolysis and thermogenesis in adipose tissue. In this study, we designed and synthesized a series of novel L-748,337 derivatives as selective human β 3 -AR antagonists. Among all the tested L-748,337 analogs, compound 23d was found to display 23-fold more potent β 3 -AR antagonist activity (EC 50  = 0.5117 nM) than L-748,337 (EC 50  = 11.91 nM). In vivo, compound 23d could alleviate weight loss and inhibit tumor growth in C26 tumor cachexia animal model. Copyright © 2018 Elsevier Masson SAS. All rights reserved.

  3. The safety of interleukin-1 receptor antagonist (anakinra in the treatment of rheumatoid arthritis

    Directory of Open Access Journals (Sweden)

    L. Riente

    2011-09-01

    Full Text Available The safety profile of interleukin-1 receptor antagonist (anakinra has been studied with randomised, placebo-controlled trials involving 2932 patients affected by rheumatoid arthritis. The most frequently reported adverse events were represented by injection site reactions (71% and headache (13.6%. No statistically significant difference in the incidence of infections was observed among the patients treated with the interleukin-1 receptor antagonist and the patients receiving placebo. In particular, the incidence of serious infections was 1,8% in rheumatoid arthritis patients on anakinra therapy and 0,7% in patients on placebo. The reported serious infections consisted of pneumonia, cellulitis, bone and joint infections, bursitis. No case of opportunistic infections or tubercolosis was observed. The results of clinical studies suggest that anakinra is a new well-tolerated drug for the treatment of patients affected by rheumatoid arthritis.

  4. Potentiation of the gastric antisecretory activity of histamine H2-receptor antagonists by clebopride.

    Science.gov (United States)

    Fernández, A G; Massingham, R; Roberts, D J

    1988-05-01

    The substituted benzamide, clebopride, at doses (0.03-3 mg kg-1 i.p.) that were without effect per se on the secretion of gastric acid in pylorus ligated (Shay) rats, potentiated the antisecretory effects of the histamine H2 receptor antagonists cimetidine and ranitidine in this model but not those of the muscarine receptor antagonist pirenzepine nor those of the proton pump inhibitor omeprazole. By contrast, clebopride was without influence on the inhibitory effects of cimetidine on pentagastrin-induced secretion in perfused stomach (Ghosh and Schild) preparations in anaesthetized rats. The significance of these findings is discussed in relation to the previously described potentiating effects of clebopride on the anti-ulcer activity of cimetidine in various experimental models, and the potential beneficial effects of such combined therapy in the clinic.

  5. Biaryls as potent, tunable dual neurokinin 1 receptor antagonists and serotonin transporter inhibitors.

    Science.gov (United States)

    Degnan, Andrew P; Tora, George O; Han, Ying; Rajamani, Ramkumar; Bertekap, Robert; Krause, Rudolph; Davis, Carl D; Hu, Joanna; Morgan, Daniel; Taylor, Sarah J; Krause, Kelly; Li, Yu-Wen; Mattson, Gail; Cunningham, Melissa A; Taber, Matthew T; Lodge, Nicholas J; Bronson, Joanne J; Gillman, Kevin W; Macor, John E

    2015-08-01

    Depression is a serious illness that affects millions of patients. Current treatments are associated with a number of undesirable side effects. Neurokinin 1 receptor (NK1R) antagonists have recently been shown to potentiate the antidepressant effects of serotonin-selective reuptake inhibitors (SSRIs) in a number of animal models. Herein we describe the optimization of a biaryl chemotype to provide a series of potent dual NK1R antagonists/serotonin transporter (SERT) inhibitors. Through the choice of appropriate substituents, the SERT/NK1R ratio could be tuned to afford a range of target selectivity profiles. This effort culminated in the identification of an analog that demonstrated oral bioavailability, favorable brain uptake, and efficacy in the gerbil foot tap model. Ex vivo occupancy studies with compound 58 demonstrated the ability to maintain NK1 receptor saturation (>88% occupancy) while titrating the desired level of SERT occupancy (11-84%) via dose selection. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Additional lesions detected in therapeutic scans with 177Lu-DOTATATE reflect higher affinity of 177Lu-DOTATATE for somatostatin receptors.

    Science.gov (United States)

    Mirzaei, Siroos; Bastati, Brigitte; Lipp, Rainer W; Knoll, Peter; Zojer, Niklas; Ludwig, Heinz

    2011-01-01

    Peptide receptor-targeted radionuclide therapy (PRRT) of somatostatin receptor (SR)-expressing neuroendocrine tumors (NETs) has become an established therapeutic option in patients with advanced NETs. The aim of this study was to compare the lesion detection rate of (99m)Tc-EDDA/HYNIC-TOC, a newly developed tracer for NET imaging, with (177)Lu-DOTATATE used for PRRT. 8 patients (4 women, 4 men, age range 46-76 years) with histologically proven NETs, who showed high SR loads by (99m)Tc-EDDA/HYNIC-TOC scintigraphy, were treated with (177)Lu-DOTATATE. After treatment, all patients were subjected to whole-body scintigraphy with additional low-dose single-photon emission computed tomography (SPECT-CT) of the chest and abdomen. All patients demonstrated (177)Lu-DOTATATE accumulation in all lesions previously detected by (99m)Tc- EDDA/HYNIC-TOC scintigraphy. Three patients showed additional lesions in the liver and lungs. SPECT-CT after (177)Lu-DOTATATE therapy may be helpful in detecting additional lesions not seen using (99m)Tc-EDDA/HYNIC-TOC. This could reflect the broader affinity of (177)Lu-DOTATATE for SRs compared with (99m)Tc-EDDA/HYNIC-TOC. Copyright © 2011 S. Karger AG, Basel.

  7. How microelectrode array-based chick forebrain neuron biosensors respond to glutamate NMDA receptor antagonist AP5 and GABAA receptor antagonist musimol

    Directory of Open Access Journals (Sweden)

    Serena Y. Kuang

    2016-09-01

    Full Text Available We have established a long-term, stable primary chick forebrain neuron (FBN culture on a microelectrode array platform as a biosensor system for neurotoxicant screening and for neuroelectrophysiological studies for multiple purposes. This paper reports some of our results, which characterize the biosensor pharmacologically. Dose-response experiments were conducted using NMDA receptor antagonist AP5 and GABAA receptor agonist musimol (MUS. The chick FBN biosensor (C-FBN-biosensor responds to the two agents in a pattern similar to that of rodent counterparts; the estimated EC50s (the effective concentration that causes 50% inhibition of the maximal effect are 2.3 μM and 0.25 μM, respectively. Intercultural and intracultural reproducibility and long-term reusability of the C-FBN-biosensor are addressed and discussed. A phenomenon of sensitization of the biosensor that accompanies intracultural reproducibility in paired dose-response experiments for the same agent (AP5 or MUS is reported. The potential application of the C-FBN-biosensor as an alternative to rodent biosensors in shared sensing domains (NMDA receptor and GABAA receptor is suggested. Keywords: Biosensor, Microelectrode array, Neurotoxicity, Chick forebrain neuron, AP5, Musimol

  8. Radioautographic localization of somatostatin-14 and somatostatin-28 binding sites in the rat brain

    International Nuclear Information System (INIS)

    Leroux, P.; Pelletier, G.

    1984-01-01

    Somatostatin-14 (S14) and its precursor, somatostatin-28 (S28), are widely distributed throughout the rat brain, suggesting that they could act as neurotransmitter or neuromodulator in the central nervous system. The present study was undertaken to study the localization of S14 and S28 receptors in the rat brain determined by ''in vitro'' radioautography. The study performed on slide mounted frozen brain section with iodinated S14 and S28 analogs revealed an identical distribution of binding sites for the two forms of somatostatin. A good correlation could be observed between receptor distribution and immunohistologically localized neuropeptides except for striatum and hypothalamus. However, receptors were not detectable in the hypothalamus and were found in low concentration in the caudate-putamen nucleus, two regions containing high amounts of S28 and S14, suggesting a high occupancy of receptors in these areas by endogenous peptides or an inverse correlation between receptor and peptide concentrations

  9. A review of granisetron, 5-hydroxytryptamine3 receptor antagonists, and other antiemetics.

    Science.gov (United States)

    Hsu, Eric S

    2010-01-01

    Nausea and vomiting are 2 of the most upsetting adverse reactions of chemotherapy. Current guidelines propose 5-hydroxytryptamine3 (5-HT3) receptor antagonists as a pharmacologic intervention for acute and delayed nausea and vomiting [chemotherapy-induced nausea and vomiting (CINV)] associated with moderately and highly emetogenic chemotherapy. Meanwhile, both postoperative nausea and vomiting (PONV) and postdischarge nausea and vomiting are challenging situations after surgeries and procedures. Prophylactic and therapeutic combinations of antiemetics are recommended in patients at high risk of suffering from PONV and postdischarge nausea and vomiting. Granisetron (Kytril) is a selective 5-HT3 receptor antagonist that does not induce or inhibit the hepatic cytochrome P-450 system in vitro. There are also 4 other antagonists of 5-HT3 receptor (dolasetron, ondansetron, palonosetron, and tropisetron) being metabolized via the CYP2D6 and are subject to potential genetic polymorphism. The launch of a new class of antiemetics, the substance P/neurokinin1 receptor antagonists, was attributed to the scientific update on the central generator responsible for emesis and role of substance P. There has been mounting interest in exploring integrative medicine, either acupuncture or acustimulation of P6 (Nei-Kuwan), to complement the western medicine for prevention and management of nausea and vomiting. The potential application of cannabinoids, either alone or in combination with other agents of different mechanism, could contribute further to improve outcome in CINV. Implementation of future treatment guidelines for more effective management of CINV and PONV could certainly improve the efficacy and outcome of cancer and postoperative care.

  10. NMDA or 5-HT receptor antagonists impair memory reconsolidation and induce various types of amnesia.

    Science.gov (United States)

    Nikitin, V P; Solntseva, S V; Kozyrev, S A; Nikitin, P V; Shevelkin, A V

    2018-06-01

    Elucidation of amnesia mechanisms is one of the central problems in neuroscience with immense practical application. Previously, we found that conditioned food presentation combined with injection of a neurotransmitter receptor antagonist or protein synthesis inhibitor led to amnesia induction. In the present study, we investigated the time course and features of two amnesias: induced by impairment of memory reconsolidation using an NMDA glutamate receptor antagonist (MK-801) and a serotonin receptor antagonist (methiothepin, MET) on snails trained with food aversion conditioning. During the early period of amnesia (types of amnesia. Retraining an on 1st or 3rd day of amnesia induction facilitated memory formation, i.e. the number of CS + US pairings was lower than at initial training. On the 10th or 30th day after the MET/reminder, the number of CS + US pairings did not change between initial training and retraining. Retraining on the 10th or 30th day following the MK-801/reminder in the same or a new context of learning resulted in short, but not long-term, memory, and the number of CS + US pairings was higher than at the initial training. This type of amnesia was specific to the CS we used at initial training, since long-term memory for another kind of CS could be formed in the same snails. The attained results suggest that disruption of memory reconsolidation using antagonists of serotonin or NMDA glutamate receptors induced amnesias with different abilities to form long-term memory during the late period of development. Copyright © 2018 Elsevier B.V. All rights reserved.

  11. In vitro H1-receptor antagonist activity of methanolic extract of tuber of Stephania glabra

    Directory of Open Access Journals (Sweden)

    Nisar Ahmad Khan

    2010-06-01

    Full Text Available In the present study, methanolic extract of tuber of Stephania glabra was evaluated for H1-bloker activity by employing in vitro screening models of guinea pig ileum and goat tracheal chain preparation. Goat isolated trachea and guinea pig ileum contracted to histamine in a dose-dependent manner while chlorpheniramine blocked this effect. The methanolic extract produced significant dose-dependent H1-receptor antagonist activity by blocking histamine-induced contraction.

  12. Extended N-Arylsulfonylindoles as 5-HT6 Receptor Antagonists: Design, Synthesis & Biological Evaluation

    Directory of Open Access Journals (Sweden)

    Gonzalo Vera

    2016-08-01

    Full Text Available Based on a known pharmacophore model for 5-HT6 receptor antagonists, a series of novel extended derivatives of the N-arylsulfonyindole scaffold were designed and identified as a new class of 5-HT6 receptor modulators. Eight of the compounds exhibited moderate to high binding affinities and displayed antagonist profile in 5-HT6 receptor functional assays. Compounds 2-(4-(2-methoxyphenylpiperazin-1-yl-1-(1-tosyl-1H-indol-3-ylethanol (4b, 1-(1-(4-iodophenylsulfonyl-1H-indol-3-yl-2-(4-(2-methoxyphenylpiperazin-1-ylethanol (4g and 2-(4-(2-methoxyphenylpiperazin-1-yl-1-(1-(naphthalen-1-ylsulfonyl-1H-indol-3-ylethanol (4j showed the best binding affinity (4b pKi = 7.87; 4g pKi = 7.73; 4j pKi = 7.83. Additionally, compound 4j was identified as a highly potent antagonist (IC50 = 32 nM in calcium mobilisation functional assay.

  13. Emerging growth factor receptor antagonists for the treatment of renal cell carcinoma.

    Science.gov (United States)

    Zahoor, Haris; Rini, Brian I

    2016-12-01

    The landscape of systemic treatment for metastatic renal cell carcinoma (RCC) has dramatically changed with the introduction of targeted agents including vascular endothelial growth factor (VEGF) inhibitors. Recently, multiple new agents including growth factor receptor antagonists and a checkpoint inhibitor were approved for the treatment of refractory metastatic RCC based on encouraging benefit shown in clinical trials. Areas covered: The background and biological rationale of existing treatment options including a brief discussion of clinical trials which led to their approval, is presented. This is followed by reviewing the limitations of these therapeutic options, medical need to develop new treatments and major goals of ongoing research. We then discuss two recently approved growth factor receptor antagonists i.e. cabozantinib and lenvatinib, and a recently approved checkpoint inhibitor, nivolumab, and issues pertaining to drug development, and future directions in treatment of metastatic RCC. Expert opinion: Recently approved growth factor receptor antagonists have shown encouraging survival benefit but associated drug toxicity is a major issue. Nivolumab, a programmed death 1 (PD-1) checkpoint inhibitor, has similarly shown survival benefit and is well tolerated. With multiple options now available in this patient population, the right sequence of these agents remains to be determined.

  14. New insights into the stereochemical requirements of the bradykinin B2 receptor antagonists binding

    Science.gov (United States)

    Lupala, Cecylia S.; Gomez-Gutierrez, Patricia; Perez, Juan J.

    2016-01-01

    Bradykinin (BK) is a member of the kinin family, released in response to inflammation, trauma, burns, shock, allergy and some cardiovascular diseases, provoking vasodilatation and increased vascular permeability among other effects. Their actions are mediated through at least two G-protein coupled receptors, B1 a receptor up-regulated during inflammation episodes or tissue trauma and B2 that is constitutively expressed in a variety of cell types. The goal of the present work is to carry out a structure-activity study of BK B2 antagonism, taking into account the stereochemical features of diverse non-peptide antagonists and the way these features translate into ligand anchoring points to complementary regions of the receptor, through the analysis of the respective ligand-receptor complex. For this purpose an atomistic model of the BK B2 receptor was built by homology modeling and subsequently refined embedded in a lipid bilayer by means of a 600 ns molecular dynamics trajectory. The average structure from the last hundred nanoseconds of the molecular dynamics trajectory was energy minimized and used as model of the receptor for docking studies. For this purpose, a set of compounds with antagonistic profile, covering maximal diversity were selected from the literature. Specifically, the set of compounds include Fasitibant, FR173657, Anatibant, WIN64338, Bradyzide, CHEMBL442294, and JSM10292. Molecules were docked into the BK B2 receptor model and the corresponding complexes analyzed to understand ligand-receptor interactions. The outcome of this study is summarized in a 3D pharmacophore that explains the observed structure-activity results and provides insight into the design of novel molecules with antagonistic profile. To prove the validity of the pharmacophore hypothesized a virtual screening process was also carried out. The pharmacophore was used as query to identify new hits using diverse databases of molecules. The results of this study revealed a set of new

  15. Differential binding of urokinase and peptide antagonists to the urokinase receptor

    DEFF Research Database (Denmark)

    Engelholm, L H; Behrendt, N

    2001-01-01

    though these sequences contain very few substitutions relative to the human uPAR, the receptor protein products differ markedly in terms of ligand selectivity. Thus, a well described competitive peptide antagonist directed against the human uPAR reacts with only one of the monkey receptors (chimpanzee u......PAR), in spite of the fact that uPAR from all of the four species cross-reacts with human uPA. Notably, uPAR from African green monkey, which is completely devoid of reactivity with the peptide, contains only three substitutions relative to chimpanzee uPAR in the molecular regions critical for binding...

  16. No effect of angiotensin II AT(2)-receptor antagonist PD 123319 on cerebral blood flow autoregulation

    DEFF Research Database (Denmark)

    Estrup, T M; Paulson, O B; Strandgaard, S

    2001-01-01

    Blockade of the renin-angiotensin system with angiotensin-converting enzyme inhibitors (ACE-I) or angiotensin AT1-receptor antagonists shift the limits of autoregulation of cerebral blood flow (CBF) towards lower blood pressure (BP). The role of AT2-receptors in the regulation of the cerebral...... group. CBF was measured by the intracarotid 133xenon injection method and BP was raised by noradrenaline infusion and lowered by controlled haemorrhage in separate groups of rats. The limits of autoregulation were determined by computed least-sum-of-squares analysis. PD 123319 did not influence baseline...

  17. Examining SLV-323, a novel NK1 receptor antagonist, in a chronic psychosocial stress model for depression

    NARCIS (Netherlands)

    Czeh, B; Pudovkina, O; van der Hart, MGC; Simon, M; Heilbronner, U; Michaelis, T; Watanabe, T; Frahm, J; Fuchs, E

    Rationale: Substance P antagonists have been proposed as candidates for a new class of antidepressant compounds. Objectives: We examined the effects of SLV-323, a novel neurokinin 1 receptor (NK1R) antagonist, in the chronic psychosocial stress paradigm of adult male tree shrews. Methods: Animals

  18. 99mTc-N4-[Tyr3]Octreotate Versus 99mTc-EDDA/HYNIC-[Tyr3]Octreotide: an intrapatient comparison of two novel Technetium-99m labeled tracers for somatostatin receptor scintigraphy.

    Science.gov (United States)

    Gabriel, Michael; Decristoforo, Clemens; Maina, Theodosia; Nock, Berthold; vonGuggenberg, Elisabeth; Cordopatis, Paul; Moncayo, Roy

    2004-02-01

    Tetraamine-[Tyr3]octreotate (Demotate) is a somatostatin (SST) analogue that can be easily labeled with 99mTc at high specific activities and showed promising preclinical properties for SST receptor scintigraphy. This study reports on the first intra-patient comparison of 99mTc-Demotate and another 99mTc-labeled SST analogue, 99mTc-EDDA/HYNIC-TOC (HYNIC-TOC). Five patients with carcinoid tumors (n = 2) and endocrine pancreatic tumors (n = 3) were investigated with both radiopharmaceuticals. 99mTc-Demotate rapidly visualized somatostatin receptor positive tumors as early as 15 minutes post-injection (p.i.) with maximum tumor uptake and tumor/organ ratios already 1 hour p.i. Organs of predominant physiological uptake were the spleen and the kidneys with no intestinal excretion detectable up to 24 hours. 99mTc-Demotate exhibited faster pharmacokinetic properties compared to HYNIC-TOC. Tumor/organ ratios at equivalent time points were higher or comparable for 99mTc-Demotate in three patients with a matching scan result. Equivocal findings were observed in two patients, i.e. comparable uptake behavior in larger lesions with differences in smaller ones. 99mTc-Demotate is a promising agent for somatostatin receptor scintigraphy providing images of excellent quality as early as 1 hour after injection.

  19. Early Use of the NMDA Receptor Antagonist Ketamine in Refractory and Superrefractory Status Epilepticus

    Directory of Open Access Journals (Sweden)

    F. A. Zeiler

    2015-01-01

    Full Text Available Refractory status epilepticus (RSE and superrefractory status epilepticus (SRSE pose a difficult clinical challenge. Multiple cerebral receptor and transporter changes occur with prolonged status epilepticus leading to pharmacoresistance patterns unfavorable for conventional antiepileptics. In particular, n-methyl-d-aspartate (NMDA receptor upregulation leads to glutamate mediated excitotoxicity. Targeting these NMDA receptors may provide a novel approach to otherwise refractory seizures. Ketamine has been utilized in RSE. Recent systematic review indicates 56.5% and 63.5% cessation in seizures in adults and pediatrics, respectively. No complications were described. We should consider earlier implementation of ketamine or other NMDA receptor antagonists, for RSE. Prospective study of early implementation of ketamine should shed light on the role of such medications in RSE.

  20. 5α-Bile alcohols function as farnesoid X receptor antagonists

    International Nuclear Information System (INIS)

    Nishimaki-Mogami, Tomoko; Kawahara, Yosuke; Tamehiro, Norimasa; Yoshida, Takemi; Inoue, Kazuhide; Ohno, Yasuo; Nagao, Taku; Une, Mizuho

    2006-01-01

    The farnesoid X receptor (FXR) is a bile acid/alcohol-activated nuclear receptor that regulates lipid homeostasis. Unlike other steroid receptors, FXR binds bile acids in an orientation that allows the steroid nucleus A to face helix 12 in the receptor, a crucial domain for coactivator-recruitment. Because most naturally occurring bile acids and alcohols contain a cis-oriented A, which is distinct from that of other steroids and cholesterol metabolites, we investigated the role of this 5β-configuration in FXR activation. The results showed that the 5β-(A/B cis) bile alcohols 5β-cyprinol and bufol are potent FXR agonists, whereas their 5α-(A/B trans) counterparts antagonize FXR transactivation and target gene expression. Both isomers bound to FXR, but their ability to induce coactivator-recruitment and thereby induce transactivation differed. These findings suggest a critical role for the A orientation of bile salts in agonist/antagonist function

  1. Evidence that diclofenac and celecoxib are thyroid hormone receptor beta antagonists.

    Science.gov (United States)

    Zloh, Mire; Perez-Diaz, Noelia; Tang, Leslie; Patel, Pryank; Mackenzie, Louise S

    2016-02-01

    Long term use of NSAIDs is linked to side effects such as gastric bleeding and myocardial infarction. Use of in silico methods and pharmacology to investigate the potential for NSAIDs diclofenac, celecoxib and naproxen to bind to nuclear receptors. In silico screening predicted that both diclofenac and celecoxib has the potential to bind to a number of different nuclear receptors; docking analysis confirmed a theoretical ability for diclofenac and celecoxib but not naproxen to bind to TRβ. Results from TRβ luciferase reporter assays confirmed that both diclofenac and celecoxib display TRβ antagonistic properties; celecoxib, IC50 3.6 × 10(-6)M, and diclofenac IC50 5.3 × 10(-6)M, comparable to the TRβ antagonist MLS (IC50 3.1 × 10(-6)M). In contrast naproxen, a cardio-sparing NSAID, lacked TRβ antagonist effects. In order to determine the effects of NSAIDs in whole organ in vitro, we used isometric wire myography to measure the changes to Triiodothyronine (T3) induced vasodilation of rat mesenteric arteries. Incubation of arteries in the presence of the TRβ antagonist MLS000389544 (10(-5)M), as well as diclofenac (10(-5)M) and celecoxib (10(-5)M) but not naproxen significantly inhibited T3 induced vasodilation compared to controls. These results highlight the benefits of computational chemistry methods used to retrospectively analyse well known drugs for side effects. Using in silico and in vitro methods we have shown that both celecoxib and diclofenac but not naproxen exhibit off-target TRβ antagonist behaviour, which may be linked to their detrimental side effects. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Similar efficacy from specific and non-specific mineralocorticoid receptor antagonist treatment of muscular dystrophy mice.

    Science.gov (United States)

    Lowe, Jeovanna; Floyd, Kyle T; Rastogi, Neha; Schultz, Eric J; Chadwick, Jessica A; Swager, Sarah A; Zins, Jonathan G; Kadakia, Feni K; Smart, Suzanne; Gomez-Sanchez, Elise P; Gomez-Sanchez, Celso E; Raman, Subha V; Janssen, Paul M L; Rafael-Fortney, Jill A

    2016-01-01

    Combined treatment with an angiotensin-converting enzyme inhibitor and a mineralocorticoid receptor (MR) antagonist improved cardiac and skeletal muscle function and pathology in a mouse model of Duchenne muscular dystrophy. MR is present in limb and respiratory skeletal muscles and functions as a steroid hormone receptor. The goals of the current study were to compare the efficacy of the specific MR antagonist eplerenone with the non-specific MR antagonist spironolactone, both in combination with the angiotensin-converting enzyme inhibitor lisinopril. Three groups of n=18 dystrophin-deficient, utrophin-haploinsufficient male mice were given chow containing: lisinopril plus spironolactone, lisinopril plus eplerenone, or no drug, from four to 20 weeks-of-age. Eighteen C57BL/10 male mice were used as wild-type controls. In vivo measurements included cardiac magnetic resonance imaging, conscious electrocardiography, and grip strength. From each mouse in the study, diaphragm, extensor digitorum longus , and cardiac papillary muscle force was measured ex vivo , followed by histological quantification of muscle damage in heart, diaphragm, quadriceps, and abdominal muscles. MR protein levels were also verified in treated muscles. Treatment with specific and non-specific MR antagonists did not result in any adverse effects to dystrophic skeletal muscles or heart. Both treatments resulted in similar functional and pathological improvements across a wide array of parameters. MR protein levels were not reduced by treatment. These data suggest that spironolactone and eplerenone show similar effects in dystrophic mice and support the clinical development of MR antagonists for treating skeletal muscles in Duchenne muscular dystrophy.

  3. Molecular imaging of neuroendocrine tumors using {sup 68}Ga-labeled peptides (Somatostatin receptor PET/CT); Molekulare Bildgebung neuroendokriner Tumoren mit {sup 68}Ga-markierten Peptiden (Somatostatinrezeptor-PET/CT)

    Energy Technology Data Exchange (ETDEWEB)

    Baum, R.P.; Prasad, V. [Zentralklinik Bad Berka GmbH (Germany). Klinik fuer Nuklearmedizin/PET-Zentrum; Hoersch, D. [Zentralklinik Bad Berka GmbH (Germany). Klinik fuer Innere Medizin, Gastroenterologie, Onkologie, Endokrionologie

    2009-06-15

    Receptor PET/CT using {sup 68}Ga-labeled somatostatin analogues (DOTA-NOC, DOTA-TOC or DOTA-TATE) enables the highly sensitive molecular imaging of neuroendocrine tumors (NETs) based on the expression of somatostatin receptors and even the detection of receptor subtypes. Our experience after more than 3000 studies shows that receptor PET/CT has a significantly higher tumor detection rate than conventional scintigraphy (even in SPECT/CT technique), and that tumor lesions can be very accurately localized. By calculating standardized uptake values (SUV) - which are reproducible and investigator-independent - patients can be selected for peptide receptor radiotherapy and also the course after therapy can be controlled. Receptor-PET/CT is the most sensitive imaging modality for the detection of unknown primary tumors (CUP syndrome), which is especially true for the detection of neuroendocrine tumors of the pancreas and small bowel; whole-body staging (''one stop shop'') as well as restaging and selection of patients for peptide receptor radiotherapy can be performed using a patient-friendly procedure (examination finished within one hour) exposing the patient to less radiation than whole-body CT scanning. The {sup 68}Ge/{sup 68}Ga generator has proved very reliable over the years - even in a hospital environment. The effective costs for {sup 68}Ga labeled somatostatin analogues might be less than for scintigraphic agents, provided a certain number of studies per year are performed. The development of new tumor-specific peptides as well as of other DOTA- or NOTA-coupled radiopharmaceuticals opens a new avenue into the future: finally, the {sup 68}Ga generator could play a similar important role for PET/CT as did the {sup 99m}Tc-Generator for conventional gamma camera imaging over the last decades. (orig.)

  4. Positron emission tomography study on pancreatic somatostatin receptors in normal and diabetic rats with {sup 68}Ga-DOTA-octreotide: A potential PET tracer for beta cell mass measurement

    Energy Technology Data Exchange (ETDEWEB)

    Sako, Takeo [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Division of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Hasegawa, Koki; Nishimura, Mie; Kanayama, Yousuke; Wada, Yasuhiro; Hayashinaka, Emi; Cui, Yilong; Kataoka, Yosky [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Senda, Michio [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Division of Molecular Imaging, Institute of Biomedical Research and Innovation, 2-2 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan); Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe, Hyogo 650-0017 (Japan); Watanabe, Yasuyoshi, E-mail: yywata@riken.jp [Division of Bio-function Dynamics Imaging, RIKEN Center for Life Science Technologies, 6-7-3 Minatojima-minamimachi, Chuo-ku, Kobe, Hyogo 650-0047 (Japan)

    2013-12-06

    Highlights: •PET images showed high uptake of {sup 68}Ga-DOTA-octreotide in the normal pancreas. •{sup 68}Ga-DOTA-octreotide specifically binds to somatostatin receptors in the pancreas. •The pancreatic uptake of {sup 68}Ga-DOTA-octreotide was decreased in the diabetic rats. •{sup 68}Ga-DOTA-octreotide could be a candidate PET probe to measure the beta cell mass. -- Abstract: Diabetes mellitus (DM) is a metabolic disorder characterized by hyperglycemia, and the loss or dysfunction of pancreatic beta cells has been reported before the appearance of clinical symptoms and hyperglycemia. To evaluate beta cell mass (BCM) for improving the detection and treatment of DM at earlier stages, we focused on somatostatin receptors that are highly expressed in the pancreatic beta cells, and developed a positron emission tomography (PET) probe derived from octreotide, a metabolically stable somatostatin analog. Octreotide was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA), a chelating agent, and labeled with {sup 68}Gallium ({sup 68}Ga). After intravenous injection of {sup 68}Ga-DOTA-octreotide, a 90-min emission scan of the abdomen was performed in normal and DM model rats. The PET studies showed that {sup 68}Ga-DOTA-octreotide radioactivity was highly accumulated in the pancreas of normal rats and that the pancreatic accumulation was significantly reduced in the rats administered with an excess amount of unlabeled octreotide or after treatment with streptozotocin, which was used for the chemical induction of DM in rats. These results were in good agreement with the ex vivo biodistribution data. These results indicated that the pancreatic accumulation of {sup 68}Ga-DOTA-octreotide represented specific binding to the somatostatin receptors and reflected BCM. Therefore, PET imaging with {sup 68}Ga-DOTA-octreotide could be a potential tool for evaluating BCM.

  5. Antagonist profile of ibodutant at the tachykinin NK2 receptor in guinea pig isolated bronchi.

    Science.gov (United States)

    Santicioli, Paolo; Meini, Stefania; Giuliani, Sandro; Lecci, Alessandro; Maggi, Carlo Alberto

    2013-10-24

    In this study we have characterized the pharmacological profile of the non-peptide tachykinin NK 2 receptor antagonist ibodutant (MEN15596) in guinea pig isolated main bronchi contractility. The antagonist potency of ibodutant was evaluated using the selective NK 2 receptor agonist [βAla 8 ]NKA(4-10)-mediated contractions of guinea pig isolated main bronchi. In this assay ibodutant (30, 100 and 300nM) induced a concentration-dependent rightward shift of the [βAla 8 ]NKA(4-10) concentration-response curves without affecting the maximal contractile effect. The analysis of the results yielded a Schild-plot linear regression with a slope not different from unity (0.95, 95% c.l. 0.65-1.25), thus indicating a surmountable behaviour. The calculated apparent antagonist potency as pK B value was 8.31±0.05. Ibodutant (0.3-100nM), produced a concentration-dependent inhibition of the nonadrenergic-noncholinergic (NANC) contractile response induced by electrical field stimulation (EFS) of intrinsic airway nerves in guinea pig isolated main bronchi. At the highest concentration tested (100nM) ibodutant almost abolished the EFS-induced bronchoconstriction (95±4% inhibition), the calculated IC 50 value was 2.98nM (95% c.l. 1.73-5.16nM). In bronchi from ovalbumin (OVA) sensitized guinea pigs ibodutant (100nM) did not affect the maximal contractile response to OVA, but completely prevented the slowing in the fading of the motor response induced by phosphoramidon pretreatment linked to the endogenous neurokinin A release. Altogether, the present study demonstrate that ibodutant is a potent NK 2 receptor antagonist in guinea pig airways. © 2013 Published by Elsevier B.V.

  6. Antidepressant activity of nociceptin/orphanin FQ receptor antagonists in the mouse learned helplessness.

    Science.gov (United States)

    Holanda, Victor A D; Medeiros, Iris U; Asth, Laila; Guerrini, Remo; Calo', Girolamo; Gavioli, Elaine C

    2016-07-01

    Pharmacological and genetic evidence support antidepressant-like effects elicited by the blockade of the NOP receptor. The learned helplessness (LH) model employs uncontrollable and unpredictable electric footshocks as a stressor stimulus to induce a depressive-like phenotype that can be reversed by classical antidepressants. The present study aimed to evaluate the action of NOP receptor antagonists in helpless mice. Male Swiss mice were subjected to the three steps of the LH paradigm (i.e., (1) induction, (2) screening, and (3) test). Only helpless animals were subjected to the test session. During the test session, animals were placed in the electrified chamber and the latency to escape after the footshock and the frequency of escape failures were recorded. The effect of the following treatments administered before the test session were evaluated: nortriptyline (30 mg/kg, ip, 60 min), fluoxetine (30 mg/kg, ip, four consecutive days of treatment), and NOP antagonists SB-612111 (1-10 mg/kg, ip, 30 min) and UFP-101 (1-10 nmol, icv, 5 min). To rule out possible biases, the effects of treatments on controllable stressful and non stressful situations were assessed. In helpless mice, nortriptyline, fluoxetine, UFP-101 (3-10 nmol), and SB-612111 (3-10 mg/kg) significantly reduced escape latencies and escape failures. No effects of drug treatments were observed in mice subjected to the controllable electric footshocks and non stressful situations. Acute treatment with NOP antagonists reversed helplessness similarly to the classical antidepressants. These findings support the proposal that NOP receptor antagonists are worthy of development as innovative antidepressant drugs.

  7. Nonpeptidic urotensin-II receptor antagonists I: in vitro pharmacological characterization of SB-706375

    Science.gov (United States)

    Douglas, Stephen A; Behm, David J; Aiyar, Nambi V; Naselsky, Diane; Disa, Jyoti; Brooks, David P; Ohlstein, Eliot H; Gleason, John G; Sarau, Henry M; Foley, James J; Buckley, Peter T; Schmidt, Dulcie B; Wixted, William E; Widdowson, Katherine; Riley, Graham; Jin, Jian; Gallagher, Timothy F; Schmidt, Stanley J; Ridgers, Lance; Christmann, Lisa T; Keenan, Richard M; Knight, Steven D; Dhanak, Dashyant

    2005-01-01

    SB-706375 potently inhibited [125I]hU-II binding to both mammalian recombinant and ‘native' UT receptors (Ki 4.7±1.5 to 20.7±3.6 nM at rodent, feline and primate recombinant UT receptors and Ki 5.4±0.4 nM at the endogenous UT receptor in SJRH30 cells). Prior exposure to SB-706375 (1 μM, 30 min) did not alter [125I]hU-II binding affinity or density in recombinant cells (KD 3.1±0.4 vs 5.8±0.9 nM and Bmax 3.1±1.0 vs 2.8±0.8 pmol mg−1) consistent with a reversible mode of action. The novel, nonpeptidic radioligand [3H]SB-657510, a close analogue of SB-706375, bound to the monkey UT receptor (KD 2.6±0.4 nM, Bmax 0.86±0.12 pmol mg−1) in a manner that was inhibited by both U-II isopeptides and SB-706375 (Ki 4.6±1.4 to 17.6±5.4 nM) consistent with the sulphonamides and native U-II ligands sharing a common UT receptor binding domain. SB-706375 was a potent, competitive hU-II antagonist across species with pKb 7.29–8.00 in HEK293-UT receptor cells (inhibition of [Ca2+]i-mobilization) and pKb 7.47 in rat isolated aorta (inhibition of contraction). SB-706375 also reversed tone established in the rat aorta by prior exposure to hU-II (Kapp∼20 nM). SB-706375 was a selective U-II antagonist with ⩾100-fold selectivity for the human UT receptor compared to 86 distinct receptors, ion channels, enzymes, transporters and nuclear hormones (Ki/IC50>1 μM). Accordingly, the contractile responses induced in isolated aortae by KCl, phenylephrine, angiotensin II and endothelin-1 were unaltered by SB-706375 (1 μM). In summary, SB-706375 is a high-affinity, surmountable, reversible and selective nonpeptide UT receptor antagonist with cross-species activity that will assist in delineating the pathophysiological actions of U-II in mammals. PMID:15852036

  8. Effect of GABA receptor agonists or antagonists injected spinally on the blood glucose level in mice.

    Science.gov (United States)

    Sim, Yun-Beom; Park, Soo-Hyun; Kang, Yu-Jung; Kim, Sung-Su; Kim, Chea-Ha; Kim, Su-Jin; Jung, Jun-Sub; Ryu, Ohk-Hyun; Choi, Moon-Gi; Suh, Hong-Won

    2013-05-01

    The possible roles of gamma-amino butyric acid (GABA) receptors located in the spinal cord for the regulation of the blood glucose level were studied in ICR mice. We found in the present study that intrathecal (i.t.) injection with baclofen (a GABAB receptor agonist; 1-10 μg/5 μl) or bicuculline (a GABAA receptor antagonist; 1-10 μg/5 μl) caused an elevation of the blood glucose level in a dose-dependent manner. The hyperglycemic effect induced by baclofen was more pronounced than that induced by bicuculline. However, muscimol (a GABAA receptor agonist; 1-5 μg/5 μl) or phaclofen (a GABAB receptor antagonist; 5-10 μg/5 μl) administered i.t. did not affect the blood glucose level. Baclofen-induced elevation of the blood glucose was dose-dependently attenuated by phaclofen. Furthermore, i.t. pretreatment with pertussis toxin (PTX; 0.05 or 0.1 μg/5 μl) for 6 days dose-dependently reduced the hyperglycemic effect induced by baclofen. Our results suggest that GABAB receptors located in the spinal cord play important roles for the elevation of the blood glucose level. Spinally located PTX-sensitive G-proteins appear to be involved in hyperglycemic effect induced by baclofen. Furthermore, inactivation of GABAA receptors located in the spinal cord appears to be responsible for tonic up-regulation of the blood glucose level.

  9. Structure of CC chemokine receptor 2 with orthosteric and allosteric antagonists

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Yi; Qin, Ling; Ortiz Zacarías, Natalia V.; de Vries, Henk; Han, Gye Won; Gustavsson, Martin; Dabros, Marta; Zhao, Chunxia; Cherney, Robert J.; Carter, Percy; Stamos, Dean; Abagyan, Ruben; Cherezov, Vadim; Stevens, Raymond C.; IJzerman, Adriaan P.; Heitman, Laura H.; Tebben, Andrew; Kufareva, Irina; Handel , Tracy M. (Vertex Pharm); (Leiden-MC); (USC); (BMS); (UCSD)

    2016-12-07

    CC chemokine receptor 2 (CCR2) is one of 19 members of the chemokine receptor subfamily of human class A G-protein-coupled receptors. CCR2 is expressed on monocytes, immature dendritic cells, and T-cell subpopulations, and mediates their migration towards endogenous CC chemokine ligands such as CCL2 (ref. 1). CCR2 and its ligands are implicated in numerous inflammatory and neurodegenerative diseases2 including atherosclerosis, multiple sclerosis, asthma, neuropathic pain, and diabetic nephropathy, as well as cancer3. These disease associations have motivated numerous preclinical studies and clinical trials4 (see http://www.clinicaltrials.gov) in search of therapies that target the CCR2–chemokine axis. To aid drug discovery efforts5, here we solve a structure of CCR2 in a ternary complex with an orthosteric (BMS-681 (ref. 6)) and allosteric (CCR2-RA-[R]7) antagonist. BMS-681 inhibits chemokine binding by occupying the orthosteric pocket of the receptor in a previously unseen binding mode. CCR2-RA-[R] binds in a novel, highly druggable pocket that is the most intracellular allosteric site observed in class A G-protein-coupled receptors so far; this site spatially overlaps the G-protein-binding site in homologous receptors. CCR2-RA-[R] inhibits CCR2 non-competitively by blocking activation-associated conformational changes and formation of the G-protein-binding interface. The conformational signature of the conserved microswitch residues observed in double-antagonist-bound CCR2 resembles the most inactive G-protein-coupled receptor structures solved so far. Like other protein–protein interactions, receptor–chemokine complexes are considered challenging therapeutic targets for small molecules, and the present structure suggests diverse pocket epitopes that can be exploited to overcome obstacles in drug design.

  10. ``In silico'' study of the binding of two novel antagonists to the nociceptin receptor

    Science.gov (United States)

    Della Longa, Stefano; Arcovito, Alessandro

    2018-02-01

    Antagonists of the nociceptin receptor (NOP) are raising interest for their possible clinical use as antidepressant drugs. Recently, the structure of NOP in complex with some piperidine-based antagonists has been revealed by X-ray crystallography. In this study, a multi-flexible docking (MF-docking) procedure, i.e. docking to multiple receptor conformations extracted by preliminary molecular dynamics trajectories, together with hybrid quantum mechanics/molecular mechanics (QM/MM) simulations have been carried out to provide the binding mode of two novel NOP antagonists, one of them selective (BTRX-246040, formerly named LY-2940094) and one non selective (AT-076), i.e. able to inactivate NOP as well as the classical µ- k- and δ-opioid receptors (MOP KOP and DOP). According to our results, the pivotal role of residue D1303,32 (upper indexes are Ballesteros-Weinstein notations) is analogous to that enlighten by the already known X-ray structures of opioid receptors: binding of the molecules are predicted to require a slight readjustment of the hydrophobic pocket (residues Y1313,33, M1343,36, I2195,43, Q2806,52 and V2836,55) in the orthosteric site of NOP, accommodating either the pyridine-pyrazole (BTRX-246040) or the isoquinoline (AT-076) moiety of the ligand, in turn allowing the protonated piperidine nitrogen to maximize interaction (salt-bridge) with residue D1303,32 of the NOP, and the aromatic head to be sandwiched in optimal π-stacking between Y1313,33 and M1343,36. The QM/MM optimization after the MF-docking procedure has provided the more likely conformations for the binding to the NOP receptor of BTRX-246040 and AT-076, based on different pharmacophores and exhibiting different selectivity profiles. While the high selectivity for NOP of BTRX-246040 can be explained by interactions with NOP specific residues, the lack of selectivity of AT-076 could be associated to its ability to penetrate into the deep hydrophobic pocket of NOP, while retaining a

  11. Stereochemistry of quinoxaline antagonist binding to a glutamate receptor investigated by Fourier transform infrared spectroscopy.

    Science.gov (United States)

    Madden, D R; Thiran, S; Zimmermann, H; Romm, J; Jayaraman, V

    2001-10-12

    The stereochemistry of the interactions between quinoxaline antagonists and the ligand-binding domain of the glutamate receptor 4 (GluR4) have been investigated by probing their vibrational modes using Fourier transform infrared spectroscopy. In solution, the electron-withdrawing nitro groups of both compounds establish a resonance equilibrium that appears to stabilize the keto form of one of the cyclic amide carbonyl bonds. Changes in the 6,7-dinitro-2,3-dihydroxyquinoxaline vibrational spectra on binding to the glutamate receptor, interpreted within the framework of a published crystal structure, illuminate the stereochemistry of the interaction and suggest that the binding site imposes a more polarized electronic bonding configuration on this antagonist. Similar spectral changes are observed for 6-cyano-7-dinitro-2,3-dihydroxyquinoxaline, confirming that its interactions with the binding site are highly similar to those of 6,7-dinitro-2,3-dihydroxyquinoxaline and leading to a model of the 6-cyano-7-dinitro-2,3-dihydroxyquinoxaline-S1S2 complex, for which no crystal structure is available. Conformational changes within the GluR ligand binding domain were also monitored. Compared with the previously reported spectral changes seen on binding of the agonist glutamate, only a relatively small change is detected on antagonist binding. This correlation between the functional effects of different classes of ligand and the magnitude of the spectroscopic changes they induce suggests that the spectral data reflect physiologically relevant conformational processes.

  12. Quantitative Assessment of 99mTc-Depreotide Uptake in Oesophageal Cancer and Precursor Conditions and Its Reflection in Immunohistochemically Detected Somatostatin Receptors

    International Nuclear Information System (INIS)

    Herlin, G.; Aspelin, P.; Axelsson, R.; Herlin, G.; Aspelin, P.; Axelsson, R.; Lundell, L.; Ost, A.; Svensson, L.

    2012-01-01

    Background. Somatostatin receptors (SSTRs) are over-expressed in several tumors making it possible for imaging with labelled SSTR. A previous study showed feasibility to image oesophageal cancer with SSTR analogue 99m Tc-depreotide. Purpose. (1) To investigate expression of the SSTRs in different types of esophageal carcinoma and (2) to correlate such an expression with 99m Tc-depreotide uptake in these lesions. Material and Methods. Total 28 patients (17 with esophageal cancer and 11 with Barrett’s esophagus) were examined with 99m Tc-depreotide scintigraphy. The SSTR2A, SSTR2B, SSTR3, and SSTR5 were analyzed immunohistochemically in the lesion samples. Results. Among the patients with adenocarcinoma 10/11 expressed different amounts of SSTRs, while SSTRs were absent in 5/6 patients with Squamous cell carcinoma (Sqcc). There was no correlation neither between the 99m Tc-depreotide uptake and the amount of SSTRs nor between the amount of SSTRs and differentiation grade of the tumor. Conclusions. (1) SSTRs are expressed in esophageal carcinoma and more abundantly so in adenocancer specimens; (2) in vivo 99m Tc-depreotide uptake does not obviously correlate with the immunohistochemically detection of SSTRs of different subtypes in esophageal carcinoma.

  13. Quantitative Assessment of 99mTc-Depreotide Uptake in Oesophageal Cancer and Precursor Conditions and Its Reflection in Immunohistochemically Detected Somatostatin Receptors

    International Nuclear Information System (INIS)

    Herlin, Gunnar; Lundell, Lars; Öst, Åke; Aspelin, Peter; Svensson, Leif; Axelsson, Rimma

    2012-01-01

    Background. Somatostatin receptors (SSTRs) are over-expressed in several tumors making it possible for imaging with labelled SSTR. A previous study showed feasibility to image oesophageal cancer with SSTR analogue 99m Tc-depreotide. Purpose. (1) To investigate expression of the SSTRs in different types of esophageal carcinoma and (2) to correlate such an expression with 99m Tc-depreotide uptake in these lesions. Material and Methods. Total 28 patients (17 with esophageal cancer and 11 with Barrett's esophagus) were examined with 99m Tc-depreotide scintigraphy. The SSTR2A, SSTR2B, SSTR3, and SSTR5 were analyzed immunohistochemically in the lesion samples. Results. Among the patients with adenocarcinoma 10/11 expressed different amounts of SSTRs, while SSTRs were absent in 5/6 patients with Squamous cell carcinoma (Sqcc). There was no correlation neither between the 99m Tc-depreotide uptake and the amount of SSTRs nor between the amount of SSTRs and differentiation grade of the tumor. Conclusions. (1) SSTRs are expressed in esophageal carcinoma and more abundantly so in adenocancer specimens; (2) in vivo 99m Tc-depreotide uptake does not obviously correlate with the immunohistochemically detection of SSTRs of different subtypes in esophageal carcinoma

  14. Peptide receptor radionuclide therapy (PRRT) of neuroendocrine tumors: First comparative results using the somatostatin analogues Lu-177 DOTA-NOC and Lu-177 DOTA-TATE

    International Nuclear Information System (INIS)

    Wehrmann, C.; Senftleben, S.; Baum, R.P.

    2005-01-01

    Peptide receptor radionuclide therapy (PRRT) is used in our department since 5 years (approx. 400 applications) for the treatment of patients with metastatic neuroendocrine tumors. Of all known peptides, the somatostatin analogue DOTA-NOC shows in vitro the highest affinity to somatostatin receptors (sstr) 3 and 5 and a very high affinity to sstr 2. We studied the in vivo behaviour of the two peptides DOTA-NOC and DOTA-TATE (highest affinity to sstr 2) by the use of different parameters like tumor and organ uptake, effective half-lifes (kinetics) and mean absorbed organ and tumor doses. We studied 27 patients with metastatic neuroendocrine tumors with high somatostatin expression, as verified prior to treatment by Ga-68 DOTA-NOC receptor PET/CT or somatostatin receptor scintigraphy (Tc-99m EDDA-Hynic TOC or In-111 OctreoScan, planar and SPECT). 22 patients (8M and 14F; aged 619 years) were treated with 2500 6790 MBq Lu-177 DOTA-TATE. Another 5 patients (1M and 4F, aged 6310 years) were treated with 4000 7400 MBq Lu-177 DOTA-NOC. Labelling efficiency and radiochemical purity using Lutetium-177 chloride (obtained from PerkinElmer Life Sciences, USA) were constantly over 99.5%. Whole-body scans (anterior/posterior) were performed at 0.5h, 3h, 24h, 48h, 72h and 96h p.i. ROIs were drawn over the whole-body, organs, and different metastases (mainly in the liver). Blood samples were obtained in 12 patients after therapy with Lu-177 DOTA-TATE over 5 days for calculating the kinetics in blood. The ROI results were used to determine the uptake and effective half-life in different organs (kidney, spleen, liver, bone etc.) and the tumor residence times. By means of geometric mean, and after background correction, the ROI results were also used to calculate the estimated absorbed organ and tumor doses using the OLINDA software. Compared to Lu-177 DOTA-TATE (=100%), the uptake of Lu-177 DOTA-NOC was higher for the whole-body (45%) and for normal tissues (28%), and also in the

  15. [111In-DOTA]LTT-SS28, a first pansomatostatin radioligand for in vivo targeting of somatostatin receptor-positive tumors.

    Science.gov (United States)

    Maina, Theodosia; Cescato, Renzo; Waser, Beatrice; Tatsi, Aikaterini; Kaloudi, Aikaterini; Krenning, Eric P; de Jong, Marion; Nock, Berthold A; Reubi, Jean Claude

    2014-08-14

    Radiolabeled pansomatostatin-like analogues are expected to enhance the diagnostic sensitivity and to expand the clinical indications of currently applied sst2-specific radioligands. In this study, we present the somatostatin mimic [DOTA]LTT-SS28 {[(DOTA)Ser1,Leu8,D-Trp22,Tyr25]SS28} and its 111In radioligand. [DOTA]LTT-SS28 exhibited a pansomatostatin-like profile binding with high affinity to all five hsst1-hsst5 subtypes (IC50 values in the lower nanomolar range). Furthermore, [DOTA]LTT-SS28 behaved as an agonist at hsst2, hsst3, and hsst5, efficiently stimulating internalization of the three receptor subtypes. Radioligand [111In-DOTA]LTT-SS28 showed good stability in the mouse bloodstream. It displayed strong and specific uptake in AR42J tumors 4 h postinjection (9.3±1.6% ID/g vs 0.3±0.0% ID/g during sst2 blockade) in mice. Significant and specific uptake was also observed in HEK293-hsst2-, HEK293-hsst3-, and HEK293-hsst5-expressing tumors (4.43±1.5, 4.88±1.1, and DOTA]LTT-SS28 specifically localizes in sst2-, sst3-, and sst5-expressing xenografts in mice showing promise for multi-sst1-sst5 targeted tumor imaging.

  16. Altered Expression of Somatostatin Receptors in Pancreatic Islets from NOD Mice Cultured at Different Glucose Concentrations In Vitro and in Islets Transplanted to Diabetic NOD Mice In Vivo

    Directory of Open Access Journals (Sweden)

    Eva Ludvigsen

    2011-01-01

    Full Text Available Somatostatin acts via five receptors (sst1-5. We investigated if the changes in pancreatic islet sst expression in diabetic NOD mice compared to normoglycemic mice are a consequence of hyperglycemia or the ongoing immune reaction in the pancreas. Pancreatic islets were isolated from NOD mice precultured for 5 days and further cultured for 3 days at high or low glucose before examined. Islets were also isolated from NOD mice and transplanted to normal or diabetic mice in a number not sufficient to cure hyperglycemia. After three days, the transplants were removed and stained for sst1-5 and islet hormones. Overall, changes in sst islet cell expression were more common in islets cultured in high glucose concentration in vitro as compared to the islet transplantation in vivo to diabetic mice. The beta and PP cells exhibited more frequent changes in sst expression, while the alpha and delta cells were relatively unaffected by the high glucose condition. Our findings suggest that the glucose level may alter sst expressed in islets cells; however, immune mechanisms may counteract such changes in islet sst expression.

  17. CRF receptor antagonist astressin-B reverses and prevents alopecia in CRF over-expressing mice.

    Directory of Open Access Journals (Sweden)

    Lixin Wang

    2011-02-01

    Full Text Available Corticotropin-releasing factor (CRF signaling pathways are involved in the stress response, and there is growing evidence supporting hair growth inhibition of murine hair follicle in vivo upon stress exposure. We investigated whether the blockade of CRF receptors influences the development of hair loss in CRF over-expressing (OE-mice that display phenotypes of Cushing's syndrome and chronic stress, including alopecia. The non-selective CRF receptors antagonist, astressin-B (5 µg/mouse injected peripherally once a day for 5 days in 4-9 months old CRF-OE alopecic mice induced pigmentation and hair re-growth that was largely retained for over 4 months. In young CRF-OE mice, astressin-B prevented the development of alopecia that occurred in saline-treated mice. Histological examination indicated that alopecic CRF-OE mice had hair follicle atrophy and that astressin-B revived the hair follicle from the telogen to anagen phase. However, astressin-B did not show any effect on the elevated plasma corticosterone levels and the increased weights of adrenal glands and visceral fat in CRF-OE mice. The selective CRF₂ receptor antagonist, astressin₂-B had moderate effect on pigmentation, but not on hair re-growth. The commercial drug for alopecia, minoxidil only showed partial effect on hair re-growth. These data support the existence of a key molecular switching mechanism triggered by blocking peripheral CRF receptors with an antagonist to reset hair growth in a mouse model of alopecia associated with chronic stress.

  18. Effects of NMDA receptor antagonists on probability discounting depend on the order of probability presentation.

    Science.gov (United States)

    Yates, Justin R; Breitenstein, Kerry A; Gunkel, Benjamin T; Hughes, Mallory N; Johnson, Anthony B; Rogers, Katherine K; Shape, Sara M

    Risky decision making can be measured using a probability-discounting procedure, in which animals choose between a small, certain reinforcer and a large, uncertain reinforcer. Recent evidence has identified glutamate as a mediator of risky decision making, as blocking the N-methyl-d-aspartate (NMDA) receptor with MK-801 increases preference for a large, uncertain reinforcer. Because the order in which probabilities associated with the large reinforcer can modulate the effects of drugs on choice, the current study determined if NMDA receptor ligands alter probability discounting using ascending and descending schedules. Sixteen rats were trained in a probability-discounting procedure in which the odds against obtaining the large reinforcer increased (n=8) or decreased (n=8) across blocks of trials. Following behavioral training, rats received treatments of the NMDA receptor ligands MK-801 (uncompetitive antagonist; 0, 0.003, 0.01, or 0.03mg/kg), ketamine (uncompetitive antagonist; 0, 1.0, 5.0, or 10.0mg/kg), and ifenprodil (NR2B-selective non-competitive antagonist; 0, 1.0, 3.0, or 10.0mg/kg). Results showed discounting was steeper (indicating increased risk aversion) for rats on an ascending schedule relative to rats on the descending schedule. Furthermore, the effects of MK-801, ketamine, and ifenprodil on discounting were dependent on the schedule used. Specifically, the highest dose of each drug decreased risk taking in rats in the descending schedule, but only MK-801 (0.03mg/kg) increased risk taking in rats on an ascending schedule. These results show that probability presentation order modulates the effects of NMDA receptor ligands on risky decision making. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. An intrapatient comparison of 99mTc-EDDA/HYNIC-TOC with 111In-DTPA-octreotide for diagnosis of somatostatin receptor-expressing tumors.

    Science.gov (United States)

    Gabriel, Michael; Decristoforo, Clemens; Donnemiller, Eveline; Ulmer, Hanno; Watfah Rychlinski, Christine; Mather, Stephen J; Moncayo, Roy

    2003-05-01

    The aim of this study was to compare the imaging abilities of the recently developed somatostatin analog, (99m)Tc-hydrazinonicotinyl-Tyr(3)-octreotide ((99m)Tc-HYNIC-TOC [(99m)Tc-TOC]), with (111)In-diethylenediaminepentaacetic acid-D-Phe(1)-octreotide ((111)In-OCT [Octreoscan]) in patients undergoing routine somatostatin receptor (SSTR) scintigraphy. Forty-one patients (20 men, 21 women; age range, 29-75 y; mean age, 56.7 y) with either histologically proven or biologically and clinically suspected endocrine tumors were enrolled in the study. Four groups were distinguished: (a) patients being evaluated for the detection and localization of neuroendocrine tumors (n = 6), (b) tumor staging (n = 19), (c) patients being investigated to determine the SSTR status of tumor lesions (n = 11), and (d) patient follow-up studies (n = 5). Each patient received a mean activity of 150 MBq (111)In-OCT and 350-400 MBq (99m)Tc-TOC. Scintigraphy with (99m)Tc-TOC was performed 4 h after injection and scintigraphy with (111)In-OCT was performed 4 and 24 h after injection. SPECT studies of areas of interest were performed 4 h after injection for both tracers as well as at 24 h after injection for (111)In-OCT. The time interval between the studies using each tracer ranged from 2 to 22 d (mean interval, 9.3 d). (111)In-OCT and (99m)Tc-TOC showed an equivalent scan result in 32 patients (78%), 9 cases showed discrepancies (22%), false-negative results with (111)In-OCT were seen in 6 cases (14.6%), whereas (99m)Tc-TOC was false-positive in 2 cases (4.9%). (111)In-OCT was true-negative in both cases. The false-positive findings of the (99m)Tc-TOC studies were caused by nonspecific uptake in the bowel. In 1 case, (99m)Tc-TOC correctly identified a metastasis in the lumbar spine but both scan results were false-positive because of an inflammatory process. In 21 patients with SSTR-expressing tumors, the semiquantitative region-of-interest analysis showed that (99m)Tc-TOC achieved higher tumor

  20. Design, Synthesis, and Biological Evaluation of 68Ga-DOTA-PA1 for Lung Cancer: A Novel PET Tracer for Multiple Somatostatin Receptor Imaging.

    Science.gov (United States)

    Liu, Fei; Liu, Teli; Xu, Xiaoxia; Guo, Xiaoyi; Li, Nan; Xiong, Chiyi; Li, Chun; Zhu, Hua; Yang, Zhi

    2018-02-05

    Most of the radiolabeled somatostatin analogues (SSAs) are specific for subtype somatostatin receptor 2 (SSTR 2 ). Lack of ligands targeting other subtypes of SSTRs, especially SSTR 1, SSTR 3 , and SSTR 5 , limited their applications in tumors of low SSTR 2 expression, including lung tumor. In this study, we aimed to design and synthesize a positron emission tomography (PET) radiotracer targeting multi-subtypes of SSTRs for PET imaging. PA1 peptide and its conjugate with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) chelator or fluorescein isothiocyanate (FITC) at the N-terminal of the lysine position were synthesized. 68 Ga was chelated to DOTA-PA1 to obtain 68 Ga-DOTA-PA1 radiotracer. The stability, lipophilicity, binding affinity, and binding specificity of 68 Ga-DOTA-PA1 and FITC-PA1 were evaluated by various in vitro experiments. Micro-PET imaging of 68 Ga-DOTA-PA1 was performed in nude mice bearing A549 lung adenocarcinoma, as compared with 68 Ga-DOTA-(Tyr3)-octreotate ( 68 Ga-DOTA-TATE). Histological analysis of SSTR expression in A549 tumor tissues and human tumor tissues was conducted using immunofluorescence staining and immunohistochemical assay. 68 Ga-DOTA-PA1 had high radiochemical yield and radiochemical purity of over 95% and 99%, respectively. The radiotracer was stable in vitro in different buffers over a 2 h incubation period. Cell uptake of 68 Ga-DOTA-PA1 was 1.31-, 1.33-, and 1.90-fold that of 68 Ga-DOTA-TATE, which has high binding affinity only for SSTR 2 , after 2 h incubation in H520, PG, and A549 lung cancer cell lines, respectively. Micro-PET images of 68 Ga-DOTA-PA1 showed that the PET imaging signal correlated with the total expression of SSTRs, instead of SSTR 2 only, which was measured by Western blotting and immunofluorescence analysis in mice bearing A549 tumors. In summary, a novel PET radiotracer, 68 Ga-DOTA-PA1, targeting multi-subtypes of SSTRs, was successfully synthesized and was confirmed to be useful for PET

  1. Modification of Anxious Behavior after Psychogenic Trauma and Treatment with Galanin Receptor Antagonist.

    Science.gov (United States)

    Lyudyno, V I; Tsikunov, S G; Abdurasulova, I N; Kusov, A G; Klimenko, V M

    2015-07-01

    Effects of blockage of central galanin receptors on anxiety manifestations were studied in rats with psychogenic trauma. Psychogenic trauma was modeled by exposure of a group of rats to the situation when the partner was killed by a predator. Antagonist of galanin receptors was intranasally administered before stress exposure. Animal behavior was evaluated using the elevated-plus maze test, free exploratory paradigm, and open-field test. Psychogenic trauma was followed by an increase in anxiety level and appearance of agitated behavior. Blockage of galanin receptors aggravated behavioral impairment, which manifested in the pathological anxious reactions - manifestations of hypervigilance and hyperawareness. The results suggest that endogenous pool of galanin is involved into prevention of excessive CNS response to stressful stimuli typical of posttraumatic stress disorder.

  2. Radiolabeling with fluorine-18 of a protein, interleukin-1 receptor antagonist

    Energy Technology Data Exchange (ETDEWEB)

    Prenant, C., E-mail: cprenant@cyclopharma.f [Wolfson Molecular Imaging Centre, University of Manchester, Manchester (United Kingdom); Cawthorne, C. [Academic Department of Radiation Oncology, Christie NHS Foundation Trust, Manchester (United Kingdom); Fairclough, M. [Wolfson Molecular Imaging Centre, University of Manchester, Manchester (United Kingdom); Rothwell, N.; Boutin, H. [Faculty of Life Sciences, University of Manchester, Manchester (United Kingdom)

    2010-09-15

    IL-1RA is a naturally occurring antagonist of the pro-inflammatory cytokine interleukin-1 (IL-1) with high therapeutic promise, but its pharmacokinetic remains poorly documented. In this report, we describe the radiolabeling of recombinant human interleukin-1 receptor antagonist (rhIL-1RA) with fluorine-18 to allow pharmacokinetic studies by positron emission tomography (PET). rhIL-1RA was labeled randomly by reductive alkylation of free amino groups (the {epsilon}-amino group of lysine residues or amino-terminal residues) using [{sup 18}F]fluoroacetaldehyde under mild reaction conditions. Radiosyntheses used a remotely controlled experimental rig within 100 min and the radiochemical yield was in the range 7.1-24.2% (decay corrected, based on seventeen syntheses). We showed that the produced [{sup 18}F]fluoroethyl-rhIL-1ra retained binding specificity by conducting an assay on rat brain sections, allowing its pharmakokinetic study using PET.

  3. Dynamics of urokinase receptor interaction with Peptide antagonists studied by amide hydrogen exchange and mass spectrometry

    DEFF Research Database (Denmark)

    Jørgensen, Thomas J D; Gårdsvoll, Henrik; Danø, Keld

    2004-01-01

    Using amide hydrogen exchange combined with electrospray ionization mass spectrometry, we have in this study determined the number of amide hydrogens on several peptides that become solvent-inaccessible as a result of their high-affinity interaction with the urokinase-type plasminogen activator...... receptor (uPAR). These experiments reveal that at least six out of eight amide hydrogens in a synthetic nine-mer peptide antagonist (AE105) become sequestered upon engagement in uPAR binding. Various uPAR mutants with decreased affinity for this peptide antagonist gave similar results, thereby indicating...... that deletion of the favorable interactions involving the side chains of these residues in uPAR does not affect the number of hydrogen bonds established by the main chain of the peptide ligand. The isolated growth factor-like domain (GFD) of the cognate serine protease ligand for uPAR showed 11 protected amide...

  4. 125I-labeled 8-phenylxanthine derivatives: antagonist radioligands for adenosine A1 receptors

    International Nuclear Information System (INIS)

    Linden, J.; Patel, A.; Earl, C.Q.; Craig, R.H.; Daluge, S.M.

    1988-01-01

    A series of 8-phenylxanthine derivatives has been synthesized with oxyacetic acid on the para phenyl position to increase aqueous solubility and minimize nonspecific binding and iodinatable groups on the 1- or 3-position of the xanthine ring. The structure-activity relationship for binding of these compounds to A1 adenosine receptors of bovine and rat brain and A2 receptors of human platelets was examined. The addition of arylamine or photosensitive aryl azide groups to the 3-position of xanthine had little effect on A1 binding affinity with or without iodination, whereas substitutions at the 1-position caused greatly reduced A1 binding affinity. The addition of an aminobenzyl group to the 3-position of the xanthine had little effect on A2 binding affinity, but 3-aminophenethyl substitution decreased A2 binding affinity. Two acidic 3-(arylamino)-8-phenylxanthine derivatives were labeled with 125 I and evaluated as A1 receptor radioligands. The new radioligands bound to A1 receptors with KD values of 1-1.25 nM. Specific binding represented over 80% of total binding. High concentrations of NaCl or other salts increased the binding affinity of acidic but not neutral antagonists, suggesting that interactions between ionized xanthines and receptors may be affected significantly by changes in ionic strength. On the basis of binding studies with these antagonists and isotope dilution with the agonist [ 125 I]N6-(4-amino-3-iodobenzyl)adenosine, multiple agonist affinity states of A1 receptors have been identified

  5. The somatostatin receptor-targeted radiotherapeutic [{sup 90}Y-DOTA-dPhe{sup 1},Tyr{sup 3}]octreotide ({sup 90}Y-SMT 487) eradicates experimental rat pancreatic CA 20948 tumours

    Energy Technology Data Exchange (ETDEWEB)

    Stolz, B.; Weckbecker, G.; Smith-Jones, P.M.; Albert, R.; Raulf, F.; Bruns, C. [Novartis Pharma AG, Basel (Switzerland)

    1998-07-01

    Somatostatin receptor-expressing tumours are potential targets for therapy with radiolabelled somatostatin analogues. We have synthesized a number of such analogues in the past and identified [DOTA-dPhe{sup 1}, Tyr{sup 3}]octreotide (SMT 487) as the most promising candidate molecule because of its advantageous properties in cellular and in vivo tumour models. In the current paper we describe the radiotherapeutic effect of yttrium-90 labelled SMT 487 in Lewis rats bearing the somatostatin receptor-positive rat pancreatic tumour CA 20948. SMT 487 binds with nanomolar affinity to both the human and the rat somatostatin receptor subtype 2 (sst{sub 2}) (human sst{sub 2} IC{sub 50}=0.9 nM, rat sst{sub 2} IC{sub 50}=0.5 nM). In vivo, {sup 90}Y-SMT 487 distributed rapidly to the sst{sub 2} expressing CA 20948 rat pancreatic tumour, with a tumour-to-blood ratio of 49.15 at 24 h post injection. A single intravenous administration of 10 mCi/kg {sup 90}Y-SMT 487 resulted in a complete remission of the tumours in five out of seven CA 20948 tumour-bearing Lewis rats. No regrowth of the tumours occurred 8 months post injection. Control animals that were treated with 30 {mu}g/kg of unlabelled SMT 487 had to be sacrificed 10 days post injection due to excessive growth or necrotic areas on the tumour surface. Upon re-inoculation of tumour cells into those rats that had shown complete remission, the tumours disappeared after 3-4 weeks of moderate growth without any further treatment. The present study shows for the first time the curative potential of {sup 90}Y-SMT 487-based radiotherapy for somatostatin receptor-expressing tumours. Clinical phase I studies with yttrium-labelled SMT 487 have started in September 1997. (orig.) With 4 figs., 2 tabs., 29 refs.

  6. Potent and long-acting corticotropin releasing factor (CRF) receptor 2 selective peptide competitive antagonists.

    Science.gov (United States)

    Rivier, J; Gulyas, J; Kirby, D; Low, W; Perrin, M H; Kunitake, K; DiGruccio, M; Vaughan, J; Reubi, J C; Waser, B; Koerber, S C; Martinez, V; Wang, L; Taché, Y; Vale, W

    2002-10-10

    We present evidence that members of the corticotropin releasing factor (CRF) family assume distinct structures when interacting with the CRF(1) and CRF(2) receptors. Predictive methods, physicochemical measurements, and structure-activity relationship studies have suggested that CRF, its family members, and competitive antagonists such as astressin [cyclo(30-33)[DPhe(12),Nle(21),Glu(30),Lys(33),Nle(38)]hCRF((12-41))] assume an alpha-helical conformation when interacting with their receptors. We had shown that alpha-helical CRF((9-41)) and sauvagine showed some selectivity for CRF receptors other than that responsible for ACTH secretion(1) and later for CRF2.(2) More recently, we suggested the possibility of a helix-turn-helix motif around a turn encompassing residues 30-33(3) that would confer high affinity for both CRF(1) and CRF(2)(2,4) in agonists and antagonists of all members of the CRF family.(3) On the other hand, the substitutions that conferred ca. 100-fold CRF(2) selectivity to the antagonist antisauvagine-30 [[DPhe(11),His(12)]sauvagine((11-40))] did not confer such property to the corresponding N-terminally extended agonists. We find here that a Glu(32)-Lys(35) side chain to side chain covalent lactam constraint in hCRF and the corresponding Glu(31)-Lys(34) side chain to side chain covalent lactam constraint in sauvagine yield potent ligands that are selective for CRF(2). Additionally, we introduced deletions and substitutions known to increase duration of action to yield antagonists such as cyclo(31-34)[DPhe(11),His(12),C(alpha)MeLeu(13,39),Nle(17),Glu(31),Lys(34)]Ac-sauvagine((8-40)) (astressin(2)-B) with CRF(2) selectivities greater than 100-fold. CRF receptor autoradiography was performed in rat tissue known to express CRF(2) and CRF(1) in order to confirm that astressin(2)-B could indeed bind to established CRF(2) but not CRF(1) receptor-expressing tissues. Extended duration of action of astressin(2)-B vs that of antisauvagine-30 is demonstrated in

  7. Calcitonin gene-related peptide and somatostatin releases correlated with the area under the lafutidine concentration-time curve in human plasma.

    Science.gov (United States)

    Ikawa, K; Shimatani, T; Azuma, Y; Inoue, M; Morikawa, N

    2006-08-01

    To examine the effects of the histamine H(2)-receptor antagonist, lafutidine, at clinical dosage (10 mg tablet after a standardized meal) on plasma levels of the gastrointestinal peptides, calcitonin gene-related peptide (CGRP), somatostatin and gastrin. Six healthy male volunteers ate a standardized meal, and received either lafutidine orally at a dose of 10 mg or water only (control). Blood samples were taken before and up to 4 h after the drug administration. Plasma lafutidine concentrations were determined by high pressure liquid chromatography. Pharmacokinetic analysis of lafutidine was performed using one-compartmental model. The levels of immunoreactive substances of plasma CGRP, somatostatin and gastrin were measured by enzyme immunoassay, and the amount of peptide release was calculated by the trapezoidal method. Lafutidine significantly increased plasma CGRP levels at 1, 1.5, 2.5 and 4 h and the total amount of CGRP release (192 +/- 14.0 pg.h/mL) compared with the control group (128 +/- 21.5 pg.h/mL). Lafutidine significantly increased the plasma somatostatin levels at 1 and 1.5 h, and the total amount of somatostatin released (107 +/- 18.2 pg.h/mL) compared with the control (78.4 +/- 7.70 pg.h/mL). The area under the drug concentration-time curve (AUC) from 0 to 4 h after administration correlated well with the Delta-CGRP and Delta-somatostatin release but not with total amount of gastrin released. However, plasma gastrin levels were significantly elevated at 1.5 h after drug administration. Lafutidine at clinical dosage increases plasma CGRP and the somatostatin. The amounts released correlated with the AUC of lafutidine in humans. These results suggest that the increased release of CGRP and somatostatin may contribute to its gastroprotective and anti-acid secretory effect.

  8. Nonpeptide corticotropin-releasing hormone receptor type 1 antagonists and their applications in psychosomatic disorders.

    Science.gov (United States)

    Contoreggi, Carlo; Rice, Kenner C; Chrousos, George

    2004-01-01

    Overproduction of corticotropin-releasing hormone (CRH) and stress system abnormalities are seen in psychiatric diseases such as depression, anxiety, eating disorders, and addiction. Investigations of CRH type 1 receptor (CRHR1) nonpeptide antagonists suggest therapeutic potential for treatment of these and other neuropsychiatric diseases. However, overproduction of CRH in the brain and on its periphery and disruption of the hypothalamic-pituitary-adrenal axis are also found in 'somatic' disorders. Some rare forms of Cushing's disease and related pituitary/adrenal disorders are obvious applications for CRHR1 antagonists. In addition, however, these antagonists may also be effective in treating more common somatic diseases. Patients with obesity and metabolic syndrome who often have subtle, but chronic hypothalamic-pituitary-adrenal hyperactivity, which may reflect central dysregulation of CRH and consequently glucocorticoid hypersecretion, could possibly be treated by administration of CRHR1 antagonists. Hormonal, autonomic, and immune aberrations are also present in chronic inflammatory, autoimmune, and allergic diseases, with considerable evidence linking CRH with the observed abnormalities. Furthermore, autonomic dysregulation is a prominent feature of common gastrointestinal disorders, such as irritable bowel syndrome and peptic ulcer disease. Patients with irritable bowel syndrome and other gastrointestinal disorders frequently develop altered pain perception and affective symptoms. CRH acts peripherally to modulate bowel activity both directly through the autonomic system and centrally by processing viscerosensory and visceromotor neural signals. This review presents clinical and preclinical evidence for the role of CRH in the pathophysiology of these disorders and for potential diagnostic and therapeutic applications of CRHR1 antagonists. Recognition of a dysfunctional stress system in these and other diseases will alter the understanding and treatment of

  9. Structural and energetic effects of A2A adenosine receptor mutations on agonist and antagonist binding.

    Directory of Open Access Journals (Sweden)

    Henrik Keränen

    Full Text Available To predict structural and energetic effects of point mutations on ligand binding is of considerable interest in biochemistry and pharmacology. This is not only useful in connection with site-directed mutagenesis experiments, but could also allow interpretation and prediction of individual responses to drug treatment. For G-protein coupled receptors systematic mutagenesis has provided the major part of functional data as structural information until recently has been very limited. For the pharmacologically important A(2A adenosine receptor, extensive site-directed mutagenesis data on agonist and antagonist binding is available and crystal structures of both types of complexes have been determined. Here, we employ a computational strategy, based on molecular dynamics free energy simulations, to rationalize and interpret available alanine-scanning experiments for both agonist and antagonist binding to this receptor. These computer simulations show excellent agreement with the experimental data and, most importantly, reveal the molecular details behind the observed effects which are often not immediately evident from the crystal structures. The work further provides a distinct validation of the computational strategy used to assess effects of point-mutations on ligand binding. It also highlights the importance of considering not only protein-ligand interactions but also those mediated by solvent water molecules, in ligand design projects.

  10. Lower lid entropion secondary to treatment with alpha-1a receptor antagonist: a case report

    Directory of Open Access Journals (Sweden)

    Simcock Peter

    2010-03-01

    Full Text Available Abstract Introduction The use of alpha-1a receptor antagonists (tamsulosin is widely accepted in the treatment of benign prostatic hypertrophy (BPH. It has previously been implicated as a causative agent in intra-operative floppy iris syndrome due to its effects on the smooth muscle. We report a case of lower lid entropion that may be related to a patient commencing treatment of tamsulosin. Case presentation A 74-year-old Caucasian man was started on alpha 1-a receptor antagonist (Tamsulosin treatment for benign prostatic hypertrophy. Eight days later, he presented to the ophthalmology unit with a right lower lid entropion which was successfully treated surgically with a Weiss procedure. Conclusion We report a case of lower lid entropion that may be secondary to the recent use of an alpha-1a blocker (tamsulosin. This can be explained by considering the effect of autonomic blockade on alpha-1 receptors in the Muller's muscle on a patient that may already have an anatomical predisposition to entropion formation due to a further reduction in muscle tone.

  11. Identification of androgen receptor antagonists: In vitro investigation and classification methodology for flavonoid.

    Science.gov (United States)

    Wu, Yang; Doering, Jon A; Ma, Zhiyuan; Tang, Song; Liu, Hongling; Zhang, Xiaowei; Wang, Xiaoxiang; Yu, Hongxia

    2016-09-01

    A tremendous gap exists between the number of potential endocrine disrupting chemicals (EDCs) possibly in the environment and the limitation of traditional regulatory testing. In this study, the anti-androgenic potencies of 21 flavonoids were analyzed in vitro, and another 32 flavonoids from the literature were selected as additional chemicals. Molecular dynamic simulations were employed to obtain four different separation approaches based on the different behaviors of ligands and receptors during the process of interaction. Specifically, ligand-receptor complex which highlighted the discriminating features of ligand escape or retention via "mousetrap" mechanism, hydrogen bonds formed during simulation times, ligand stability and the stability of the helix-12 of the receptor were investigated. Together, a methodology was generated that 87.5% of flavonoids could be discriminated as active versus inactive antagonists, and over 90% inactive antagonists could be filtered out before QSAR study. This methodology could be used as a "proof of concept" to identify inactive anti-androgenic flavonoids, as well could be beneficial for rapid risk assessment and regulation of multiple new chemicals for androgenicity. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Agonist and antagonist binding to rat brain muscarinic receptors: influence of aging

    International Nuclear Information System (INIS)

    Gurwitz, D.; Egozi, Y.; Henis, Y.I.; Kloog, Y.; Sokolovsky, M.

    1987-01-01

    The objective of the present study was to determine the binding properties of muscarinic receptors in six brain regions in mature and old rats of both sexes by employing direct binding of [ 3 H]-antagonist as well as of the labeled natural neurotransmitter, [ 3 H]-acetylcholine [( 3 H]-AcCh). In addition, age-related factors were evaluated in the modulation processes involved in agonist binding. The results indicate that as the rat ages the density of the muscarinic receptors is altered differently in the various brain regions: it is decreased in the cerebral cortex, hippocampus, striatum and olfactory bulb of both male and female rats, but is increased (58%) in the brain stem of senescent males while no significant change is observed for females. The use of the highly sensitive technique measuring direct binding of [ 3 H]-AcCh facilitated the separate detection of age-related changes in the two classes (high- and low-affinity) of muscarinic agonist binding sites. In old female rats the density of high-affinity [ 3 H]-AcCh binding sites was preserved in all tissues studied, indicating that the decreases in muscarinic receptor density observed with [ 3 H]-antagonist represent a loss of low-affinity agonist binding sites. In contrast, [ 3 H]-AcCh binding is decreased in the hypothalamus and increased in the brain stem of old male rats. These data imply sexual dimorphism of the aging process in central cholinergic mechanisms

  13. Receptor residence time trumps drug-likeness and oral bioavailability in determining efficacy of complement C5a antagonists

    Science.gov (United States)

    Seow, Vernon; Lim, Junxian; Cotterell, Adam J.; Yau, Mei-Kwan; Xu, Weijun; Lohman, Rink-Jan; Kok, W. Mei; Stoermer, Martin J.; Sweet, Matthew J.; Reid, Robert C.; Suen, Jacky Y.; Fairlie, David P.

    2016-04-01

    Drug discovery and translation are normally based on optimizing efficacy by increasing receptor affinity, functional potency, drug-likeness (rule-of-five compliance) and oral bioavailability. Here we demonstrate that residence time of a compound on its receptor has an overriding influence on efficacy, exemplified for antagonists of inflammatory protein complement C5a that activates immune cells and promotes disease. Three equipotent antagonists (3D53, W54011, JJ47) of inflammatory responses to C5a (3nM) were compared for drug-likeness, receptor affinity and antagonist potency in human macrophages, and anti-inflammatory efficacy in rats. Only the least drug-like antagonist (3D53) maintained potency in cells against higher C5a concentrations and had a much longer duration of action (t1/2 ~ 20 h) than W54011 or JJ47 (t1/2 ~ 1-3 h) in inhibiting macrophage responses. The unusually long residence time of 3D53 on its receptor was mechanistically probed by molecular dynamics simulations, which revealed long-lasting interactions that trap the antagonist within the receptor. Despite negligible oral bioavailability, 3D53 was much more orally efficacious than W54011 or JJ47 in preventing repeated agonist insults to induce rat paw oedema over 24 h. Thus, residence time on a receptor can trump drug-likeness in determining efficacy, even oral efficacy, of pharmacological agents.

  14. Design and synthesis of labeled analogs of PhTX-56, a potent and selective AMPA receptor antagonist

    DEFF Research Database (Denmark)

    Andersen, Trine F; Vogensen, Stine B; Jensen, Lars S

    2005-01-01

    Polyamines and polyamine toxins are biologically important molecules, having modulatory effects on nucleotides and proteins. The wasp toxin, philanthotoxin-433 (PhTX-433), is a non-selective and uncompetitive antagonist of ionotropic receptors, such as ionotropic glutamate receptors and nicotinic...

  15. The effects of benzodiazepine-receptor antagonists and partial inverse agonists on acute hepatic encephalopathy in the rat

    NARCIS (Netherlands)

    Bosman, D. K.; van den Buijs, C. A.; de Haan, J. G.; Maas, M. A.; Chamuleau, R. A.

    1991-01-01

    Two benzodiazepine-receptor partial inverse agonists (Ro 15-4513, Ro 15-3505) and one benzodiazepine-receptor antagonist (flumazenil) were administered to rats with hepatic encephalopathy due to acute liver ischemia. Significant improvement (P less than 0.002) of both the clinical grade of hepatic

  16. Cardiovascular effects of intrathecally administered bradykinin in the rat: characterization of receptors with antagonists.

    OpenAIRE

    Lopes, P.; Regoli, D.; Couture, R.

    1993-01-01

    1. The effects of intrathecal (i.t.) pretreatment with selective B1 or B2 kinin receptor antagonists were studied on the cardiovascular response to i.t. injection of bradykinin (BK) in conscious freely moving rats. 2. BK (81 pmol) produced an increase in mean arterial pressure (MAP: 9-13 mmHg) and decrease in heart rate (HR: 20-30 beats min-1) that reached a maximum 2 min after injection. 3. The BK-induced cardiovascular responses were dose-dependently and reversibly reduced by four antagonis...

  17. Comparison of the tumor inhibiting effects of three histamine H2-receptor antagonists.

    Science.gov (United States)

    Tutton, P J; Barkla, D H

    1983-01-01

    Three histamine H2-receptor antagonists, Cimetidine, Metiamide and Ranitidine, were tested for their inhibitory effect on two experimental bowel cancer models. In the first model mitotic rates were measured in dimethylhydrazine-induced tumors of rat colon and in the second model volumetric changes in human large bowel cancer xenografts were assessed. In tumors of rat colon all three drugs were able to suppress mitotic activity, but the effects of Metiamide and Ranitidine were more prolonged than that of Cimetidine in each of two lines of human bowel cancer that were used. Metiamide and Ranitidine were also more effective growth inhibitors than was Cimetidine.

  18. Discovery of MK-3697: a selective orexin 2 receptor antagonist (2-SORA) for the treatment of insomnia.

    Science.gov (United States)

    Roecker, Anthony J; Reger, Thomas S; Mattern, M Christa; Mercer, Swati P; Bergman, Jeffrey M; Schreier, John D; Cube, Rowena V; Cox, Christopher D; Li, Dansu; Lemaire, Wei; Bruno, Joseph G; Harrell, C Meacham; Garson, Susan L; Gotter, Anthony L; Fox, Steven V; Stevens, Joanne; Tannenbaum, Pamela L; Prueksaritanont, Thomayant; Cabalu, Tamara D; Cui, Donghui; Stellabott, Joyce; Hartman, George D; Young, Steven D; Winrow, Christopher J; Renger, John J; Coleman, Paul J

    2014-10-15

    Orexin receptor antagonists have demonstrated clinical utility for the treatment of insomnia. The majority of clinical efforts to date have focused on the development of dual orexin receptor antagonists (DORAs), small molecules that antagonize both the orexin 1 and orexin 2 receptors. Our group has recently disclosed medicinal chemistry efforts to identify highly potent, orally bioavailable selective orexin 2 receptor antagonists (2-SORAs) that possess acceptable profiles for clinical development. Herein we report additional SAR studies within the 'triaryl' amide 2-SORA series focused on improvements in compound stability in acidic media and time-dependent inhibition of CYP3A4. These studies resulted in the discovery of 2,5-disubstituted isonicotinamide 2-SORAs such as compound 24 that demonstrated improved stability and TDI profiles as well as excellent sleep efficacy across species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. 5-HT2A receptor antagonists improve motor impairments in the MPTP mouse model of Parkinson's disease.

    Science.gov (United States)

    Ferguson, Marcus C; Nayyar, Tultul; Deutch, Ariel Y; Ansah, Twum A

    2010-01-01

    Clinical observations have suggested that ritanserin, a 5-HT(2A/C) receptor antagonist may reduce motor deficits in persons with Parkinson's Disease (PD). To better understand the potential antiparkinsonian actions of ritanserin, we compared the effects of ritanserin with the selective 5-HT(2A) receptor antagonist M100907 and the selective 5-HT(2C) receptor antagonist SB 206553 on motor impairments in mice treated with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). MPTP-treated mice exhibited decreased performance on the beam-walking apparatus. These motor deficits were reversed by acute treatment with L-3,4-dihydroxyphenylalanine (levodopa). Both the mixed 5-HT(2A/C) antagonist ritanserin and the selective 5-HT(2A) antagonist M100907 improved motor performance on the beam-walking apparatus. In contrast, SB 206553 was ineffective in improving the motor deficits in MPTP-treated mice. These data suggest that 5-HT(2A) receptor antagonists may represent a novel approach to ameliorate motor symptoms of Parkinson's disease. Published by Elsevier Ltd.

  20. Common influences of non-competitive NMDA receptor antagonists on the consolidation and reconsolidation of cocaine-cue memory.

    Science.gov (United States)

    Alaghband, Yasaman; Marshall, John F

    2013-04-01

    Environmental stimuli or contexts previously associated with rewarding drugs contribute importantly to relapse among addicts, and research has focused on neurobiological processes maintaining those memories. Much research shows contributions of cell surface receptors and intracellular signaling pathways in maintaining associations between rewarding drugs (e.g., cocaine) and concurrent cues/contexts; these memories can be degraded at the time of their retrieval through reconsolidation interference. Much less studied is the consolidation of drug-cue memories during their acquisition. The present experiments use the cocaine-conditioned place preference (CPP) paradigm in rats to directly compare, in a consistent setting, the effects of N-methyl-D-aspartate (NMDA) glutamate receptor antagonists MK-801 and memantine on the consolidation and reconsolidation of cocaine-cue memories. For the consolidation studies, animals were systemically administered MK-801 or memantine immediately following training sessions. To investigate the effects of these NMDA receptor antagonists on the retention of previously established cocaine-cue memories, animals were systemically administered MK-801 or memantine immediately after memory retrieval. Animals given either NMDA receptor antagonist immediately following training sessions did not establish a preference for the cocaine-paired compartment. Post-retrieval administration of either NMDA receptor antagonist attenuated the animals' preference for the cocaine-paired compartment. Furthermore, animals given NMDA receptor antagonists post-retrieval showed a blunted response to cocaine-primed reinstatement. Using two distinct NMDA receptor antagonists in a common setting, these findings demonstrate that NMDA receptor-dependent processes contribute both to the consolidation and reconsolidation of cocaine-cue memories, and they point to the potential utility of treatments that interfere with drug-cue memory reconsolidation.

  1. An assessment of the effects of serotonin 6 (5-HT6) receptor antagonists in rodent models of learning.

    Science.gov (United States)

    Lindner, Mark D; Hodges, Donald B; Hogan, John B; Orie, Anitra F; Corsa, Jason A; Barten, Donna M; Polson, Craig; Robertson, Barbara J; Guss, Valerie L; Gillman, Kevin W; Starrett, John E; Gribkoff, Valentin K

    2003-11-01

    Antagonists of serotonin 6 (5-HT6) receptors have been reported to enhance cognition in animal models of learning, although this finding has not been universal. We have assessed the therapeutic potential of the specific 5-HT6 receptor antagonists 4-amino-N-(2,6-bis-methylamino-pyrimidin-4-yl)-benzenesulfonamide (Ro 04-6790) and 5-chloro-N-(4-methoxy-3-piperazin-1-yl-phenyl)-3-methyl-2-benzothiophenesulfonamide (SB-271046) in rodent models of cognitive function. Although mice express the 5-HT6 receptor and the function of this receptor has been investigated in mice, all reports of activity with 5-HT6 receptor antagonists have used rat models. In the present study, receptor binding revealed that the pharmacological properties of the mouse receptor are different from the rat and human receptor: Ro 04-6790 does not bind to the mouse 5-HT6 receptor, so all in vivo testing included in the present report was conducted in rats. We replicated previous reports that 5-HT6 receptor antagonists produce a stretching syndrome previously shown to be mediated through cholinergic mechanisms, but Ro 04-6790 and SB-271046 failed to attenuate scopolamine-induced deficits in a test of contextual fear conditioning. We also failed to replicate the significant effects reported previously in both an autoshaping task and in a version of the Morris water maze. The results of our experiments are not consistent with previous reports that suggested that 5-HT6 antagonists might have therapeutic potential for cognitive disorders.

  2. Analysis of hydrophobic interactions of antagonists with the beta2-adrenergic receptor.

    Science.gov (United States)

    Novoseletsky, V N; Pyrkov, T V; Efremov, R G

    2010-01-01

    The adrenergic receptors mediate a wide variety of physiological responses, including vasodilatation and vasoconstriction, heart rate modulation, and others. Beta-adrenergic antagonists ('beta-blockers') thus constitute a widely used class of drugs in cardiovascular medicine as well as in management of anxiety, migraine, and glaucoma. The importance of the hydrophobic effect has been evidenced for a wide range of beta-blocker properties. To better understand the role of the hydrophobic effect in recognition of beta-blockers by their receptor, we carried out a molecular docking study combined with an original approach to estimate receptor-ligand hydrophobic interactions. The proposed method is based on automatic detection of molecular fragments in ligands and the analysis of their interactions with receptors separately. A series of beta-blockers, based on phenylethanolamines and phenoxypropanolamines, were docked to the beta2-adrenoceptor binding site in the crystal structure. Hydrophobic complementarity between the ligand and the receptor was calculated using the PLATINUM web-server (http://model.nmr.ru/platinum). Based on the analysis of the hydrophobic match for molecular fragments of beta-blockers, we have developed a new scoring function which efficiently predicts dissociation constant (pKd) with strong correlations (r(2) approximately 0.8) with experimental data.

  3. Effects of cannabinoid and glutamate receptor antagonists and their interactions on learning and memory in male rats.

    Science.gov (United States)

    Barzegar, Somayeh; Komaki, Alireza; Shahidi, Siamak; Sarihi, Abdolrahman; Mirazi, Naser; Salehi, Iraj

    2015-04-01

    Despite previous findings on the effects of cannabinoid and glutamatergic systems on learning and memory, the effects of the combined stimulation or the simultaneous inactivation of these two systems on learning and memory have not been studied. In addition, it is not clear whether the effects of the cannabinoid system on learning and memory occur through the modulation of glutamatergic synaptic transmission. Hence, in this study, we examined the effects of the simultaneous inactivation of the cannabinoid and glutamatergic systems on learning and memory using a passive avoidance (PA) test in rats. On the test day, AM251, which is a CB1 cannabinoid receptor antagonist; MK-801, which is a glutamate receptor antagonist; or both substances were injected intraperitoneally into male Wistar rats 30min before placing the animal in a shuttle box. A learning test (acquisition) was then performed, and a retrieval test was performed the following day. Learning and memory in the PA test were significantly different among the groups. The CB1 receptor antagonist improved the scores on the PA acquisition and retention tests. However, the glutamatergic receptor antagonist decreased the acquisition and retrieval scores on the PA task. The CB1 receptor antagonist partly decreased the glutamatergic receptor antagonist effects on PA learning and memory. These results indicated that the acute administration of a CB1 antagonist improved cognitive performance on a PA task in normal rats and that a glutamate-related mechanism may underlie the antagonism of cannabinoid by AM251 in learning and memory. Copyright © 2015 Elsevier Inc. All rights reserved.

  4. Cost-effectiveness of histamine receptor-2 antagonist versus proton pump inhibitor for stress ulcer prophylaxis in critically ill patients*.

    Science.gov (United States)

    MacLaren, Robert; Campbell, Jon

    2014-04-01

    To examine the cost-effectiveness of using histamine receptor-2 antagonist or proton pump inhibitor for stress ulcer prophylaxis. Decision analysis model examining costs and effectiveness of using histamine receptor-2 antagonist or proton pump inhibitor for stress ulcer prophylaxis. Costs were expressed in 2012 U.S. dollars from the perspective of the institution and included drug regimens and the following outcomes: clinically significant stress-related mucosal bleed, ventilator-associated pneumonia, and Clostridium difficile infection. Effectiveness was the mortality risk associated with these outcomes and represented by survival. Costs, occurrence rates, and mortality probabilities were extracted from published data. A simulation model. A mixed adult ICU population. Histamine receptor-2 antagonist or proton pump inhibitor for 9 days of stress ulcer prophylaxis therapy. Output variables were expected costs, expected survival rates, incremental cost, and incremental survival rate. Univariate sensitivity analyses were conducted to determine the drivers of incremental cost and incremental survival. Probabilistic sensitivity analysis was conducted using second-order Monte Carlo simulation. For the base case analysis, the expected cost of providing stress ulcer prophylaxis was $6,707 with histamine receptor-2 antagonist and $7,802 with proton pump inhibitor, resulting in a cost saving of $1,095 with histamine receptor-2 antagonist. The associated mortality probabilities were 3.819% and 3.825%, respectively, resulting in an absolute survival benefit of 0.006% with histamine receptor-2 antagonist. The primary drivers of incremental cost and survival were the assumptions surrounding ventilator-associated pneumonia and bleed. The probabilities that histamine receptor-2 antagonist was less costly and provided favorable survival were 89.4% and 55.7%, respectively. A secondary analysis assuming equal rates of C. difficile infection showed a cost saving of $908 with histamine

  5. Novel 5-HT6 receptor antagonists/D2 receptor partial agonists targeting behavioral and psychological symptoms of dementia.

    Science.gov (United States)

    Kołaczkowski, Marcin; Marcinkowska, Monika; Bucki, Adam; Śniecikowska, Joanna; Pawłowski, Maciej; Kazek, Grzegorz; Siwek, Agata; Jastrzębska-Więsek, Magdalena; Partyka, Anna; Wasik, Anna; Wesołowska, Anna; Mierzejewski, Paweł; Bienkowski, Przemyslaw

    2015-03-06

    We describe a novel class of designed multiple ligands (DMLs) combining serotonin 5-HT6 receptor (5-HT6R) antagonism with dopamine D2 receptor (D2R) partial agonism. Prototype hybrid molecules were designed using docking to receptor homology models. Diverse pharmacophore moieties yielded 3 series of hybrids with varying in vitro properties at 5-HT6R and D2R, and at M1 receptor and hERG channel antitargets. 4-(piperazin-1-yl)-1H-indole derivatives showed highest antagonist potency at 5-HT6R, with 7-butoxy-3,4-dihydroquinolin-2(1H)-one and 2-propoxybenzamide derivatives having promising D2R partial agonism. 2-(3-(4-(1-(phenylsulfonyl)-1H-indol-4-yl)piperazin-1-yl)propoxy)benzamide (47) exhibited nanomolar affinity at both 5-HT6R and D2R and was evaluated in rat models. It displayed potent antidepressant-like and anxiolytic-like activity in the Porsolt and Vogel tests, respectively, more pronounced than that of a reference selective 5-HT6R antagonist or D2R partial agonist. In addition, 47 also showed antidepressant-like activity (Porsolt's test) and anxiolytic-like activity (open field test) in aged (>18-month old) rats. In operant conditioning tests, 47 enhanced responding for sweet reward in the saccharin self-administration test, consistent with anti-anhedonic properties. Further, 47 facilitated extinction of non-reinforced responding for sweet reward, suggesting potential procognitive activity. Taken together, these studies suggest that DMLs combining 5-HT6R antagonism and D2R partial agonism may successfully target affective disorders in patients from different age groups without a risk of cognitive deficits. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  6. Oxytocin receptor antagonist atosiban impairs consolidation, but not reconsolidation of contextual fear memory in rats.

    Science.gov (United States)

    Abdullahi, Payman Rasise; Eskandarian, Sharaf; Ghanbari, Ali; Rashidy-Pour, Ali

    2018-05-23

    There is increasing evidence that oxytocin is involved in learning and memory process. This study investigated the effects of blockade of oxytocin receptors using the selective oxytocin receptor antagonist atosiban (ATO) on contextual fear memory consolidation and reconsolidation in male rats. Post-training injections of different doses of ATO (1, 10, 100 or 1000 µg/kg) impaired the 48 h retention performance in a dose-dependent manner. The same doses of ATO following memory reactivation did not impair subsequent expression of contextual fear memories which formed under low or high shock intensities and tested 24 h or one week following memory reactivation. Also, no effect was found when ATO was administrated in the absence of memory reactivation. Our finding is the first report that indicates endogenous oxytocin released during training play an important role in the consolidation, but not reconsolidation of contextual fear memory in rats. Copyright © 2018. Published by Elsevier B.V.

  7. Characterization of muscarinic receptor subtypes in primary cultures of cerebellar granule cells using specific muscarinic receptor antagonists

    International Nuclear Information System (INIS)

    McLeskey, S.W.

    1989-01-01

    In cerebellar granule cell cultures, two muscarinic receptor mediated responses were observed: inhibition of adenylate cyclase (M-AC) and stimulation of phosphoinositide hydrolysis (M-PI). These responses were antagonized by three purported specific muscarinic antagonists: pirenzipine and (-)QNX (specific for M-PI) and methoctramine (specific for M-AC). However, the specificity for the three antagonists in blocking these responses is not comparable to the specificity observed in binding studies on these cells or to that quoted in the literature. Two peaks of molecular sizes were found in these cells corresponding to the two molecular sizes of muscarinic receptive proteins reported in the literature. Muscarinic receptive proteins were alkylated with 3 H-propylbenzilylcholine mustard followed by sodium dodecylsulfate polyacrylamide gel electrophoresis. Pirenzipine and (-)QNX were able to block alkylation of the high molecular size peak, which corresponds to the receptive protein m 3 reported in the literature. Methoctramine was able to block alkylation of a portion of the lower molecular size peak, possibly corresponding to the m 2 and/or m 4 receptive proteins reported in the literature. Studies attempting to show the presence of receptor reserve for either of the two biochemical responses present in these cells by alkylation of the receptive protein with nonradiolabeled propylbenzilylcholine mustard (PBCM) were confounded by specificity of this agent for the lower molecular weight peak of muscarinic receptive protein. Thus the muscarinic receptive proteins coupled to M-AC were alkylated preferentially over the ones coupled to M-PI

  8. Selective Glucocorticoid Receptor (GR-II Antagonist Reduces Body Weight Gain in Mice

    Directory of Open Access Journals (Sweden)

    Tomoko Asagami

    2011-01-01

    Full Text Available Previous research has shown that mifepristone can prevent and reverse weight gain in animals and human subjects taking antipsychotic medications. This proof-of-concept study tested whether a more potent and selective glucocorticoid receptor antagonist could block dietary-induced weight gain and increase insulin sensitivity in mice. Ten-week-old, male, C57BL/6J mice were fed a diet containing 60% fat calories and water supplemented with 11% sucrose for 4 weeks. Groups (=8 received one of the following: CORT 108297 (80 mg/kg QD, CORT 108297 (40 mg/kg BID, mifepristone (30 mg/kg BID, rosiglitazone (10 mg/kg QD, or vehicle. Compared to mice receiving a high-fat, high-sugar diet plus vehicle, mice receiving a high-fat, high-sugar diet plus either mifepristone or CORT 108297 gained significantly less weight. At the end of the four week treatment period, mice receiving CORT 108297 40 mg/kg BID or CORT 108297 80 mg/kg QD also had significantly lower steady plasma glucose than mice receiving vehicle. However, steady state plasma glucose after treatment was not highly correlated with reduced weight gain, suggesting that the effect of the glucocorticoid receptor antagonist on insulin sensitivity may be independent of its mitigating effect on weight gain.

  9. GLP-1 receptor antagonist as a potential probe for pancreatic β-cell imaging

    International Nuclear Information System (INIS)

    Mukai, Eri; Toyoda, Kentaro; Kimura, Hiroyuki; Kawashima, Hidekazu; Fujimoto, Hiroyuki; Ueda, Masashi; Temma, Takashi; Hirao, Konomu; Nagakawa, Kenji; Saji, Hideo; Inagaki, Nobuya

    2009-01-01

    We examined exendin(9-39), an antagonist of glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), as a potential probe for imaging of pancreatic β-cells. To evaluate in vitro receptor specificity, binding assay was performed using dispersed mouse islet cells. Binding assay showed competitive inhibition of [ 125 I]BH-exendin(9-39) binding by non-radioactive exendin(9-39). To assess in vivo selectivity, the biodistribution was evaluated by intravenous administration of [ 125 I]BH-exendin(9-39) to mice. Radioactivity of harvested pancreas reached highest levels at 60 and 120 min among organs examined except lung. Pre-administration of excess non-radioactive exendin(9-39) remarkably and specifically blocked the radioactivity of pancreas. After [ 125 I]BH-exendin(9-39) injection into transgenic mice with pancreatic β-cells expressing GFP, fluorescent and radioactive signals of sections of pancreas were evaluated with an image analyzer. Imaging analysis showed that the fluorescent GFP signals and the radioactive signals were correspondingly located. Thus, the GLP-1R antagonist exendin(9-39) may serve as a useful probe for pancreatic β-cell imaging.

  10. Pegvisomant: a growth hormone receptor antagonist used in the treatment of acromegaly.

    Science.gov (United States)

    Tritos, Nicholas A; Biller, Beverly M K

    2017-02-01

    To review published data on pegvisomant and its therapeutic role in acromegaly. Electronic searches of the published literature were conducted using the keywords: acromegaly, growth hormone (GH) receptor (antagonist), pegvisomant, therapy. Relevant articles (n = 141) were retrieved and considered for inclusion in this manuscript. Pegvisomant is a genetically engineered, recombinant growth hormone receptor antagonist, which is effective in normalizing serum insulin-like growth factor 1 (IGF-1) levels in the majority of patients with acromegaly and ameliorating symptoms and signs associated with GH excess. Pegvisomant does not have direct antiproliferative effects on the underlying somatotroph pituitary adenoma, which is the etiology of GH excess in the vast majority of patients with acromegaly. Therefore, patients receiving pegvisomant monotherapy require regular pituitary imaging in order to monitor for possible increase in tumor size. Adverse events in patients on pegvisomant therapy include skin rashes, lipohypertrophy at injection sites, and idiosyncratic liver toxicity (generally asymptomatic transaminitis that is reversible upon drug discontinuation), thus necessitating regular patient monitoring. Pegvisomant is an effective therapeutic agent in patients with acromegaly who are not in remission after undergoing pituitary surgery. It mitigates excess GH action, as demonstrated by IGF-1 normalization, but has no direct effects on pituitary tumors causing acromegaly. Regular surveillance for possible tumor growth and adverse effects (hepatotoxicity, skin manifestations) is warranted.

  11. Effect of NMDA Receptor Antagonist on Local Cerebral Glucose Metabolic Rate in Focal Cerebral Ischemia

    International Nuclear Information System (INIS)

    Kim, Sang Eun; Hong, Seung Bong; Yoon, Byung Woo

    1995-01-01

    There has recently been increasing interest in the use of NMDA receptor antagonists as potential neuroprotective agents for the treatment of ischemic stroke. To evaluate the neuroprotective effect of the selective non-competitive NMDA receptor antagonist MK-801 in focal cerebral ischemia, local cerebral glucose utilization (1CGU) was examined in 15 neuroanatomically discrete regions of the conscious rat brain using the 2-deoxy-D[14C]glucose quantitative autoradiographic technique 24 hr after left middle cerebral artery occlusion (MCAO). Animals received MK-801 (5 mg/kg i.v.) or saline vehicle before (20-30 min) or after (30 min) MCAO. Both pretreatment and posttreatment of MK-801 increased occluded/non-occluded 1CGU ratio in 7 and 5 of the 15 regions measured, respectively(most notably in cortical structures). Following MK-801 pretreatment, there was evidence of widespread increases in 1CCPU not only in the non-occluded hemisphere (12 of the 15 areas studied) but also in the occluded hemisphere (13 of the 15 areas studied), while MK-801 posttreatment did not significantly increase 1CGU both in the normal and occluded hemispheres. These data indicate that MK-801 has a neuroprotective effect in focal cerebral ischemia and demonstrate that MK-801 provides widespread alterations of glucose utilization in conscious animals.

  12. Clinical Validation of a Pixon-Based Reconstruction Method Allowing a Twofold Reduction in Planar Images Time of 111In-Pentetreotide Somatostatin Receptor Scintigraphy

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    Philippe Thuillier

    2017-08-01

    Full Text Available ObjectiveThe objective of this study was to evaluate the diagnostic efficacy of Pixon-based reconstruction method on planar somatostatin receptor scintigraphy (SRS.MethodsAll patients with neuroendocrine tumors (NETs disease who were referred for SRS to our department during 1-year period from January to December 2015 were consecutively included. Three nuclear physicians independently reviewed all the data sets of images which included conventional images (CI; 15 min/view and processed images (PI obtained by reconstructing the first 450 s extracted data using Oncoflash® software package. Image analysis using a 3-point rating scale for abnormal uptake of 111 Indium-DTPA-Phe-octreotide in any lesion or organ was interpreted as positive, uncertain, or negative for the evidence of NET disease. A maximum grade uptake of the radiotracer in the lesion was assessed by the Krenning scale method. The results of image interpretation by the two methods were considered significantly discordant when the difference in organ involvement assessment was negative vs. positive or in lesion uptake was ≥2 grades. Agreement between the results of two methods and by different scan observers was evaluated using Cohen κ coefficients.ResultsThere was no significant (p = 0.403 correlation between data acquisition protocol and quality image. The rates of significant discrepancies for exam interpretation and organs involvement assessment were 2.8 and 2.6%, respectively. Mean κ values revealed a good agreement for concordance between CI and PI interpretation without difference of agreement for inter/intra-observer analysis.ConclusionOur results suggest the feasibility to use a Pixon-based reconstruction method for SRS planar images allowing a twofold reduction of acquisition time and without significant alteration of image quality or on image interpretation.

  13. Concordance between results of somatostatin receptor scintigraphy with 111In-DOTA-DPhe1-Tyr3-octreotide and chromogranin A assay in patients with neuroendocrine tumours

    International Nuclear Information System (INIS)

    Rodrigues, Margarida; Gabriel, Michael; Heute, Dirk; Putzer, Daniel; Virgolini, Irene; Griesmacher, Andrea

    2008-01-01

    Somatostatin receptor scintigraphy (SRS) and chromogranin A (CgA) assay have successfully been implemented in the clinical work-up and management of neuroendocrine tumour (NET) patients. However, there is still a lack of studies comparing results in these patients. Our aim was to compare directly in NET patients SRS and CgA assay results with special regard to tumour features such as grade of malignancy, primary origin, disease extent and function. One hundred twenty consecutive patients with histological confirmed NETs were investigated with 111 In-DOTA-DPhe 1 -Tyr 3 -octreotide ( 111 In-DOTA-TOC) SRS and CgA immunoradiometric assay. Tumours were classified by cell characteristics [well-differentiated NETs, well-differentiated neuroendocrine carcinomas, poorly differentiated neuroendocrine carcinomas (PDNECs)], primary origin (foregut, midgut, hindgut, undetermined), disease extent (limited disease, metastases, primary tumour and metastases) and functionality (secretory, nonsecretory). SRS was positive in 107 (89%) patients; CgA levels were increased in 95 (79%) patients. Overall, concordance between SRS and CgA results was found in 84 patients. Positive SRS but normal CgA level were found in 24 patients, with higher prevalence (p 111 In-DOTA-TOC SRS proved to be more sensitive than CgA in NETs patients. Tumour differentiation, disease extent and presence of liver metastases impact both SRS and CgA results, whereas nonsecretory activity is a negative predictor of only CgA increase. PDNECs and hindgut origin of tumours predispose to discrepancies with negative SRS but increased CgA levels. (orig.)

  14. Concordance between results of somatostatin receptor scintigraphy with 111In-DOTA-DPhe 1-Tyr 3-octreotide and chromogranin A assay in patients with neuroendocrine tumours.

    Science.gov (United States)

    Rodrigues, Margarida; Gabriel, Michael; Heute, Dirk; Putzer, Daniel; Griesmacher, Andrea; Virgolini, Irene

    2008-10-01

    Somatostatin receptor scintigraphy (SRS) and chromogranin A (CgA) assay have successfully been implemented in the clinical work-up and management of neuroendocrine tumour (NET) patients. However, there is still a lack of studies comparing results in these patients. Our aim was to compare directly in NET patients SRS and CgA assay results with special regard to tumour features such as grade of malignancy, primary origin, disease extent and function. One hundred twenty consecutive patients with histological confirmed NETs were investigated with (111)In-DOTA-DPhe(1)-Tyr(3)-octreotide ((111)In-DOTA-TOC) SRS and CgA immunoradiometric assay. Tumours were classified by cell characteristics [well-differentiated NETs, well-differentiated neuroendocrine carcinomas, poorly differentiated neuroendocrine carcinomas (PDNECs)], primary origin (foregut, midgut, hindgut, undetermined), disease extent (limited disease, metastases, primary tumour and metastases) and functionality (secretory, nonsecretory). SRS was positive in 107 (89%) patients; CgA levels were increased in 95 (79%) patients. Overall, concordance between SRS and CgA results was found in 84 patients. Positive SRS but normal CgA level were found in 24 patients, with higher prevalence (p<0.05) in patients with nonsecretory tumours. Conversely, negative SRS but CgA level increased were seen in 12 patients, with higher proportion (p<0.05) in patients with PDNECs and tumours of hindgut origin. Overall, (111)In-DOTA-TOC SRS proved to be more sensitive than CgA in NETs patients. Tumour differentiation, disease extent and presence of liver metastases impact both SRS and CgA results, whereas nonsecretory activity is a negative predictor of only CgA increase. PDNECs and hindgut origin of tumours predispose to discrepancies with negative SRS but increased CgA levels.

  15. Gastroenteropancreatic Neuroendocrine Tumors: Standardizing Therapy Monitoring with 68Ga-DOTATOC PET/CT Using the Example of Somatostatin Receptor Radionuclide Therapy

    Directory of Open Access Journals (Sweden)

    Wolfgang Luboldt

    2010-11-01

    Full Text Available The purpose of this study was to standardize therapy monitoring of hepatic metastases from gastroenteropancreatic neuroendocrine tumors (GEP-NETs during the course of somatostatin receptor radionuclide therapy (SRRT. In 21 consecutive patients with nonresectable hepatic metastases of GEP-NETs, chromogranin A (CgA and 68Ga-DOTATOC PET/CT were compared before and after the last SRRT. On 68Ga-DOTATOC PET/CT, the maximum standard uptake values (SUVmax of normal liver and hepatic metastases were calculated. In addition, the volumes of hepatic metastases (volume of interest [VOI] were measured using four cut-offs to separate normal liver tissue from metastases (SUVmax of the normal liver plus 10% [VOIliver+10%], 20% [VOIliver+20%], 30% [VOIliver+30%] and SUV = 10 [VOI10SUV]. The SUVmaxof the normal liver was below 10 (7.2 ± 1.3 in all patients and without significant changes. Overall therapy changes (Δ per patient (mean [95% CI] were statistically significant with p < .01 for ΔCgA = −43 (−69 to −17, ΔSUVmax = −22 (−29 to −14, and ΔVOI10SUV = −53 (−68 to −38% and significant with p < .05 for ΔVOIliver+10% = −29 (−55 to −3%, ΔVOIliver+20% = −32 (−62 to −2 and ΔVOIliver+30% = −37 (−66 to −8. Correlations were found only between ΔCgA and ΔVOI10SUV (r = .595; p < .01, ΔSUVmax and ΔVOI10SUV (0.629, p < .01, and SUVmax and ΔSUVmax (r = .446; p < .05. 68Ga-DOTATOC PET/CT allows volumetric therapy monitoring via an SUV-based cut-off separating hepatic metastases from normal liver tissue (10 SUV recommended.

  16. Somatostatin-receptor-targeted α-emitting 213Bi is therapeutically more effective than β--emitting 177Lu in human pancreatic adenocarcinoma cells

    International Nuclear Information System (INIS)

    Nayak, Tapan K.; Norenberg, Jeffrey P.; Anderson, Tamara L.; Prossnitz, Eric R.; Stabin, Michael G.; Atcher, Robert W.

    2007-01-01

    Introduction: Advance clinical cancer therapy studies of patients treated with somatostatin receptor (sstr)-targeted [DOTA 0 -Tyr 3 ]octreotide (DOTATOC) labeled with low-linear-energy-transfer (LET) β - -emitters have shown overall response rates in the range of 15-33%. In order to improve outcomes, we sought to compare the therapeutic effectiveness of sstr-targeted high-LET α-emitting 213 Bi to that of low-LET β - -emitting 177 Lu by determining relative biological effectiveness (RBE) using the external γ-beam of 137 Cs as reference radiation. Methods: Sstr-expressing human pancreatic adenocarcinoma Capan-2 cells and A549 control cells were used for this study. The effects of different radiation doses of 213 Bi and 177 Lu labeled to 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid and sstr-targeted DOTATOC were investigated with a clonogenic cell survival assay. Apoptosis was measured using the Cell Death Detection ELISA PLUS 10x kit. Results: Using equimolar DOTATOC treatment with concurrent irradiation with a 137 Cs source as reference radiation, the calculated RBE of [ 213 Bi]DOTATOC was 3.4, as compared to 1.0 for [ 177 Lu]DOTATOC. As measured in terms of absorbance units, [ 213 Bi]DOTATOC caused a 2.3-fold-greater release of apoptosis-specific mononucleosomes and oligonucleosomes than [ 177 Lu]DOTATOC at the final treatment time of 96 h (P 213 Bi]DOTATOC is therapeutically more effective in decreasing survival than is [ 177 Lu]DOTATOC in human pancreatic adenocarcinoma cells due to its comparatively higher RBE

  17. SR 144528, the first potent and selective antagonist of the CB2 cannabinoid receptor.

    Science.gov (United States)

    Rinaldi-Carmona, M; Barth, F; Millan, J; Derocq, J M; Casellas, P; Congy, C; Oustric, D; Sarran, M; Bouaboula, M; Calandra, B; Portier, M; Shire, D; Brelière, J C; Le Fur, G L

    1998-02-01

    Based on both binding and functional data, this study introduces SR 144528 as the first, highly potent, selective and orally active antagonist for the CB2 receptor. This compound which displays subnanomolar affinity (Ki = 0.6 nM) for both the rat spleen and cloned human CB2 receptors has a 700-fold lower affinity (Ki = 400 nM) for both the rat brain and cloned human CB1 receptors. Furthermore it shows no affinity for any of the more than 70 receptors, ion channels or enzymes investigated (IC50 > 10 microM). In vitro, SR 144528 antagonizes the inhibitory effects of the cannabinoid receptor agonist CP 55,940 on forskolin-stimulated adenylyl cyclase activity in cell lines permanently expressing the h CB2 receptor (EC50 = 10 nM) but not in cells expressing the h CB1 (no effect at 10 microM). Furthermore, SR 144528 is able to selectively block the mitogen-activated protein kinase activity induced by CP 55,940 in cell lines expressing h CB2 (IC50 = 39 nM) whereas in cells expressing h CB1 an IC50 value of more than 1 microM is found. In addition, SR 144528 is shown to antagonize the stimulating effects of CP 55,940 on human tonsillar B-cell activation evoked by cross-linking of surface Igs (IC50 = 20 nM). In vivo, after oral administration SR 144528 totally displaced the ex vivo [3H]-CP 55,940 binding to mouse spleen membranes (ED50 = 0.35 mg/kg) with a long duration of action. In contrast, after the oral route it does not interact with the cannabinoid receptor expressed in the mouse brain (CB1). It is expected that SR 144528 will provide a powerful tool to investigate the in vivo functions of the cannabinoid system in the immune response.

  18. Antidepressant activity of the adenosine A2A receptor antagonist, istradefylline (KW-6002) on learned helplessness in rats.

    Science.gov (United States)

    Yamada, Koji; Kobayashi, Minoru; Shiozaki, Shizuo; Ohta, Teruko; Mori, Akihisa; Jenner, Peter; Kanda, Tomoyuki

    2014-07-01

    Istradefylline, an adenosine A2A receptor antagonist, improves motor function in animal models of Parkinson's disease (PD) and in patients with PD. In addition, some A2A antagonists exert antidepressant-like activity in rodent models of depression, such as the forced swim and the tail suspension tests. We have investigated the effect of istradefylline on depression-like behaviors using the rat learned helplessness (LH) model. Acute, as well as chronic, oral administration of istradefylline significantly improved the inescapable shock (IES)-induced escape deficit with a degree of efficacy comparable to chronic treatment with the tricyclic antidepressant desipramine and the selective serotonin (5-HT) reuptake inhibitor, fluoxetine. Both the A1/A2A receptor nonspecific antagonist theophylline and the moderately selective antagonist CGS15943, but not the A1 selective antagonist DPCPX, ameliorated the IES-induced escape deficit. The enhancement of escape response by istradefylline was reversed by a local injection of the A2A specific agonist CGS21680 either into the nucleus accumbens, the caudate-putamen, or the paraventricular nucleus of the hypothalamus, but not by the A1 specific agonist R-PIA into the nucleus accumbens. Moreover, neither the 5-HT2A/2C receptor antagonist methysergide or the adrenergic α 2 antagonist yohimbine, nor the β-adrenergic antagonist propranolol, affected the improvement of escape response induced by istradefylline. Istradefylline exerts antidepressant-like effects via modulation of A2A receptor activity which is independent of monoaminergic transmission in the brain. Istradefylline may represent a novel treatment option for depression in PD as well as for the motor symptoms.

  19. The role of opioid antagonist efficacy and constitutive opioid receptor activity in the opioid withdrawal syndrome in mice

    OpenAIRE

    Navani, Dipesh M.; Sirohi, Sunil; Madia, Priyanka A.; Yoburn, Byron C.

    2011-01-01

    On the basis of efficacy, opioid antagonists are classified as inverse opioid agonists (e.g. naltrexone) or neutral opioid antagonists (e.g. 6β-naltrexol). This study examined the interaction between naltrexone and 6β-naltrexol in the precipitated opioid withdrawal syndrome in morphine dependent mice. Furthermore, the possible contribution of constitutive opioid receptor activity to precipitated withdrawal was evaluated using increasing levels of morphine dependence. In the first experiment, ...

  20. Neurotensin is an antagonist of the human neurotensin NT2 receptor expressed in Chinese hamster ovary cells.

    Science.gov (United States)

    Vita, N; Oury-Donat, F; Chalon, P; Guillemot, M; Kaghad, M; Bachy, A; Thurneyssen, O; Garcia, S; Poinot-Chazel, C; Casellas, P; Keane, P; Le Fur, G; Maffrand, J P; Soubrie, P; Caput, D; Ferrara, P

    1998-11-06

    The human levocabastine-sensitive neurotensin NT2 receptor was cloned from a cortex cDNA library and stably expressed in Chinese hamster ovary (CHO) cells in order to study its binding and signalling characteristics. The receptor binds neurotensin as well as several other ligands already described for neurotensin NT1 receptor. It also binds levocabastine, a histamine H1 receptor antagonist that is not recognised by neurotensin NT1 receptor. Neurotensin binding to recombinant neurotensin NT2 receptor expressed in CHO cells does not elicit a biological response as determined by second messenger measurements. Levocabastine, and the peptides neuromedin N and xenin were also ineffective on neurotensin NT2 receptor activation. Experiments with the neurotensin NT1 receptor antagonists SR48692 and SR142948A, resulted in the unanticipated discovery that both molecules are potent agonists on neurotensin NT2 receptor. Both compounds, following binding to neurotensin NT2 receptor, enhance inositol phosphates (IP) formation with a subsequent [Ca2+]i mobilisation; induce arachidonic acid release; and stimulate mitogen-activated protein kinase (MAPK) activity. Interestingly, these activities are antagonised by neurotensin and levocabastine in a concentration-dependent manner. These activities suggest that the human neurotensin NT2 receptor may be of physiological importance and that a natural agonist for the receptor may exist.

  1. Pharmacological profile of CS-3150, a novel, highly potent and selective non-steroidal mineralocorticoid receptor antagonist.

    Science.gov (United States)

    Arai, Kiyoshi; Homma, Tsuyoshi; Morikawa, Yuka; Ubukata, Naoko; Tsuruoka, Hiyoyuki; Aoki, Kazumasa; Ishikawa, Hirokazu; Mizuno, Makoto; Sada, Toshio

    2015-08-15

    The present study was designed to characterize the pharmacological profile of CS-3150, a novel non-steroidal mineralocorticoid receptor antagonist. In the radioligand-binding assay, CS-3150 inhibited (3)H-aldosterone binding to mineralocorticoid receptor with an IC50 value of 9.4nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 36 and 713nM, respectively. CS-3150 also showed at least 1000-fold higher selectivity for mineralocorticoid receptor over other steroid hormone receptors, glucocorticoid receptor, androgen receptor and progesterone receptor. In the reporter gene assay, CS-3150 inhibited aldosterone-induced transcriptional activation of human mineralocorticoid receptor with an IC50 value of 3.7nM, and its potency was superior to that of spironolactone and eplerenone, whose IC50s were 66 and 970nM, respectively. CS-3150 had no agonistic effect on mineralocorticoid receptor and did not show any antagonistic or agonistic effect on glucocorticoid receptor, androgen receptor and progesterone receptor even at the high concentration of 5μM. In adrenalectomized rats, single oral administration of CS-3150 suppressed aldosterone-induced decrease in urinary Na(+)/K(+) ratio, an index of in vivo mineralocorticoid receptor activation, and this suppressive effect was more potent and longer-lasting than that of spironolactone and eplerenone. Chronic treatment with CS-3150 inhibited blood pressure elevation induced by deoxycorticosterone acetate (DOCA)/salt-loading to rats, and this antihypertensive effect was more potent than that of spironolactone and eplerenone. These findings indicate that CS-3150 is a selective and highly potent mineralocorticoid receptor antagonist with long-lasting oral activity. This agent could be useful for the treatment of hypertension, cardiovascular and renal disorders. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Medicinal Chemistry, Pharmacology, and Clinical Implications of TRPV1 Receptor Antagonists.

    Science.gov (United States)

    Aghazadeh Tabrizi, Mojgan; Baraldi, Pier Giovanni; Baraldi, Stefania; Gessi, Stefania; Merighi, Stefania; Borea, Pier Andrea

    2017-07-01

    Transient receptor potential vanilloid 1 (TRPV1) is an ion channel expressed on sensory neurons triggering an influx of cations. TRPV1 receptors function as homotetramers responsive to heat, proinflammatory substances, lipoxygenase products, resiniferatoxin, endocannabinoids, protons, and peptide toxins. Its phosphorylation increases sensitivity to both chemical and thermal stimuli, while desensitization involves a calcium-dependent mechanism resulting in receptor dephosphorylation. TRPV1 functions as a sensor of noxious stimuli and may represent a target to avoid pain and injury. TRPV1 activation has been associated to chronic inflammatory pain and peripheral neuropathy. Its expression is also detected in nonneuronal areas such as bladder, lungs, and cochlea where TRPV1 activation is responsible for pathology development of cystitis, asthma, and hearing loss. This review offers a comprehensive overview about TRPV1 receptor in the pathophysiology of chronic pain, epilepsy, cough, bladder disorders, diabetes, obesity, and hearing loss, highlighting how drug development targeting this channel could have a clinical therapeutic potential. Furthermore, it summarizes the advances of medicinal chemistry research leading to the identification of highly selective TRPV1 antagonists and their analysis of structure-activity relationships (SARs) focusing on new strategies to target this channel. © 2016 Wiley Periodicals, Inc.

  3. Residues remote from the binding pocket control the antagonist selectivity towards the corticotropin-releasing factor receptor-1

    Science.gov (United States)

    Sun, Xianqiang; Cheng, Jianxin; Wang, Xu; Tang, Yun; Ågren, Hans; Tu, Yaoquan

    2015-01-01

    The corticotropin releasing factors receptor-1 and receptor-2 (CRF1R and CRF2R) are therapeutic targets for treating neurological diseases. Antagonists targeting CRF1R have been developed for the potential treatment of anxiety disorders and alcohol addiction. It has been found that antagonists targeting CRF1R always show high selectivity, although CRF1R and CRF2R share a very high rate of sequence identity. This has inspired us to study the origin of the selectivity of the antagonists. We have therefore built a homology model for CRF2R and carried out unbiased molecular dynamics and well-tempered metadynamics simulations for systems with the antagonist CP-376395 in CRF1R or CRF2R to address this issue. We found that the side chain of Tyr6.63 forms a hydrogen bond with the residue remote from the binding pocket, which allows Tyr6.63 to adopt different conformations in the two receptors and results in the presence or absence of a bottleneck controlling the antagonist binding to or dissociation from the receptors. The rotameric switch of the side chain of Tyr3566.63 allows the breaking down of the bottleneck and is a perquisite for the dissociation of CP-376395 from CRF1R.

  4. Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease

    Directory of Open Access Journals (Sweden)

    Sherin Saheera

    2017-10-01

    Full Text Available Background Cardiac stem cells (CSCs play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated. Methods To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats. Results Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment. Discussion As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of

  5. Pharmacological characterization of BR-A-657, a highly potent nonpeptide angiotensin II receptor antagonist.

    Science.gov (United States)

    Chi, Yong Ha; Lee, Joo Han; Kim, Je Hak; Tan, Hyun Kwang; Kim, Sang Lin; Lee, Jae Yeol; Rim, Hong-Kun; Paik, Soo Heui; Lee, Kyung-Tae

    2013-01-01

    The pharmacological profile of BR-A-657, 2-n-butyl-5-dimethylamino-thiocarbonyl-methyl-6-methyl-3-{[2-(1H-tetrazole-5-yl)biphenyl-4-yl]methyl}-pyrimidin-4(3H)-one, a new nonpeptide AT1-selective angiotensin receptor antagonist, has been investigated in a variety of in vitro and in vivo experimental models. In the present study, BR-A-657 displaced [(125)I][Sar(1)-Ile(8)]angiotensin II (Ang II) from its specific binding sites to AT1 subtype receptors in membrane fractions of HEK-293 cells with an IC50 of 0.16 nM. In a functional assay using isolated rabbit thoracic aorta, BR-A-657 inhibited the contractile response to Ang II (pD'2: 9.15) with a significant reduction in the maximum. In conscious rats, BR-A-657 (0.01, 0.1, 1 mg/kg; intravenously (i.v.)) dose-dependently antagonized Ang II-induced pressor responses. In addition, BR-A-657 dose-dependently decreased mean arterial pressure in furosemide-treated rats and renal hypertensive rats. Moreover, BR-A-657 given orally at 1 and 3 mg/kg reduced blood pressure in conscious renal hypertensive rats. Taken together, these findings indicate that BR-A-657 is a potent and specific antagonist of Ang II at the AT1 receptor subtype, and reveal the molecular basis responsible for the marked lowering of blood pressure in conscious rats.

  6. Effect of corticotropin-releasing factor receptor antagonist on psychologically suppressed masculine sexual behavior in rats.

    Science.gov (United States)

    Miwa, Yoshiji; Nagase, Keiko; Oyama, Nobuyuki; Akino, Hironobu; Yokoyama, Osamu

    2011-03-01

    Corticotropin-releasing factor (CRF) coordinates various responses of the body to stress, and CRF receptors are important targets of treatment for stress-related disorders. To investigate the effect of a nonselective CRF receptor antagonist, astressin, on suppression of masculine sexual behavior by psychological stress in rats. First, we investigated the influence of psychological stress, induced 2 hours per day for three consecutive days, on sexual behavior. Then, rats were divided into 4 groups: a control group, an astressin administration group (A), a psychological stress loading group (PS), and a psychological stress loading and astressin administration group (PS + A). The rats were exposed to sham or psychological stress for three consecutive days. After the last stress loading, the rats were injected with vehicle or astressin, and their sexual behavior was observed. We also measured serum levels of adrenocorticotropic hormone (ACTH). The effects of astressin on sexual behavior and serum levels of ACTH in rats affected by psychological stress were determined. Sexual behavior was reduced after psychological stress loading. The PS rats had significantly longer mount, intromission, and ejaculation latencies and lower ejaculation frequency than did the control, A, and PS + A rats. The intromission latency and ejaculation frequency in the PS + A rats did not achieve the level observed in the controls. There was no significant difference in these parameters between the control and A rats. Serum ACTH levels were significantly lower in PS + A rats than in PS rats. Psychologically suppressed masculine sexual behavior could be partially recovered with astressin administration in rats. These data provide a rationale for the further study of CRF receptor antagonists as novel agents for treating psychological sexual disorders. © 2010 International Society for Sexual Medicine.

  7. P2Y1 receptor antagonists mitigate oxygen and glucose deprivation‑induced astrocyte injury.

    Science.gov (United States)

    Guo, Hui; Liu, Zhong-Qiang; Zhou, Hui; Wang, Zhi-Ling; Tao, Yu-Hong; Tong, Yu

    2018-01-01

    The aim of the present study was to elucidate the effects of blocking the calcium signaling pathway of astrocytes (ASs) on oxygen and glucose deprivation (OGD)‑induced AS injury. The association between the changes in the concentrations of AS‑derived transmitter ATP and glutamic acid, and the changes in calcium signaling under the challenge of OGD were investigated. The cortical ASs of Sprague Dawley rats were cultured to establish the OGD models of ASs. The extracellular concentrations of ATP and glutamic acid in the normal group and the OGD group were detected, and the intracellular concentration of calcium ions (Ca2+) was detected. The effects of 2'‑deoxy‑N6‑methyl adenosine 3', 5'‑diphosphate diammonium salt (MRS2179), a P2Y1 receptor antagonist, on the release of calcium and glutamic acid of ASs under the condition of OGD were observed. The OGD challenge induced the release of glutamic acid and ATP by ASs in a time‑dependent manner, whereas elevation in the concentration of glutamic acid lagged behind that of the ATP and Ca2+. The concentration of Ca2+ inside ASs peaked 16 h after OGD, following which the concentration of Ca2+ was decreased. The effects of elevated release of glutamic acid by ASs when challenged by OGD may be blocked by MRS2179, a P2Y1 receptor antagonist. Furthermore, MRS2179 may significantly mitigate OGD‑induced AS injury and increase cell survival. The ASs of rats cultured in vitro expressed P2Y1 receptors, which may inhibit excessive elevation in the concentration of intracellular Ca2+. Avoidance of intracellular calcium overload and the excessive release of glutamic acid may be an important reason why MRS2179 mitigates OGD‑induced AS injury.

  8. Administration of an oxytocin receptor antagonist attenuates sexual motivation in male rats.

    Science.gov (United States)

    Blitzer, D S; Wells, T E; Hawley, W R

    2017-08-01

    In male rats, oxytocin impacts both sexual arousal and certain types of consummatory sexual behaviors. However, the role of oxytocin in the motivational aspects of sexual behavior has received limited attention. Given the role that oxytocin signaling plays in consummatory sexual behaviors, it was hypothesized that pharmacological attenuation of oxytocin signaling would reduce sexual motivation in male rats. Sexually experienced Long-Evans male rats were administered either an oxytocin receptor antagonist (L368,899 hydrochloride; 1mg/kg) or vehicle control into the intraperitoneal cavity 40min prior to placement into the center chamber of a three-chambered arena designed to assess sexual motivation. During the 20-minute test, a sexually experienced stimulus male rat and a sexually receptive stimulus female rat were separately confined to smaller chambers that were attached to the larger end chambers of the arena. However, physical contact between test and stimulus rats was prevented by perforated dividers. Immediately following the sexual motivation test, test male rats were placed with a sexually receptive female to examine consummatory sexual behaviors. Although both drug and vehicle treated rats exhibited a preference for the female, treatment with an oxytocin receptor antagonist decreased the amount of time spent with the female. There were no differences between drug and vehicle treated rats in either general activity, exploratory behaviors, the amount of time spent near the stimulus male rat, or consummatory sexual behaviors. Extending previous findings, these results indicate that oxytocin receptors are involved in sexual motivation in male rats. Copyright © 2017 Elsevier Inc. All rights reserved.

  9. MIA PaCa-2 and PANC-1 - pancreas ductal adenocarcinoma cell lines with neuroendocrine differentiation and somatostatin receptors.

    Science.gov (United States)

    Gradiz, Rui; Silva, Henriqueta C; Carvalho, Lina; Botelho, Maria Filomena; Mota-Pinto, Anabela

    2016-02-17

    Studies using cell lines should always characterize these cells to ensure that the results are not distorted by unexpected morphological or genetic changes possibly due to culture time or passage number. Thus, the aim of this study was to describe those MIA PaCa-2 and PANC-1 cell line phenotype and genotype characteristics that may play a crucial role in pancreatic cancer therapeutic assays, namely neuroendocrine chemotherapy and peptide receptor radionuclide therapy. Epithelial, mesenchymal, endocrine and stem cell marker characterization was performed by immunohistochemistry and flow cytometry, and genotyping by PCR, gene sequencing and capillary electrophoresis. MIA PaCa-2 (polymorphism) expresses CK5.6, AE1/AE3, E-cadherin, vimentin, chromogranin A, synaptophysin, SSTR2 and NTR1 but not CD56. PANC-1 (pleomorphism) expresses CK5.6, MNF-116, vimentin, chromogranin A, CD56 and SSTR2 but not E-cadherin, synaptophysin or NTR1. MIA PaCA-1 is CD24(-), CD44(+/++), CD326(-/+) and CD133/1(-), while PANC-1 is CD24(-/+), CD44(+), CD326(-/+) and CD133/1(-). Both cell lines have KRAS and TP53 mutations and homozygous deletions including the first 3 exons of CDKN2A/p16(INK4A), but no SMAD4/DPC4 mutations or microsatellite instability. Both have neuroendocrine differentiation and SSTR2 receptors, precisely the features making them suitable for the therapies we propose to assay in future studies.

  10. Crystal structure of a prolactin receptor antagonist bound to the extracellular domain of the prolactin receptor

    DEFF Research Database (Denmark)

    Svensson, L Anders; Bondensgaard, Kent; Nørskov-Lauritsen, Leif

    2008-01-01

    The crystal structure of the complex between an N-terminally truncated G129R human prolactin (PRL) variant and the extracellular domain of the human prolactin receptor (PRLR) was determined at 2.5A resolution by x-ray crystallography. This structure represents the first experimental structure...... studies, the structural data imply that the definition of PRL binding site 1 should be extended to include residues situated in the N-terminal part of loop 1 and in the C terminus. Comparison of the structure of the receptor-bound PRL variant with the structure reported for the unbound form of a similar...... scale rearrangements and structuring occur in the flexible N-terminal part of loop 1. Hydrogen exchange mass spectrometry data imply that the dynamics of the four-helix bundle in solution generally become stabilized upon receptor interaction at binding site 1....

  11. The anticancer estrogen receptor antagonist tamoxifen impairs consolidation of inhibitory avoidance memory through estrogen receptor alpha.

    Science.gov (United States)

    Lichtenfels, Martina; Dornelles, Arethuza da Silva; Petry, Fernanda Dos Santos; Blank, Martina; de Farias, Caroline Brunetto; Roesler, Rafael; Schwartsmann, Gilberto

    2017-11-01

    Over two-thirds of women with breast cancer have positive tumors for hormone receptors, and these patients undergo treatment with endocrine therapy, tamoxifen being the most widely used agent. Despite being very effective in breast cancer treatment, tamoxifen is associated with side effects that include cognitive impairments. However, the specific aspects and mechanisms underlying these impairments remain to be characterized. Here, we have investigated the effects of tamoxifen and interaction with estrogen receptors on formation of memory for inhibitory avoidance conditioning in female rats. In the first experiment, Wistar female rats received a single oral dose of tamoxifen (1, 3, or 10 mg/kg) or saline by gavage immediately after training and were tested for memory consolidation 24 h after training. In the second experiment, rats received a single dose of 1 mg/kg tamoxifen or saline by gavage 3 h after training and were tested 24 h after training for memory consolidation. In the third experiment, rats received a subcutaneous injection with estrogen receptor α agonist or estrogen receptor beta agonist 30 min before the training. After training, rats received a single oral dose of tamoxifen 1 mg/kg or saline and were tested 24 h after training. In the fourth experiment, rats were trained and tested 24 h later. Immediately after test, rats received a single dose of tamoxifen (1 mg/kg) or saline by gavage and were given four additional daily test trials followed by a re-instatement. Tamoxifen at 1 mg/kg impaired memory consolidation when given immediately after training and the estrogen receptor alpha agonist improved the tamoxifen-related memory impairment. Moreover, tamoxifen impairs memory consolidation of the test. These findings indicate that estrogen receptors regulate the early phase of memory consolidation and the effects of tamoxifen on memory consolidation.

  12. Somatostatin receptor expression in the human spleen - Answer to an enigma by ex-vivo and in-vitro autoradiography after 177Lu-DOTA-octreotate administration

    International Nuclear Information System (INIS)

    Melis, M.; Swart, J. de; Groen, H.C.; Konijnenberg, M.W.; Van der Graaf, L.M.; Kaemmerer, D.; Kulkami, H.R.; Baum, R.P.; Lupp, A.; Saenger, J.; Jong, M. de

    2015-01-01

    Full text of publication follows. Aim: radiolabelled somatostatin analogues are being used for diagnostic and therapeutic (PRRT) purposes in patients with somatostatin receptor (SSTR) expressing tumours. During PRRT a significant spleen uptake may lead to radiation doses of > 20 Gy. Yet, the threshold dose for spleen radiation induced toxicity is currently unknown. Based on previous 68 Ga-DOTATOC PET/CT studies, demonstrating higher uptake in spleen than in splenosis, white pulp (WP) localization of radioactivity was suggested. This hypothesis was investigated in the current pilot study using the longer lived 177 Lu-DOTA-octreotate. Methods: a patient diagnosed with neuroendocrine neoplasm of the pancreatic tail (SUV max on 68 Ga-DOTATOC PET/CT 100.4) with liver metastasis (SUV 47.3, normal liver SUV 12.5) and uptake in the spleen (SUV 41.0) received 1 GBq 177 Lu-DOTA-octreotate. 2 h after administration whole-body planar scintigraphy and SPECT/CT of the upper abdomen was performed, followed by laparoscopic resection of the pancreatic tumour and splenectomy the next day. After spleen transport from Bad Berka to Rotterdam ex-vivo micro-SPECT of the removed spleen was acquired for 73 min using 2.5 mm diameter pinholes. Spleen fragments (∼10 * 10 * 5 mm) were either snap-frozen in liquid nitrogen or fixed in 10% formalin and paraffin embedded. Ex-vivo autoradiography of 10 μm cryo-sections was performed and serial sections were used for 111 In-DOTA-octreotate in-vitro autoradiography after decay of 177 Lu. FFPE sections were used for HE- and immunostaining for SSTR2A and cell subsets CD4 (Th-cell), CD8 (Ts-cell), CD20 (B-cell) and CD68 (macrophage). Results: 177 Lu-DOTA-octreotate scintigraphy and SPECT/CT demonstrated high uptake in the pancreatic tumor, hepatic metastasis and homogeneously in the normal spleen. High resolution micro-SPECT imaging of the isolated spleen also revealed a relatively homogeneous uptake (calculated rest activity 60 MBq 177 Lu). The

  13. Somatostatin receptor PET in neuroendocrine tumours: 68Ga-DOTA0,Tyr3-octreotide versus 68Ga-DOTA0-lanreotide

    International Nuclear Information System (INIS)

    Putzer, Daniel; Kroiss, Alexander; Waitz, Dietmar; Gabriel, Michael; Uprimny, Christian; Guggenberg, Elisabeth von; Decristoforo, Clemens; Warwitz, Boris; Virgolini, Irene Johanna; Traub-Weidinger, Tatjana; Widmann, Gerlig

    2013-01-01

    The aim of this study was to evaluate the impact of 68 Ga-labelled DOTA 0 -lanreotide ( 68 Ga-DOTA-LAN) on the diagnostic assessment of neuroendocrine tumour (NET) patients with low to moderate uptake on planar somatostatin receptor (SSTR) scintigraphy or 68 Ga-labelled DOTA 0 ,Tyr 3 -octreotide ( 68 Ga-DOTA-TOC) positron emission tomography (PET). Fifty-three patients with histologically confirmed NET and clinical signs of progressive disease, who had not qualified for peptide receptor radionuclide therapy (PRRT) on planar SSTR scintigraphy or 68 Ga-DOTA-TOC PET (n = 38) due to lack of tracer uptake, underwent 68 Ga-DOTA-LAN PET to evaluate a treatment option with 90 Y-labelled lanreotide according to the MAURITIUS trial. The included patients received 150 ± 30 MBq of each radiopharmaceutical intravenously. PET scans were acquired 60-90 min after intravenous bolus injection. Image results from both PET scans were compared head to head, focusing on the intensity of tracer uptake in terms of treatment decision. CT was used for morphologic correlation of tumour lesions. To further evaluate the binding affinities of each tracer, quantitative and qualitative values were calculated for target lesions. 68 Ga-DOTA-LAN and 68 Ga-DOTA-TOC both showed equivalent findings in 24/38 patients when fused PET/CT images were interpreted. The sensitivity, specificity and accuracy of 68 Ga-DOTA-LAN in comparison to CT were 0.63, 0.5 and 0.62 (n = 53; p 68 Ga-DOTA-TOC in comparison to CT 0.78, 0.5 and 0.76 (n = 38; p 68 Ga-DOTA-TOC showed a significantly higher maximum standardized uptake value (SUV max ) regarding the primary tumour in 25 patients (p 68 Ga-DOTA-LAN. Corresponding values of both PET scans for tumour and liver did not show any significant correlation. 68 Ga-DOTA-TOC revealed more tumour sites than 68 Ga-DOTA-LAN (106 vs 53). The tumour to background ratios for tumour and liver calculated from SUV max measurements were significantly higher for 68 Ga-DOTA-TOC than 68 Ga

  14. Effect of the selective vasopressin V2 receptor antagonists in hepatic cirrhosis patients with ascites: a meta-analysis

    Directory of Open Access Journals (Sweden)

    Shao-hui TANG

    2013-07-01

    Full Text Available Objective To evaluate the efficacy and safety of selective vasopressin V2 receptor antagonists in the treatment of hepatic cirrhosis patients with ascites. Methods PubMed, EMBASE, Web of Science, The Cochrane Central Register of Controlled Trials, Database for Chinese Technical Periodical (VIP, Chinese Journal Full-Text Database (CNKI, and Wan Fang Digital Journal Full-text Database were retrieved to collect clinical randomized controlled trials of hepatic cirrhosis with ascites treated by selective vasopressin V2 receptor antagonists. Meta analysis was performed by using Review Manager 5.0. Results Nine randomized controlled trials including 1884 patients met the inclusion criteria. Meta-analysis showed that: 1 The selective vasopressin V2 receptor antagonists were associated with a significant reduction in body weight compared with placebo (WMD=–1.98kg, 95%CI:–3.24-–0.72kg, P=0.002. Treatment with selective vasopressin V2 receptor antagonists was associated with an improvement of low serum sodium concentration compared to placebo (WMD=3.74mmol/L, 95%CI: 0.91-6.58mmol/L, P=0.01. The percentage of patients with worsening ascites was higher in the group of patients treated with placebo (RR=0.51, 95%CI: 0.34-0.77, P=0.001. 2 The amplitude of increased urine volume was obviously higher in selective vasopressin V2 receptor antagonists group than in placebo group (WMD=1437.65ml, 95%CI: 649.01-2226.30ml, P=0.0004. The difference of serum creatinine in the selective vasopressin V2 receptor antagonists group was not statistically significant compared with the control group (WMD=–3.49μmol/L, 95%CI: –12.54¬5.56μmol/L, P=0.45. 3 There was no statistical significance between the two groups in the heart rate, systolic pressure, diastolic pressure and mortality (P>0.05. The rate of other adverse reactions was higher in the selective vasopressin V2 receptor antagonists group compared with that of placebo group (P=0.003. Conclusion

  15. The angiotensin II type 1 receptor antagonist Losartan binds and activates bradykinin B2 receptor signaling

    DEFF Research Database (Denmark)

    Bonde, Marie Mi; Olsen, Kristine Boisen; Erikstrup, Niels

    2011-01-01

    The angiotensin II type 1 receptor (AT1R) blocker (ARB) Losartan has cardioprotective effects during ischemia-reperfusion injury and inhibits reperfusion arrhythmias -effects that go beyond the benefits of lowering blood pressure. The renin-angiotensin and kallikrein-kinin systems are intricately...

  16. Striatal pre- and postsynaptic profile of adenosine A(2A receptor antagonists.

    Directory of Open Access Journals (Sweden)

    Marco Orru

    2011-01-01

    Full Text Available Striatal adenosine A(2A receptors (A(2ARs are highly expressed in medium spiny neurons (MSNs of the indirect efferent pathway, where they heteromerize with dopamine D(2 receptors (D(2Rs. A(2ARs are also localized presynaptically in cortico-striatal glutamatergic terminals contacting MSNs of the direct efferent pathway, where they heteromerize with adenosine A(1 receptors (A(1Rs. It has been hypothesized that postsynaptic A(2AR antagonists should be useful in Parkinson's disease, while presynaptic A(2AR antagonists could be beneficial in dyskinetic disorders, such as Huntington's disease, obsessive-compulsive disorders and drug addiction. The aim or this work was to determine whether selective A(2AR antagonists may be subdivided according to a preferential pre- versus postsynaptic mechanism of action. The potency at blocking the motor output and striatal glutamate release induced by cortical electrical stimulation and the potency at inducing locomotor activation were used as in vivo measures of pre- and postsynaptic activities, respectively. SCH-442416 and KW-6002 showed a significant preferential pre- and postsynaptic profile, respectively, while the other tested compounds (MSX-2, SCH-420814, ZM-241385 and SCH-58261 showed no clear preference. Radioligand-binding experiments were performed in cells expressing A(2AR-D(2R and A(1R-A(2AR heteromers to determine possible differences in the affinity of these compounds for different A(2AR heteromers. Heteromerization played a key role in the presynaptic profile of SCH-442416, since it bound with much less affinity to A(2AR when co-expressed with D(2R than with A(1R. KW-6002 showed the best relative affinity for A(2AR co-expressed with D(2R than co-expressed with A(1R, which can at least partially explain the postsynaptic profile of this compound. Also, the in vitro pharmacological profile of MSX-2, SCH-420814, ZM-241385 and SCH-58261 was is in accordance with their mixed pre- and postsynaptic profile

  17. Sulforaphane is not an effective antagonist of the human pregnane X-receptor in vivo

    International Nuclear Information System (INIS)

    Poulton, Emma Jane; Levy, Lisa; Lampe, Johanna W.; Shen, Danny D.; Tracy, Julia; Shuhart, Margaret C.; Thummel, Kenneth E.; Eaton, David L.

    2013-01-01

    Sulforaphane (SFN), is an effective in vitro antagonist of ligand activation of the human pregnane and xenobiotic receptor (PXR). PXR mediated CYP3A4 up-regulation is implicated in adverse drug-drug interactions making identification of small molecule antagonists a desirable therapeutic goal. SFN is not an antagonist to mouse or rat PXR in vitro; thus, normal rodent species are not suitable as in vivo models for human response. To evaluate whether SFN can effectively antagonize ligand activation of human PXR in vivo, a three-armed, randomized, crossover trial was conducted with 24 healthy adults. The potent PXR ligand — rifampicin (300 mg/d) was given alone for 7 days in arm 1, or in daily combination with 450 μmol SFN (Broccoli Sprout extract) in arm 2; SFN was given alone in arm 3. Midazolam as an in vivo phenotype marker of CYP3A was administered before and after each treatment arm. Rifampicin alone decreased midazolam AUC by 70%, indicative of the expected increase in CYP3A4 activity. Co-treatment with SFN did not reduce CYP3A4 induction. Treatment with SFN alone also did not affect CYP3A4 activity in the cohort as a whole, although in the subset with the highest basal CYP3A4 activity there was a statistically significant increase in midazolam AUC (i.e., decrease in CYP3A4 activity). A parallel study in humanized PXR mice yielded similar results. The parallel effects of SFN between humanized PXR mice and human subjects demonstrate the predictive value of humanized mouse models in situations where species differences in ligand-receptor interactions preclude the use of a native mouse model for studying human ligand-receptor pharmacology. -- Highlights: ► The effects of SFN on PXR mediated CYP3A4 induction in humanized PXR mice and humans were examined. ► SFN had no effect on rifampicin mediated CYP3A4 induction in humans or humanized mice. ► SFN had a modest effect on basal CYP3A4 activity among subjects with higher baseline activity. ► Humanized PXR

  18. Decrement in operant performance produced by NMDA receptor antagonists in the rat: tolerance and cross-tolerance.

    Science.gov (United States)

    Dravolina, O A; Zvartau, E E; Bespalov, A Y

    2000-04-01

    Current perspectives on the clinical use of NMDA receptor antagonists infer repeated administration schedules for the management of different pathological states. The development of tolerance and cross-tolerance between different NMDA receptor antagonists may be an important factor contributing to the clinical efficacy of these drugs. The present study aimed to characterize the development of tolerance and cross-tolerance to the ability of various site-selective NMDA receptor antagonists to produce a decrement of operant responding (multiple extinction 9 s fixed-interval 1-s schedule of water reinforcement). Acute administration of D-CPPen (SDZ EAA 494; 1-5.6 mg/kg), dizocilpine (MK-801; 0.03-0.3 mg/kg), memantine (0.3-17 mg/kg), ACEA-1021 (10-56 mg/kg), and eliprodil (1-30 mg/kg) differentially affected operant responding. Both increases and decreases in response rates and accuracy of responding were observed. Repeated preexposure to D-CPPen (5.6 mg/kg, once a day for 7 days) attenuated a behavioral disruption produced by an acute challenge with D-CPPen or ACEA-1021, but potentiated the effects of dizocilpine, memantine, and eliprodil. Based on the present results, one can suggest that the repeated administration of a competitive NMDA receptor antagonist differentially affects the functional activity of various sites on NMDA receptor complex.

  19. Modulation of cytokine and cytokine receptor/antagonist by treatment with doxycycline and tetracycline in patients with dengue fever.

    Science.gov (United States)

    Castro, J E Z; Vado-Solis, I; Perez-Osorio, C; Fredeking, T M

    2011-01-01

    Dengue virus infection can lead to dengue fever (DF) or dengue hemorrhagic fever (DHF). Disease severity has been linked to an increase in various cytokine levels. In this study, we evaluated the effectiveness of doxycycline and tetracycline to modulate serum levels of IL-6, IL-1B, and TNF and cytokine receptor/receptor antagonist TNF-R1 and IL-1RA in patients with DF or DHF. Hospitalized patients were randomized to receive standard supportive care or supportive care combined with doxycycline or tetracycline therapy. Serum cytokine and cytokine receptor/antagonist levels were determined at the onset of therapy and after 3 and 7 days. Cytokine and cytokine receptor/antagonist levels were substantially elevated at day 0. IL-6, IL-1β, and TNF remained at or above day 0 levels throughout the study period in untreated patients. Treatment with tetracycline or doxycycline resulted in a significant decline in cytokine levels. Similarly, IL-1RA and TNF-R1 serum concentrations were elevated at baseline and showed a moderate increase among untreated patients. Both drugs resulted in a significant rise in IL-1Ra levels by day 3 in patients. In contrast, treatment did not affect a similar result for TNF-R1. When compared to the control group, however, a significant rise post-treatment was seen upon intragroup analysis. Further analysis demonstrated that doxycycline was significantly more effective at modulating cytokine and cytokine receptor/antagonist levels than tetracycline.

  20. Effects of melatonin and its receptor antagonist on retinal pigment epithelial cells against hydrogen peroxide damage

    Science.gov (United States)

    Rosen, Richard B.; Hu, Dan-Ning; Chen, Min; McCormick, Steven A.; Walsh, Joseph

    2012-01-01

    Purpose Recently, we reported finding that circulating melatonin levels in age-related macular degeneration patients were significantly lower than those in age-matched controls. The purpose of this study was to investigate the hypothesis that melatonin deficiency may play a role in the oxidative damage of the retinal pigment epithelium (RPE) by testing the protective effect of melatonin and its receptor antagonist on RPE cells exposed to H2O2 damage. Methods Cultured human RPE cells were subjected to oxidative stress induced by 0.5 mM H2O2. Cell viability was measured using the microculture tetrazoline test (MTT) assay. Cells were pretreated with or without melatonin for 24 h. Luzindole (50 μM), a melatonin membrane-receptor antagonist, was added to the culture 1 h before melatonin to distinguish direct antioxidant effects from indirect receptor-dependent effects. All tests were performed in triplicate. Results H2O2 at 0.5 mM decreased cell viability to 20% of control levels. Melatonin showed dose-dependent protective effects on RPE cells against H2O2. Cell viability of RPE cells pretreated with 10−10, 10−8, 10−6, and 10−4 M melatonin for 24 h was 130%, 160%, 187%, and 230% of cells treated with H2O2 alone (all p<0.05). Using cells cultured without H2O2 as the control, cell viability of cells treated with H2O2 after pretreatment with 10−10-10−4 M melatonin was still significantly lower than that of the controls, suggesting that melatonin significantly decreased but did not completely abolish the in vitro cytotoxic effects of H2O2. Luzindole completely blocked melatonin’s protective effects at low concentrations of melatonin (10−10-10−8 M) but not at high concentrations (10−6-10−4 M). Conclusions Melatonin has a partial protective effect on RPE cells against H2O2 damage across a wide range of concentrations (10−10-10−4 M). This protective effect occurs through the activation of melatonin membrane receptors at low concentrations (10−10

  1. The effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine, and antagonists yohimbine and efaroxan, on the spinal cholinergic receptor system in the rat

    DEFF Research Database (Denmark)

    Abelson, Klas S P; Höglund, A Urban

    2004-01-01

    Cholinergic agonists produce spinal antinociception via mechanisms involving an increased release of intraspinal acetylcholine. The cholinergic receptor system interacts with several other receptor types, such as alpha2-adrenergic receptors. To fully understand these interactions, the effects...... of various receptor ligands on the cholinergic system must be investigated in detail. This study was initiated to investigate the effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine and the alpha2-adrenergic receptor antagonists yohimbine and efaroxan on spinal cholinergic receptors......, all ligands possessed affinity for nicotinic receptors. Clonidine and yohimbine binding was best fit to a one site binding curve and rilmenidine and efaroxan to a two site binding curve. The present study demonstrates that the tested alpha2-adrenergic receptor ligands affect intraspinal acetylcholine...

  2. Topical interleukin 1 receptor antagonist for treatment of dry eye disease: a randomized clinical trial.

    Science.gov (United States)

    Amparo, Francisco; Dastjerdi, Mohammad H; Okanobo, Andre; Ferrari, Giulio; Smaga, Leila; Hamrah, Pedram; Jurkunas, Ula; Schaumberg, Debra A; Dana, Reza

    2013-06-01

    The immunopathogenic mechanisms of dry eye disease (DED), one of the most common ophthalmic conditions, is incompletely understood. Data from this prospective, double-masked, randomized trial demonstrate that targeting interleukin 1 (IL-1) by topical application of an IL-1 antagonist is efficacious in significantly reducing DED-related patient symptoms and corneal epitheliopathy. To evaluate the safety and efficacy of treatment with the topical IL-1 receptor antagonist anakinra (Kineret; Amgen Inc) in patients having DED associated with meibomian gland dysfunction. Prospective phase 1/2, randomized, double-masked, vehicle-controlled clinical trial. Seventy-five patients with refractory DED. Participants were randomized to receive treatment with topical anakinra, 2.5% (n = 30), anakinra, 5% (n = 15), or vehicle (1% carboxymethylcellulose) (n = 30) 3 times daily for 12 weeks. Primary outcomes were corneal fluorescein staining (CFS), complete bilateral CFS clearance, dry eye-related symptoms as measured by the Ocular Surface Disease Index, tear film breakup time, and meibomian gland secretion quality. Topical anakinra was well tolerated compared with vehicle, with no reports of serious adverse reactions attributable to the therapy. After 12 weeks of therapy, participants treated with anakinra, 2.5%, achieved a 46% reduction in their mean CFS score (P = .12 compared with vehicle and P treatment with anakinra, 2.5%, and treatment with anakinra, 5%, led to significant reductions in symptoms of 30% and 35%, respectively (P = .02 and P = .01, respectively, compared with vehicle); treatment with vehicle led to a 5% reduction in symptoms. Treatment with topical anakinra, 2.5%, for 12 weeks was safe and significantly reduced symptoms and corneal epitheliopathy in patients with DED. These data suggest that the use of an IL-1 antagonist may have a role as a novel therapeutic option for patients with DED. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00681109.

  3. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium.

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2012-02-01

    BACKGROUND: Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. RESULTS: Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. CONCLUSION: Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  4. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium

    LENUS (Irish Health Repository)

    Dooley, Ruth

    2011-08-22

    Abstract Background Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. Results Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. Conclusion Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  5. Crystal structure of the[mu]-opioid receptor bound to a morphinan antagonist

    Energy Technology Data Exchange (ETDEWEB)

    Manglik, Aashish; Kruse, Andrew C.; Kobilka, Tong Sun; Thian, Foon Sun; Mathiesen, Jesper M.; Sunahara, Roger K.; Pardo, Leonardo; Weis, William I.; Kobilka, Brian K.; Granier, Sébastien (Michigan-Med); (Stanford-MED); (UAB, Spain)

    2012-06-27

    Opium is one of the world's oldest drugs, and its derivatives morphine and codeine are among the most used clinical drugs to relieve severe pain. These prototypical opioids produce analgesia as well as many undesirable side effects (sedation, apnoea and dependence) by binding to and activating the G-protein-coupled {mu}-opioid receptor ({mu}-OR) in the central nervous system. Here we describe the 2.8 {angstrom} crystal structure of the mouse {mu}-OR in complex with an irreversible morphinan antagonist. Compared to the buried binding pocket observed in most G-protein-coupled receptors published so far, the morphinan ligand binds deeply within a large solvent-exposed pocket. Of particular interest, the {mu}-OR crystallizes as a two-fold symmetrical dimer through a four-helix bundle motif formed by transmembrane segments 5 and 6. These high-resolution insights into opioid receptor structure will enable the application of structure-based approaches to develop better drugs for the management of pain and addiction.

  6. Gene expression profiling of the androgen receptor antagonists flutamide and vinclozolin in zebrafish (Danio rerio) gonads

    International Nuclear Information System (INIS)

    Martinovic-Weigelt, Dalma; Wang Ronglin; Villeneuve, Daniel L.; Bencic, David C.; Lazorchak, Jim; Ankley, Gerald T.

    2011-01-01

    The studies presented in this manuscript focus on characterization of transcriptomic responses to anti-androgens in zebrafish (Danio rerio). Research on the effects of anti-androgens in fish has been characterized by a heavy reliance on apical endpoints, and molecular mechanisms of action (MOA) of anti-androgens remain poorly elucidated. In the present study, we examined effects of a short term exposure (24-96 h) to the androgen receptor antagonists flutamide (FLU) and vinclozolin (VZ) on gene expression in gonads of sexually mature zebrafish, using commercially available zebrafish oligonucleotide microarrays (4 x 44 K platform). We found that VZ and FLU potentially impact reproductive processes via multiple pathways related to steroidogenesis, spermatogenesis, and fertilization. Observed changes in gene expression often were shared by VZ and FLU, as demonstrated by overlap in differentially-expressed genes and enrichment of several common key pathways including: (1) integrin and actin signaling, (2) nuclear receptor 5A1 signaling, (3) fibroblast growth factor receptor signaling, (4) polyamine synthesis, and (5) androgen synthesis. This information should prove useful to elucidating specific mechanisms of reproductive effects of anti-androgens in fish, as well as developing biomarkers for this important class of endocrine-active chemicals.

  7. A novel thromboxane receptor antagonist, nstpbp5185, inhibits platelet aggregation and thrombus formation in animal models.

    Science.gov (United States)

    Huang, Shiu-Wen; Kuo, Heng-Lan; Hsu, Ming-Tsung; Tseng, Yufeng Jane; Lin, Shu-Wha; Kuo, Sheng-Chu; Peng, Hui-Chin; Lien, Jin-Cherng; Huang, Tur-Fu

    2016-08-01

    A novel benzimidazole derivative, nstpbp5185, was discovered through in vitro and in vivo evaluations for antiplatelet activity. Thromaboxane receptor (TP) is important in vascular physiology, haemostasis and pathophysiological thrombosis. Nstpbp5185 concentration-dependently inhibited human platelet aggregation caused by collagen, arachidonic acid and U46619. Nstpbp5185 caused a right-shift of the concentration-response curve of U46619 and competitively inhibited the binding of 3H-SQ-29548 to TP receptor expressed on HEK-293 cells, with an IC50 of 0.1 µM, indicating that nstpbp5185 is a TP antagonist. In murine thrombosis models, nstpbp5185 significantly prolonged the latent period in triggering platelet plug formation in mesenteric and FeCl3-induced thrombi formation, and increased the survival rate in pulmonary embolism model with less bleeding than aspirin. This study suggests nstpbp5185, an orally selective anti-thrombotic agent, acting through blockade of TXA2 receptor, may be efficacious for prevention or treatment of pathologic thrombosis.

  8. Development and labeling of EP-00652218 analogues, NK1 receptors antagonist, for PET and SPECT imaging

    International Nuclear Information System (INIS)

    Bagot-Gueret, C.

    2001-12-01

    The aim of this work was the synthesis and radiosynthesis of compounds labelled either with a positron emitter (fluorine-18, t 1/2 = 109 minutes) or with a gamma emitter (iodine-123, t 1/2 = 16.2 hours), for Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT) studies. EP-00652218 is a novel potent antagonist, with a sub-nano-molar affinity towards the NK 1 receptors. In order to develop ligands that could be used either in PET or SPECT, we undertook the synthesis of poly-halogenated analogues of EP-00652218. Compound 17 was synthesized through two different synthetic pathways. A series of original compounds has been obtained from compound 17 by halogen exchanges on the naphthyridone or the benzene ring. These molecules were tested to determine their in vitro affinity towards NK 1 receptors. Compound 21 was labelled with fluorine-18 in 135 minutes and with a 20% radiochemical yield. Compound 26 was radioiodinated following reaction with Na 125 I (t 1/2 = 60.14 days) in a 18% radiochemical yield. Despite expectation, these analogues of EP-00652218 exhibited an insufficient affinity for NK 1 receptors (IC 50 = 10 -7 M) and thus unlikely usable for in vivo studies with PET and SPECT. (author)

  9. Identification of VDR Antagonists among Nuclear Receptor Ligands Using Virtual Screening

    Directory of Open Access Journals (Sweden)

    Kelly Teske

    2014-04-01

    Full Text Available Herein, we described the development of two virtual screens to identify new vitamin D receptor (VDR antagonists among nuclear receptor (NR ligands. Therefore, a database of 14330 nuclear receptor ligands and their NR affinities was assembled using the online available “Binding Database.” Two different virtual screens were carried out in conjunction with a reported VDR crystal structure applying a stringent and less stringent pharmacophore model to filter docked NR ligand conformations. The pharmacophore models were based on the spatial orientation of the hydroxyl functionalities of VDR's natural ligands 1,25(OH2D3 and 25(OH2D3. The first virtual screen identified 32 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. All but nordihydroguaiaretic acid (NDGA are VDR ligands, which inhibited the interaction between VDR and coactivator peptide SRC2-3 with an IC50 value of 15.8 μM. The second screen identified 162 NR ligands with a calculated free energy of VDR binding of more than -6.0 kJ/mol. More than half of these ligands were developed to bind VDR followed by ERα/β ligands (26%, TRα/β ligands (7%, and LxRα/β ligands (7%. The binding between VDR and ERα ligand H6036 as well as TRα/β ligand triiodothyronine and a homoserine analog thereof was confirmed by fluorescence polarization.

  10. Gene expression profiling of the androgen receptor antagonists flutamide and vinclozolin in zebrafish (Danio rerio) gonads.

    Science.gov (United States)

    Martinović-Weigelt, Dalma; Wang, Rong-Lin; Villeneuve, Daniel L; Bencic, David C; Lazorchak, Jim; Ankley, Gerald T

    2011-01-25

    The studies presented in this manuscript focus on characterization of transcriptomic responses to anti-androgens in zebrafish (Danio rerio). Research on the effects of anti-androgens in fish has been characterized by a heavy reliance on apical endpoints, and molecular mechanisms of action (MOA) of anti-androgens remain poorly elucidated. In the present study, we examined effects of a short term exposure (24-96h) to the androgen receptor antagonists flutamide (FLU) and vinclozolin (VZ) on gene expression in gonads of sexually mature zebrafish, using commercially available zebrafish oligonucleotide microarrays (4×44K platform). We found that VZ and FLU potentially impact reproductive processes via multiple pathways related to steroidogenesis, spermatogenesis, and fertilization. Observed changes in gene expression often were shared by VZ and FLU, as demonstrated by overlap in differentially-expressed genes and enrichment of several common key pathways including: (1) integrin and actin signaling, (2) nuclear receptor 5A1 signaling, (3) fibroblast growth factor receptor signaling, (4) polyamine synthesis, and (5) androgen synthesis. This information should prove useful to elucidating specific mechanisms of reproductive effects of anti-androgens in fish, as well as developing biomarkers for this important class of endocrine-active chemicals. 2010 Elsevier B.V. All rights reserved.

  11. Gene expression profiling of the androgen receptor antagonists flutamide and vinclozolin in zebrafish (Danio rerio) gonads

    Energy Technology Data Exchange (ETDEWEB)

    Martinovic-Weigelt, Dalma, E-mail: dalma@stthomas.edu [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States); University of St. Thomas, 2115 Summit Ave, Saint Paul, MN 55105 (United States); Wang Ronglin [US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26W. Martin Luther King Dr., Cincinnati, OH 45268 (United States); Villeneuve, Daniel L. [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States); Bencic, David C.; Lazorchak, Jim [US Environmental Protection Agency, Office of Research and Development, National Exposure Research Laboratory, Ecological Exposure Research Division, 26W. Martin Luther King Dr., Cincinnati, OH 45268 (United States); Ankley, Gerald T. [US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804 (United States)

    2011-01-25

    The studies presented in this manuscript focus on characterization of transcriptomic responses to anti-androgens in zebrafish (Danio rerio). Research on the effects of anti-androgens in fish has been characterized by a heavy reliance on apical endpoints, and molecular mechanisms of action (MOA) of anti-androgens remain poorly elucidated. In the present study, we examined effects of a short term exposure (24-96 h) to the androgen receptor antagonists flutamide (FLU) and vinclozolin (VZ) on gene expression in gonads of sexually mature zebrafish, using commercially available zebrafish oligonucleotide microarrays (4 x 44 K platform). We found that VZ and FLU potentially impact reproductive processes via multiple pathways related to steroidogenesis, spermatogenesis, and fertilization. Observed changes in gene expression often were shared by VZ and FLU, as demonstrated by overlap in differentially-expressed genes and enrichment of several common key pathways including: (1) integrin and actin signaling, (2) nuclear receptor 5A1 signaling, (3) fibroblast growth factor receptor signaling, (4) polyamine synthesis, and (5) androgen synthesis. This information should prove useful to elucidating specific mechanisms of reproductive effects of anti-androgens in fish, as well as developing biomarkers for this important class of endocrine-active chemicals.

  12. Purinergic receptor antagonists inhibit odorant-mediated CREB phosphorylation in sustentacular cells of mouse olfactory epithelium

    Directory of Open Access Journals (Sweden)

    Hatt Hanns

    2011-08-01

    Full Text Available Abstract Background Extracellular nucleotides have long been known to play neuromodulatory roles and to be involved in intercellular signalling. In the olfactory system, ATP is released by olfactory neurons, and exogenous ATP can evoke an increase in intracellular calcium concentration in sustentacular cells, the nonneuronal supporting cells of the olfactory epithelium. Here we investigate the hypothesis that olfactory neurons communicate with sustentacular cells via extracellular ATP and purinergic receptor activation. Results Here we show that exposure of mice to a mixture of odorants induced a significant increase in the levels of the transcription factor CREB phosphorylated at Ser-133 in the nuclei of both olfactory sensory neurons and sustentacular cells. This activation was dependent on adenylyl cyclase III-mediated olfactory signaling and on activation of P2Y purinergic receptors on sustentacular cells. Purinergic receptor antagonists inhibited odorant-dependent CREB phosphorylation specifically in the nuclei of the sustentacular cells. Conclusion Our results point to a possible role for extracellular nucleotides in mediating intercellular communication between the neurons and sustentacular cells of the olfactory epithelium in response to odorant exposure. Maintenance of extracellular ionic gradients and metabolism of noxious chemicals by sustentacular cells may therefore be regulated in an odorant-dependent manner by olfactory sensory neurons.

  13. NMDA receptor antagonist-enhanced high frequency oscillations: are they generated broadly or regionally specific?

    Science.gov (United States)

    Olszewski, Maciej; Dolowa, Wioleta; Matulewicz, Pawel; Kasicki, Stefan; Hunt, Mark J

    2013-12-01

    Systemic administration of NMDA receptor antagonists, used to model schizophrenia, increase the power of high-frequency oscillations (130-180Hz, HFO) in a variety of neuroanatomical and functionally distinct brain regions. However, it is unclear whether HFO are independently and locally generated or instead spread from a distant source. To address this issue, we used local infusion of tetrodotoxin (TTX) to distinct brain areas to determine how accurately HFO recorded after injection of NMDAR antagonists reflect the activity actually generated at the electrode tip. Changes in power were evaluated in local field potentials (LFPs) recorded from the nucleus accumbens (NAc), prefrontal cortex and caudate and in electrocorticograms (ECoGs) from visual and frontal areas. HFO recorded in frontal and visual cortices (ECoGs) or in the prefrontal cortex, caudate (LFPs) co-varied in power and frequency with observed changes in the NAc. TTX infusion to the NAc immediately and profoundly reduced the power of accumbal HFO which correlated with changes in HFO recorded in distant cortical sites. In contrast, TTX infusion to the prefrontal cortex did not change HFO power recorded locally, although gamma power was reduced. A very similar result was found after TTX infusion to the caudate. These findings raise the possibility that the NAc is an important neural generator. Our data also support existing studies challenging the idea that high frequencies recorded in LFPs are necessarily generated at the recording site. Copyright © 2013 Elsevier B.V. and ECNP. All rights reserved.

  14. Novel 2-aminotetralin and 3-aminochroman derivatives as selective serotonin 5-HT7 receptor agonists and antagonists.

    Science.gov (United States)

    Holmberg, Pär; Sohn, Daniel; Leideborg, Robert; Caldirola, Patrizia; Zlatoidsky, Pavel; Hanson, Sverker; Mohell, Nina; Rosqvist, Susanne; Nordvall, Gunnar; Johansson, Anette M; Johansson, Rolf

    2004-07-29

    The understanding of the physiological role of the G-protein coupled serotonin 5-HT(7) receptor is largely rudimentary. Therefore, selective and potent pharmacological tools will add to the understanding of serotonergic effects mediated through this receptor. In this report, we describe two compound classes, chromans and tetralins, encompassing compounds with nanomolar affinity for the 5-HT(7) receptor and with good selectivity. Within theses classes, we have discovered both agonists and antagonists that can be used for further understanding of the pharmacology of the 5-HT(7) receptor.

  15. OctreoScan 111 for imaging of a somatostatin receptor-positive islet cell tumor in rat

    International Nuclear Information System (INIS)

    Bruns, C.; Stolz, B.; Albert, R.; Marbach, P.; Pless, J.

    1993-01-01

    We report here the in vitro characterization of SDZ 215-811 and the in vivo imaging of a islet cell tumor gown in rats using [ 111 In]SDZ 215-811. In vitro autoradiographies revelaed a high density of SRIF receptors on the pancreatic tumor tissue. As early as 5 min after intravenous injection of [ 111 In]SDZ 215-811 into tumour-bearing rats, the tumors were clearly localized by gamma-camera scintigraphy. Even 24 h post injection, the islet cell tumor was still detectable. The radioligand was mainly cleared from the circulation via the Kidneys, with a rapid α-phase (t 1/2 =5.6 min) and a slow elimination phase (t 1/2 =7.3 h). Biodistribution studies revealed a relatively high accumulation of radioactivity in the kidneys, but low uptake into the liver and the intestine. High uptake of [ 111 In]SDZ 215-811 was observed for the tumor tissue (0.92±0.07% ID/g; 1 h post injection). Interestingly, a tumor load of 0.14±0.01% ID/g was still measured after 24 h. The tumor/blood ratio was 4.93 after 24 h, indicating specific accumulation of radioactivity in the islet cell tumour. [ 111 In]SDZ 215-811 appears to be sensitive and specific ligand for SRIF receptorpositive tumors and offers an easy procedure for scintigraphic imaging of such tumors in man. (orig.)

  16. Interleukin-1B and Interleukin-1 Receptor Antagonist in Patients with Helicobacter pylori Associated Diseases

    Directory of Open Access Journals (Sweden)

    Elizaveta S. Ageeva, PhD

    2012-06-01

    Full Text Available The ethnic people of the Republic of Khakassia (the Khakas with ulcer disease show a significant T-cell activation and humoral immune response when compared with the Europoids. The reasons for such differences could be due to certain ethno-specific allelic variants of the interleukins, which considerably change the degree of cytokine expression. The aim was to study the peculiarities of the association of the interleukin-1 (IL-1 gene polymorphisms and interleukin-1 receptor antagonist (IL-1Ra. Patients with chronic gastritis and ulcer disease were examined using the restriction analysis method. The most wide-spread allelic variants among the Khakas were discovered to be С�� IL-1β and R4R4 IL-1Ra. In this study, we suggest the necessity to define the population’s risk and the protective genotypes that promote Helicobacter pylori-associated ulcer disease among the Khakas people.

  17. Cardiometabolic effects of genetic upregulation of the interleukin 1 receptor antagonist

    DEFF Research Database (Denmark)

    2015-01-01

    BACKGROUND: To investigate potential cardiovascular and other effects of long-term pharmacological interleukin 1 (IL-1) inhibition, we studied genetic variants that produce inhibition of IL-1, a master regulator of inflammation. METHODS: We created a genetic score combining the effects of alleles...... of two common variants (rs6743376 and rs1542176) that are located upstream of IL1RN, the gene encoding the IL-1 receptor antagonist (IL-1Ra; an endogenous inhibitor of both IL-1α and IL-1β); both alleles increase soluble IL-1Ra protein concentration. We compared effects on inflammation biomarkers...... of this genetic score with those of anakinra, the recombinant form of IL-1Ra, which has previously been studied in randomised trials of rheumatoid arthritis and other inflammatory disorders. In primary analyses, we investigated the score in relation to rheumatoid arthritis and four cardiometabolic diseases (type...

  18. The linkage between Churg-Strauss syndrome and leukotriene receptor antagonists: fact or fiction?

    Science.gov (United States)

    McDanel, Deanna L; Muller, Barbara A

    2005-01-01

    Epidemiologic evidence has shown that the worldwide prevalence of asthma is increasing. The leukotriene receptor antagonists (LTRAs) represent a new class of therapy for asthma. They have been developed in the last decade and play a pivotal steroid-sparing role in treating the inflammatory component of asthma. Consequently, reports of Churg-Strauss syndrome (CSS), a rare form of systemic vasculitis, have been recognized as a potential side effect in individuals with moderate to severe asthma on LTRA therapy. The serious nature of this disorder is worthy of prompt recognition by clinicians and aggressive therapy to avoid the subsequent longstanding effects of vasculitis. To validate the postulated linkage between the LTRAs and CSS, this review comprehensively evaluates reported cases in the literature and supports a pathophysiological relationship between the LTRAs and the development of CSS. PMID:18360552

  19. Effects of the kappa opioid receptor antagonist MR-2266-BS on the acquisition of ethanol preference

    Energy Technology Data Exchange (ETDEWEB)

    Sandi, C.; Borrell, J.; Guaza, C. (Cajal Institute, Madrid (Spain))

    1990-01-01

    Using a paradigm by which rats forced to drink a weak ethanol solution develop ethanol preference in consecutive retention testing days, the effects of the administration of the kappa opioid antagonist MR-2266-BS, prior to or after the forced ethanol session, were studied. Pre-conditioning subcutaneous (s.c.) administration of 1 mg/kg of MR-2266-BS induced a decrease in subsequent ethanol consumption without significantly modifying the acquisition of ethanol preference. Post-conditioning administration of MR-2266-BS induced both a dose-dependent reduction in ethanol consumption and in preference throughout the three following days. The results of the present study provide further support of the involvement of kappa-type opioids on drinking behavior, and suggest that kappa receptors may be involved in the consumption and development of preference to ethanol.

  20. Lack of Association between an Interleukin-I Receptor Antagonist Gene Polymorphism and Systemic Lupus Erythematosus

    Directory of Open Access Journals (Sweden)

    Victor A. Danis

    1994-01-01

    Full Text Available Non-MHC linked genes may contribute to genetic predisposition to the development of systemic lupus erythematosus. The possibility that cytokine genes may be involved was raised by the observation of increased frequency in expression of an uncommon allele of an interleukin-I receptor antagonist gene polymorphism and SLE in a recent U.K. study. We have not been able to show any significant differences in expression of this allele in SLE patients as a whole or in any patient subgroups. Our results actually show a slight decrease in the expression of this allele in SLE patients compared with healthy controls and in SLE patients with malar rash compared with SLE patients without malar rash.

  1. Synthesis of isotopically labelled angiotensin II receptor antagonist GR138950X

    International Nuclear Information System (INIS)

    Carr, R.M.; Cable, K.M.; Newman, J.J.; Sutherland, D.R.

    1996-01-01

    Syntheses of [ 13 C] and [ 14 C]-labelled versions of angiotensin II receptor antagonist GR138950X, labelled in the imidazole carboxamide residue, are described. These involved preparation of an iodoimidazole substrate by a novel iododecarboxylation procedure, followed by cyanation with a mixture of carbon-labelled potassium cyanide and copper (l) iodide in DMF at high temperature. The preparation of a mass-labelled (M+5) version of GR138950X is also described. This involved the synthesis of an [ 13 C 3 , 15 N 2 ]-labelled imidazole from a 1,2,3-tricarbonyl compound, [ 13 C 3 ]propionaldehyde and [ 15 N]ammonia. The labelled imidazole was further elaborated into multiply-labelled GR138950X. (Author)

  2. 4-(Phenylsulfonyl)piperidines: novel, selective, and bioavailable 5-HT(2A) receptor antagonists.

    Science.gov (United States)

    Fletcher, Stephen R; Burkamp, Frank; Blurton, Peter; Cheng, Susan K F; Clarkson, Robert; O'Connor, Desmond; Spinks, Daniel; Tudge, Matthew; van Niel, Monique B; Patel, Smita; Chapman, Kerry; Marwood, Rose; Shepheard, Sara; Bentley, Graham; Cook, Gina P; Bristow, Linda J; Castro, Jose L; Hutson, Peter H; MacLeod, Angus M

    2002-01-17

    On the basis of a spirocyclic ether screening lead, a series of acyclic sulfones have been identified as high-affinity, selective 5-HT(2A) receptor antagonists. Bioavailability lacking in the parent, 1-(2-(2,4-difluorophenyl)ethyl)-4-(phenylsulfonyl)piperidine (12), was introduced by using stability toward rat liver microsomes as a predictor of bioavailability. By this means, the 4-cyano- and 4-carboxamidophenylsulfonyl derivatives 26 and 31 were identified as orally bioavailable, brain-penetrant analogues suitable for evaluation in animal models. Bioavailability was also attainable by N substitution leading to the N-phenacyl derivative 35. IKr activity detected through counterscreening was reduced to insignificant levels in vivo with the latter compound.

  3. Therapy with radiolabelled somatostatin analogs in neuroendocrine tumors

    International Nuclear Information System (INIS)

    Kunikowska, J.; Krolicki, L.

    2007-01-01

    In the 80's the discovery of somatostatin receptors expression on NET cells enabled the application of somatostatin analogues in diagnosis and therapy. Initially, 'cold' somatostatin analogs were used for therapeutical purpose, with overall good clinical response, but with minimal anti-proliferation effect. Furthermore, radiolabelled receptor-binding peptides have been shown to be an important class of radiopharmaceuticals for tumor diagnosis and therapy with minimal side-effects. Specific binding between receptor on tumor cell and peptide with beta emitting radionuclide act not only on tumor related symptoms but also on tumor cell via radiotoxic effect of beta radiation. Discoveries of next receptor combinations, allow the work over synthesis and applications of next receptors' analogs both in diagnosis and in therapy. Due to complex characteristics of NET's, the use therapeutic 'cocktail' containing the variety analogs may be of great importance. (author)

  4. Technetium-99m labeled somatostatin and analogs: synthesis, characterization and in vivo evaluation

    International Nuclear Information System (INIS)

    Amartey, J.K.

    1993-01-01

    Technetium-99m complexes of somatostatin and analogs were synthesized following the introduction of sulfhydryl groups with 2-iminothiolane (Traut's Reagent). In rats the complex was taken up by the liver, kidneys, adrenals, lungs and the pancreas. Analysis of urine samples of treated rats showed that the radiochemicals have reasonably good in vivo stability. This implies that the complexes may be potentially useful for biochemical characterization of somatostatin receptors and also in scintigraphic detection of somatostatin receptor positive tumors, especially for metastatic deposits in patients on somatostatin therapy. (Author)

  5. Screening of chemokine receptor CCR4 antagonists by capillary zone electrophoresis

    Directory of Open Access Journals (Sweden)

    Zhe Sun

    2011-11-01

    Full Text Available CC chemokine receptor 4 (CCR4 is a kind of G-protein-coupled receptor, which plays a pivotal role in allergic inflammation. The interaction between 2-(2-(4-chloro-phenyl-5-{[(naphthalen-1-ylmethyl-carbamoyl]-methyl}-4-oxo-thiazolidin-3-yl-N-(3-morpholin-4-yl-propyl-acetamide (S009 and the N-terminal extracellular tail (ML40 of CCR4 has been validated to be high affinity by capillary zone electrophoresis (CZE. The S009 is a known CCR4 antagonist. Now, a series of new thiourea derivatives have been synthesized. Compared with positive control S009, they were screened using ML40 as target by CZE to find some new drugs for allergic inflammation diseases. The synthesized compounds XJH-5, XJH-4, XJH-17 and XJH-1 displayed the interaction with ML40, but XJH-9, XJH-10, XJH-11, XJH-12, XJH-13, XJH-14, XJH-3, XJH-8, XJH-6, XJH-7, XJH-15, XJH-16 and XJH-2 did not bind to ML40. Both qualification and quantification characterizations of the binding were determined. The affinity of the four compounds was valued by the binding constant, which was similar with the results of chemotactic experiments. The established CEZ method is capable of sensitive and fast screening for a series of lactam analogs in the drug discovery for allergic inflammation diseases. Keywords: Capillary zone electrophoresis, CCR4 antagonist, 2-(2-(4-chloro-phenyl-5-{[(naphthalen-1-ylmethyl-carbamoyl]-methyl}-4-oxo-thiazolidin-3-yl-N-(3-morpholin-4-yl-propyl-acetamide, Interactions, Structural modification

  6. Acute inhibition of selected membrane-proximal mouse T cell receptor signaling by mitochondrial antagonists.

    Directory of Open Access Journals (Sweden)

    Kwangmi Kim

    2009-11-01

    Full Text Available T cells absorb nanometric membrane vesicles, prepared from plasma membrane of antigen presenting cells, via dual receptor/ligand interactions of T cell receptor (TCR with cognate peptide/major histocompatibility complex (MHC plus lymphocyte function-associated antigen 1 (LFA-1 with intercellular adhesion molecule 1. TCR-mediated signaling for LFA-1 activation is also required for the vesicle absorption. Exploiting those findings, we had established a high throughput screening (HTS platform and screened a library for isolation of small molecules inhibiting the vesicle absorption. Follow-up studies confirmed that treatments (1 hour with various mitochondrial antagonists, including a class of anti-diabetic drugs (i.e., Metformin and Phenformin, resulted in ubiquitous inhibition of the vesicle absorption without compromising viability of T cells. Further studies revealed that the mitochondrial drug treatments caused impairment of specific membrane-proximal TCR signaling event(s. Thus, activation of Akt and PLC-gamma1 and entry of extracellular Ca(2+ following TCR stimulation were attenuated while polymerization of monomeric actins upon TCR triggering progressed normally after the treatments. Dynamic F-actin rearrangement concurring with the vesicle absorption was also found to be impaired by the drug treatments, implying that the inhibition by the drug treatments of downstream signaling events (and the vesicle absorption could result from lack of directional relocation of signaling and cell surface molecules. We also assessed the potential application of mitochondrial antagonists as immune modulators by probing effects of the long-term drug treatments (24 hours on viability of resting primary T cells and cell cycle progression of antigen-stimulated T cells. This study unveils a novel regulatory mechanism for T cell immunity in response to environmental factors having effects on mitochondrial function.

  7. Human Interleukine-1 receptor antagonist:Cloning, Expression and Optimization in E.coli Host

    Directory of Open Access Journals (Sweden)

    Gh. Barati

    2014-07-01

    Full Text Available Introduction & Objective: Interleukine-1 receptor antagonist (IL-1RA is a powerful anti-inflammatory cytokine which limits the biological effects of IL-1. Due to structural similarity between IL-1 and its antagonist, IL-1RA competitively binds to IL-1 receptor which leads to no signal transduction. Therefore , it is applied in the treatment of patients with inflammatory diseases such as Rheumatoid Arthritis. The aim of this study is cloning, expression and op-timization of IL-1RA in E. coli. Materials & Methods: In this experimental study synthetically prepared cDNA was amplified by PCR. After double digestion with NdeI and XhoI restriction enzymes, this gene was cloned in pET28a expression vector. Expression of desired gene was analyzed at RNA level by RT-PCR and at protein level by SDS-PAGE and followed by western blot to confirm SDS-PAGE results. Optimization of recombinant protein expression was performed in dif-ferent IPTG concentrations and harvesting times after induction. Results: The presence of gene in pET28a was determined by colony-PCR and confirmed by restriction digestion. Transcription of cloned gene and expression of high yield recombinant protein were shown by RT-PCR and SDS-PAGE, respectively. The result of SDS-PAGE was confirmed by western blot. Expression was optimized in different induction time and IPTG concentrations Conclusion: The result of this study demonstrated expression of this recombinant protein at high level in E.coli system by pET28a expression vector. This study also showed a direct as-sociation between the increased level of expression and time of induction . Therefore, an overnight induction time with 0.1 mM IPTG concentration is recommended for a high level expression. (Sci J Hamadan Univ Med Sci 2014; 21 (2:145-151

  8. Combination of behaviorally sub-effective doses of glutamate NMDA and dopamine D1 receptor antagonists impairs executive function.

    Science.gov (United States)

    Desai, Sagar J; Allman, Brian L; Rajakumar, Nagalingam

    2017-04-14

    Impairment of executive function is a core feature of schizophrenia. Preclinical studies indicate that injections of either N-methyl d-aspartate (NMDA) or dopamine D 1 receptor blockers impair executive function. Despite the prevailing notion based on postmortem findings in schizophrenia that cortical areas have marked suppression of glutamate and dopamine, recent in vivo imaging studies suggest that abnormalities of these neurotransmitters in living patients may be quite subtle. Thus, we hypothesized that modest impairments in both glutamate and dopamine function can act synergistically to cause executive dysfunction. In the present study, we investigated the effect of combined administration of "behaviorally sub-effective" doses of NMDA and dopamine D 1 receptor antagonists on executive function. An operant conditioning-based set-shifting task was used to assess behavioral flexibility in rats that were systemically injected with NMDA and dopamine D 1 receptor antagonists individually or in combination prior to task performance. Separate injections of the NMDA receptor antagonist, MK-801, and the dopamine D 1 receptor antagonist, SCH 23390, at low doses did not impair set-shifting; however, the combined administration of these same behaviorally sub-effective doses of the antagonists significantly impaired the performance during set-shifting without affecting learning, retrieval of the memory of the initial rule, latency of responses or the number of omissions. The combined treatment also produced an increased number of perseverative errors. Our results indicate that NMDA and D 1 receptor blockade act synergistically to cause behavioral inflexibility, and as such, subtle abnormalities in glutamatergic and dopaminergic systems may act cooperatively to cause deficits in executive function. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Effect of α7 nicotinic acetylcholine receptor agonists and antagonists on motor function in mice

    International Nuclear Information System (INIS)

    Welch, Kevin D.; Pfister, James A.; Lima, Flavia G.; Green, Benedict T.; Gardner, Dale R.

    2013-01-01

    Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation channels found throughout the body, and serve to mediate diverse physiological functions. Muscle-type nAChRs located in the motor endplate region of muscle fibers play an integral role in muscle contraction and thus motor function. The toxicity and teratogenicity of many plants (which results in millions of dollars in losses annually to the livestock industry) are due to various toxins that bind to nAChRs including deltaline and methyllycaconitine (MLA) from larkspur (Delphinium) species, and nicotine and anabasine from tobacco (Nicotiana) species. The primary result of the actions of these alkaloids at nAChRs is neuromuscular paralysis and respiratory failure. The objective of this study was to further characterize the motor coordination deficiencies that occur upon exposure to a non-lethal dose of nAChR antagonists MLA and deltaline as well as nAChR agonists nicotine and anabasine. We evaluated the effect of nAChR agonists and antagonists on the motor function and coordination in mice using a balance beam, grip strength meter, rotarod, open field analysis and tremor monitor. These analyses demonstrated that within seconds after treatment the mice had significant loss of motor function and coordination that lasted up to 1 min, followed by a short period of quiescence. Recovery to normal muscle coordination was rapid, typically within approximately 10 min post-dosing. However, mice treated with the nAChR agonist nicotine and anabasine required a slightly longer time to recover some aspects of normal muscle function in comparison to mice treated with the nAChR antagonist MLA or deltaline. -- Highlights: ► Mice treated with nAChR agonists and antagonists have a loss in motor function. ► These deficits are temporary as near normal motor function returns within 10 min. ► There are compound-specific differences in the effects on motor function.

  10. 68Ga-DOTATOC PET/CT and somatostatin receptor (sst1-sst5) expression in normal human tissue: correlation of sst2 mRNA and SUVmax

    International Nuclear Information System (INIS)

    Boy, Christian; Poeppel, Thorsten D.; Jentzen, Walter; Brandau, Wolfgang; Bockisch, Andreas; Heusner, Till A.; Antoch, Gerald; Redmann-Bischofs, Anja; Unger, Nicole; Mann, Klaus; Petersenn, Stephan

    2011-01-01

    By targeting somatostatin receptors (sst) radiopeptides have been established for both diagnosis and therapy. For physiologically normal human tissues the study provides a normative database of maximum standardized uptake value (SUV max ) and sst mRNA. A total of 120 patients were subjected to diagnostic 68 Ga-DOTATOC positron emission tomography (PET)/CT (age range 19-83 years). SUV max values were measured in physiologically normal tissues defined by normal morphology, absence of surgical intervention and absence of metastatic spread during clinical follow-up. Expression of sst subtypes (sst1-sst5) was measured independently in pooled adult normal human tissue by real-time reverse transcriptase polymerase chain reaction (RT-PCR). SUV max revealed a region-specific pattern (e.g., mean ± SD, spleen 31.1 ± 10.9, kidney 16.9 ± 5.3, liver 12.8 ± 3.6, stomach 7.0 ± 3.1, head of pancreas 6.2 ± 2.3, small bowel 4.8 ± 1.8, thyroid 4.7 ± 2.2, bone 3.9 ± 1.3, large bowel 2.9 ± 0.8, muscle 2.1 ± 0.5, parotid gland 1.9 ± 0.6, axillary lymph node 0.8 ± 0.3 and lung 0.7 ± 0.3). SUV max was age independent. Gender differences were evident within the thyroid (female/male: 3.7 ± 1.6/5.5 ± 2.4, p max values exclusively correlated with sst2 expression (r = 0.846, p max with the expression of the other four subtypes. In normal human tissues 68 Ga-DOTATOC imaging has been related to the expression of sst2 at the level of mRNA. The novel normative database may improve diagnostics, monitoring and therapy of sst-expressing tumours or inflammation on a molecular basis. (orig.)

  11. Current knowledge on the sensitivity of the 68Ga-somatostatin receptor positron emission tomography and the SUVmax reference range for management of pancreatic neuroendocrine tumours

    International Nuclear Information System (INIS)

    Virgolini, Irene; Gabriel, Michael; Kroiss, Alexander; Guggenberg, Elisabeth von; Prommegger, Rupert; Warwitz, Boris; Nilica, Bernhard; Roig, Ilanos Geraldo; Rodrigues, Margarida; Uprimny, Christian

    2016-01-01

    Physiologically increased pancreatic uptake at the head/uncinate process is observed in more than one-third of patients after injection of one of the three 68 Ga-labelled octreotide-based peptides used for somatostatin (sst) receptor (r) imaging. There are minor differences between these 68 Ga-sstr-binding peptides in the imaging setting. On 68 Ga-sstr-imaging the physiological uptake can be diffuse or focal and usually remains stable over time. Differences in the maximal standardised uptake values (SUV max ) reported for the normal pancreas as well as for pancreatic neuroendocrine tumour (PNET) lesions may be related to several factors, including (a) differences in the peptide binding affinities as well as differences in sstr subtype expression of pancreatic α- and β-cells, and heterogeneity / density of tumour cells, (b) differences in scanner resolution, image reconstruction techniques and acquisition protocols, (c) mostly retrospective study designs, (d) mixed patient populations, or (e) interference with medications such as treatment with long-acting sst analogues. The major limitation in most of the studies lies in the lack of histopathological confirmation of abnormal findings. There is a significant overlap between the calculated SUV max -values for physiological pancreas and PNET-lesions of the head/uncinate process that do not favour the use of quantitative parameters in the clinical setting. Anecdotal long-term follow-up studies have even indicated that increased uptake in the head/uncinate process still can turn out to be malignant over years of follow up. SUV max -data for the pancreatic body and tail are limited. Therefore, any visible focal tracer uptake in the pancreas must be considered as suspicious for malignancy irrespective of quantitative parameters. In general, sstr-PET/CT has significant implications for the management of NET patients leading to a change in treatment decision in about one-third of patients. Therefore, follow-up with 68 Ga

  12. Current knowledge on the sensitivity of the (68)Ga-somatostatin receptor positron emission tomography and the SUVmax reference range for management of pancreatic neuroendocrine tumours.

    Science.gov (United States)

    Virgolini, Irene; Gabriel, Michael; Kroiss, Alexander; von Guggenberg, Elisabeth; Prommegger, Rupert; Warwitz, Boris; Nilica, Bernhard; Roig, Llanos Geraldo; Rodrigues, Margarida; Uprimny, Christian

    2016-10-01

    Physiologically increased pancreatic uptake at the head/uncinate process is observed in more than one-third of patients after injection of one of the three (68)Ga-labelled octreotide-based peptides used for somatostatin (sst) receptor (r) imaging. There are minor differences between these (68)Ga-sstr-binding peptides in the imaging setting. On (68)Ga-sstr-imaging the physiological uptake can be diffuse or focal and usually remains stable over time. Differences in the maximal standardised uptake values (SUVmax) reported for the normal pancreas as well as for pancreatic neuroendocrine tumour (PNET) lesions may be related to several factors, including (a) differences in the peptide binding affinities as well as differences in sstr subtype expression of pancreatic α- and β-cells, and heterogeneity / density of tumour cells, (b) differences in scanner resolution, image reconstruction techniques and acquisition protocols, (c) mostly retrospective study designs, (d) mixed patient populations, or (e) interference with medications such as treatment with long-acting sst analogues. The major limitation in most of the studies lies in the lack of histopathological confirmation of abnormal findings. There is a significant overlap between the calculated SUVmax-values for physiological pancreas and PNET-lesions of the head/uncinate process that do not favour the use of quantitative parameters in the clinical setting. Anecdotal long-term follow-up studies have even indicated that increased uptake in the head/uncinate process still can turn out to be malignant over years of follow up. SUVmax-data for the pancreatic body and tail are limited. Therefore, any visible focal tracer uptake in the pancreas must be considered as suspicious for malignancy irrespective of quantitative parameters. In general, sstr-PET/CT has significant implications for the management of NET patients leading to a change in treatment decision in about one-third of patients. Therefore, follow-up with (68)Ga

  13. Decision-tree model for health economic comparison of two long-acting somatostatin receptor ligand devices in France, Germany, and the UK.

    Science.gov (United States)

    Marty, Rémi; Roze, Stéphane; Kurth, Hannah

    2012-01-01

    Long-acting somatostatin receptor ligands (SRL) with product-specific formulation and means of administration are injected periodically in patients with acromegaly and neuroendocrine tumors. A simple decision-tree model aimed at comparing cost savings with ready-to-use Somatuline Autogel(®) (lanreotide) and Sandostatin LAR(®) (octreotide) for the UK, France, and Germany. The drivers of cost savings studied were the reduction of time to administer as well as a reduced baseline risk of clogging during product administration reported for Somatuline Autogel(®). The decision-tree model assumed two settings for SRL administration, ie, by either hospital-based or community-based nurses. In the case of clogging, the first dose was assumed to be lost and a second injection performed. Successful injection depended on the probability of clogging. Direct medical costs were included. A set of scenarios were run, varying the cost drivers, such as the baseline risk of clogging, SRL administration time, and percentage of patients injected during a hospital stay. Costs per successful injection were less for Somatuline Autogel(®)/Depot, ranging from Euros (EUR) 13-45, EUR 52-108, and EUR 127-151, respectively, for France, Germany, and the UK. The prices for both long-acting SRL were the same in France, and cost savings came to 100% from differences other than drug prices. For Germany and the UK, the proportion of savings due to less clogging and shorter administration time was estimated to be around 32% and 20%, respectively. Based on low and high country-specific patient cohort size estimations of individuals eligible for SRL treatment among the patient population with acromegaly and neuroendocrine tumors, annual savings were estimated to be up to EUR 2,000,000 for France, EUR 6,000,000 for Germany, and EUR 7,000,000 for the UK. This model suggests that increasing usage of the Somatuline device for injection of SRL might lead to substantial savings for health care providers

  14. Synthesis and properties of a new water-soluble prodrug of the adenosine A 2A receptor antagonist MSX-2.

    Science.gov (United States)

    Vollmann, Karl; Qurishi, Ramatullah; Hockemeyer, Jörg; Müller, Christa E

    2008-02-12

    The compound L-valine-3-{8-[(E)-2-[3-methoxyphenyl)ethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4) was synthesized as an amino acid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to be stable in artificial gastric acid, but readily cleaved by pig liver esterase.

  15. Effects of dopamine D1-like and D2-like antagonists on cocaine discrimination in muscarinic receptor knockout mice.

    Science.gov (United States)

    Thomsen, Morgane; Caine, Simon Barak

    2016-04-05

    Muscarinic and dopamine brain systems interact intimately, and muscarinic receptor ligands, like dopamine ligands, can modulate the reinforcing and discriminative stimulus (S(D)) effects of cocaine. To enlighten the dopamine/muscarinic interactions as they pertain to the S(D) effects of cocaine, we evaluated whether muscarinic M1, M2 or M4 receptors are necessary for dopamine D1 and/or D2 antagonist mediated modulation of the S(D) effects of cocaine. Knockout mice lacking M1, M2, or M4 receptors, as well as control wild-type mice and outbred Swiss-Webster mice, were trained to discriminate 10mg/kg cocaine from saline in a food-reinforced drug discrimination procedure. Effects of pretreatments with the dopamine D1 antagonist SCH 23390 and the dopamine D2 antagonist eticlopride were evaluated. In intact mice, both SCH 23390 and eticlopride attenuated the cocaine discriminative stimulus effect, as expected. SCH 23390 similarly attenuated the cocaine discriminative stimulus effect in M1 knockout mice, but not in mice lacking M2 or M4 receptors. The effects of eticlopride were comparable in each knockout strain. These findings demonstrate differences in the way that D1 and D2 antagonists modulate the S(D) effects of cocaine, D1 modulation being at least partially dependent upon activity at the inhibitory M2/M4 muscarinic subtypes, while D2 modulation appeared independent of these systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Effects of the CGRP receptor antagonist BIBN4096BS on capsaicin-induced carotid haemodynamic changes in anaesthetised pigs.

    NARCIS (Netherlands)

    K. Kapoor (Kapil); U. Arulmani (Udayasankar); J.P. Heiligers (Jan); I.M. Garrelds (Ingrid); E.W. Willems (Edwin); H. Doods (Henri); C.M. Villalón (Carlos); P.R. Saxena (Pramod Ranjan)

    2003-01-01

    textabstract1. Calcitonin gene-related peptide (CGRP), a potent vasodilator released from capsaicin-sensitive trigeminal sensory nerves, seems to be involved in the pathogenesis of migraine. Hence, CGRP receptor antagonists may serve as a novel treatment for migraine. This study

  17. Systematic review: Antacids, H2-receptor antagonists, prokinetics, bismuth and sucralfate therapy for non-ulcer dyspepsia.

    Science.gov (United States)

    Moayyedi, P; Soo, S; Deeks, J; Forman, D; Harris, A; Innes, M; Delaney, B

    2003-05-15

    Evidence for the effectiveness of antacids, histamine-2 receptor antagonists, bismuth salts, sucralfate and prokinetic therapy in non-ulcer dyspepsia is conflicting. To conduct a systematic review evaluating these therapies in non-ulcer dyspepsia. Electronic searches were performed using the Cochrane Controlled Trials Register, Medline, EMBASE, Cinahl and SIGLE until September 2002. Dyspepsia outcomes were dichotomized into cured/improved vs. same/worse. Prokinetics [14 trials, 1053 patients; relative risk reduction (RRR), 48%; 95% confidence interval (95% CI), 27-63%] and histamine-2 receptor antagonists (11 trials, 2164 patients; RRR, 22%; 95% CI, 7-35%) were significantly more effective than placebo. Bismuth salts (RRR, 40%; 95% CI, - 3% to 65%) were superior to placebo, but this was of marginal statistical significance. Antacids and sucralfate were not statistically significantly superior to placebo. A funnel plot suggested that the prokinetic and histamine-2 receptor antagonist results could be due to publication bias. The meta-analyses suggest that histamine-2 receptor antagonists and prokinetics are superior to placebo. These data are difficult to interpret, however, as funnel plot asymmetry suggests that the magnitude of the effect could be due to publication bias or other heterogeneity-related issues.

  18. The N-Methyl d-Aspartate Glutamate Receptor Antagonist Ketamine Disrupts the Functional State of the Corticothalamic Pathway

    NARCIS (Netherlands)

    Anderson, P.M.; Jones, N.C.; O'Brien, T.J.; Pinault, D.

    2017-01-01

    The non-competitive N-methyl d-aspartate glutamate receptor (NMDAR) antagonist ketamine elicits a brain state resembling high-risk states for developing psychosis and early stages of schizophrenia characterized by sensory and cognitive deficits and aberrant ongoing gamma (30-80 Hz) oscillations in

  19. Synthesis and Properties of a New Water-Soluble Prodrug of the Adenosine A2A Receptor Antagonist MSX-2

    Directory of Open Access Journals (Sweden)

    Christa E. Müller

    2008-02-01

    Full Text Available The compound L-valine-3-{8-[(E-2-[3-methoxyphenylethenyl]-7-methyl-1-propargylxanthine-3-yl}propyl ester hydrochloride (MSX-4 was synthesized as an aminoacid ester prodrug of the adenosine A2A receptor antagonist MSX-2. It was found to bestable in artificial gastric acid, but readily cleaved by pig liver esterase.

  20. ANG II type 1 receptor antagonist irbesartan inhibits coronary angiogenesis stimulated by chronic intermittent hypoxia in neonatal rats

    Czech Academy of Sciences Publication Activity Database

    Rakusan, K.; Chvojková, Zuzana; Oliviero, P.; Ošťádalová, Ivana; Kolář, František; Chassagne, C.; Samuel, J. L.; Ošťádal, Bohuslav

    2007-01-01

    Roč. 292, č. 3 (2007), H1237-H1244 ISSN 0363-6135 R&D Projects: GA MŠk 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : angiogenesis neonatal rat * ANG II type 1 receptor antagonist heart * ischemic tolerance Subject RIV: ED - Physiology Impact factor: 3.973, year: 2007

  1. Cannabinoid CB1 receptor antagonist rimonabant disrupts nicotine reward-associated memory in rats.

    Science.gov (United States)

    Fang, Qin; Li, Fang-Qiong; Li, Yan-Qin; Xue, Yan-Xue; He, Ying-Ying; Liu, Jian-Feng; Lu, Lin; Wang, Ji-Shi

    2011-10-01

    Exposure to cues previously associated with drug intake leads to relapse by activating previously acquired memories. Based on previous findings, in which cannabinoid CB(1) receptors were found to be critically involved in specific aspects of learning and memory, we investigated the role of CB(1) receptors in nicotine reward memory using a rat conditioned place preference (CPP) model. In Experiment 1, rats were trained for CPP with alternating injections of nicotine (0.5mg/kg, s.c.) and saline to acquire the nicotine-conditioned memory. To examine the effects of rimonabant on the reconsolidation of nicotine reward memory, rats were administered rimonabant (0, 0.3, and 3.0mg/kg, i.p.) immediately after reexposure to the drug-paired context. In Experiment 2, rats were trained for CPP similarly to Experiment 1. To examine the effects of rimonabant on the reinstatement of nicotine reward memory, rimonabant (0, 0.3, and 3.0mg/kg, i.p.) was administered before the test of nicotine-induced CPP reinstatement. In Experiment 3, to evaluate whether rimonabant itself produces a reward memory, rats were trained for CPP with alternating injections of different doses of rimonabant (0, 0.3, and 3.0mg/kg) and saline. Rimonabant at a dose of 3.0mg/kg significantly disrupted the reconsolidation of nicotine memory and significantly blocked the reinstatement of nicotine-induced CPP. However, rimonabant itself did not produce CPP. These findings provide clear evidence that CB(1) receptors play a role in nicotine reward memory, suggesting that CB(1) receptor antagonists may be a potential target for managing nicotine addiction. Copyright © 2011 Elsevier Inc. All rights reserved.

  2. Reversal of sibutramine-induced anorexia with a selective 5-HT(2C) receptor antagonist.

    Science.gov (United States)

    Higgs, Suzanne; Cooper, Alison J; Barnes, Nicholas M

    2011-04-01

    The monoamine reuptake inhibitor sibutramine reduces food intake but the receptor subtypes mediating the effects of sibutramine on feeding remain to be clearly identified. The involvement of the 5-HT(2C) receptor subtype in the satiety-enhancing effects of sibutramine was investigated by examining the effects of co-administration of sibutramine with the selective 5-HT(2C) receptor antagonist SB 242084 Microstructural analyses of licking for a glucose solution by non-deprived, male rats were performed over a range of doses of sibutramine to identify a selective satiety-enhancing dose (experiment 1). Similar analyses were performed after administration of a vehicle control, two doses of SB 242084 alone or two doses of SB 242084 in combination with sibutramine (experiment 2). Sibutramine at doses of 1-3 mg/kg selectively reduced glucose consumption via a reduction in the number of bouts of licking. Non-selective effects to increase latency to lick were only observed at the higher dose of 6 mg/kg. Co-administration of sibutramine (3 mg/kg) with SB 242084 (1 or 3 mg/kg) reversed the effect of sibutramine on bout number whereas either dose of SB 242084 alone had no significant effect. We confirm behaviourally selective effects of sibutramine on feeding and provide further support for the satiety-enhancing effects of sibutramine. Our data also provide evidence for the involvement of the 5-HT(2C) receptor in the satiety-enhancing effects of sibutramine although additional targets may have an impact, and further investigation of the molecular mechanisms underlying the efficacy of sibutramine as an anorectic is warranted.

  3. Dual orexin receptor antagonists - promising agents in the treatment of sleep disorders.

    Science.gov (United States)

    Pałasz, Artur; Lapray, Damien; Peyron, Christelle; Rojczyk-Gołębiewska, Ewa; Skowronek, Rafał; Markowski, Grzegorz; Czajkowska, Beata; Krzystanek, Marek; Wiaderkiewicz, Ryszard

    2014-01-01

    Insomnia is a serious medical and social problem, its prevalence in the general population ranges from 9 to 35% depending on the country and assessment method. Often, patients are subject to inappropriate and therefore dangerous pharmacotherapies that include prolonged administration of hypnotic drugs, benzodiazepines and other GABAA receptor modulators. This usually does not lead to a satisfactory improvement in patients' clinical states and may cause lifelong drug dependence. Brain state transitions require the coordinated activity of numerous neuronal pathways and brain structures. It is thought that orexin-expressing neurons play a crucial role in this process. Due to their interaction with the sleep-wake-regulating neuronal population, they can activate vigilance-promoting regions and prevent unwanted sleep intrusions. Understanding the multiple orexin modulatory effects is crucial in the context of pathogenesis of insomnia and should lead to the development of novel treatments. An important step in this process was the synthesis of dual antagonists of orexin receptors. Crucially, these drugs, as opposed to benzodiazepines, do not change the sleep architecture and have limited side-effects. This new pharmacological approach might be the most appropriate to treat insomnia.

  4. Pharmacokinetic/Pharmacodynamic Modelling of Receptor Internalization with CRTH2 Antagonists to Optimize Dose Selection.

    Science.gov (United States)

    Krause, Andreas; Zisowsky, Jochen; Strasser, Daniel S; Gehin, Martine; Sidharta, Patricia N; Groenen, Peter M A; Dingemanse, Jasper

    2016-07-01

    The chemoattractant receptor-homologous molecule expressed on T helper-2 cells (CRTH2) is a G-protein-coupled receptor for prostaglandin D2 (PGD2), a key mediator in inflammatory disorders. Two selective and potent CRTH2 antagonists currently in clinical development, ACT-453859 and setipiprant, were compared with respect to their (predicted) clinical efficacy. Population pharmacokinetic (PK) and pharmacodynamic (PD) models were developed to characterize how plasma concentrations (PK) of ACT-453859, its active metabolite ACT-463036 and setipiprant related to their effect on blocking PGD2-induced internalization of CRTH2 on eosinophils (PD). Simulations were used to identify doses and dosing regimens leading to 90 % of maximum blockade of CRTH2 internalization at trough. A combined concentration of ACT-453859 and its metabolite ACT-463036, with weights proportional to potency (based on an eosinophil shape change assay), enabled good characterization of the PD effect. The modelling and simulation results facilitated decision making by suggesting an ACT-453859 dose of 400 mg once daily (or 100 mg twice daily) for clinically relevant CRTH2 antagonism. Pharmacometric quantification demonstrated that CRTH2 internalization is a useful new biomarker to study CRTH2 antagonism. Ninety percent of maximum blockade of CRTH2 internalization at trough is suggested as a quantitative PD target in clinical studies.

  5. Synthesis and Evaluation of Orexin-1 Receptor Antagonists with Improved Solubility and CNS Permeability.

    Science.gov (United States)

    Perrey, David A; Decker, Ann M; Zhang, Yanan

    2018-03-21

    Orexins are hypothalamic neuropeptides playing important roles in many functions including the motivation of addictive behaviors. Blockade of the orexin-1 receptor has been suggested as a potential strategy for the treatment of drug addiction. We have previously reported OX 1 receptor antagonists based on the tetrahydroisoquinoline scaffold with excellent OX 1 potency and selectivity; however, these compounds had high lipophilicity (clogP > 5) and low to moderate solubility. In an effort to improve their properties, we have designed and synthesized a series of analogues where the 7-position substituents known to favor OX 1 potency and selectivity were retained, and groups of different nature were introduced at the 1-position where substitution was generally tolerated as demonstrated in previous studies. Compound 44 with lower lipophilicity (clogP = 3.07) displayed excellent OX 1 potency ( K e = 5.7 nM) and selectivity (>1,760-fold over OX 2 ) in calcium mobilization assays. In preliminary ADME studies, 44 showed excellent kinetic solubility (>200 μM), good CNS permeability ( P app = 14.7 × 10 -6 cm/sec in MDCK assay), and low drug efflux (efflux ratio = 3.3).

  6. JB-9322, a new selective histamine H2-receptor antagonist with potent gastric mucosal protective properties.

    Science.gov (United States)

    Palacios, B; Montero, M J; Sevilla, M A; Román, L S

    1995-05-01

    1. JB-9322 is a selective histamine H2-receptor antagonist with gastric antisecretory activity and mucosal protective properties. 2. The affinity of JB-9322 for the guinea-pig atria histamine H2-receptor was approximately 2 times greater than that of ranitidine. 3. In vivo, the ID50 value for the inhibition of gastric acid secretion in pylorus-ligated rats was 5.28 mg kg-1 intraperitoneally. JB-9322 also dose-dependently inhibited gastric juice volume and pepsin secretion. In gastric lumen-perfused rats, intravenous injection of JB-9322 dose-dependently reduced histamine-, pentagastrin- and carbachol-stimulated gastric acid secretion. 4. JB-9322 showed antiulcer activity against aspirin and indomethacin-induced gastric lesions and was more potent than ranitidine. 5. JB-9322 effectively inhibited macroscopic gastric haemorrhagic lesions induced by ethanol. Intraperitoneal injection was effective in preventing the lesions as well as oral treatment. The oral ID50 value for these lesions was 1.33 mg kg-1. By contrast, ranitidine (50 mg kg-1) failed to reduce these lesions. In addition, the protective effect of JB-9322 was independent of prostaglandin synthesis. 6. These results indicate that JB-9322 is a new antiulcer drug that exerts a potent cytoprotective effect in addition to its gastric antisecretory activity.

  7. Task-specific enhancement of short-term, but not long-term, memory by class I metabotropic glutamate receptor antagonist 1-aminoindan-1,5-dicarboxylic acid in rats

    DEFF Research Database (Denmark)

    Christoffersen, G.R.J.; Christensen, Lone H.; Harrington, Nicholas R.

    1999-01-01

    Metabotropic glutamate receptors; Class I antagonist; 1-aminoindan-1,5-dicarboxylic acid; spatial learning; contextual conditioning; rats......Metabotropic glutamate receptors; Class I antagonist; 1-aminoindan-1,5-dicarboxylic acid; spatial learning; contextual conditioning; rats...

  8. S961, an insulin receptor antagonist causes hyperinsulinemia, insulin-resistance and depletion of energy stores in rats

    Energy Technology Data Exchange (ETDEWEB)

    Vikram, Ajit [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Mohali, Punjab 160 062 (India); Jena, Gopabandhu, E-mail: gbjena@gmail.com [Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Mohali, Punjab 160 062 (India)

    2010-07-23

    Research highlights: {yields}Insulin receptor antagonist S961 causes hyperglycemia, hyperinsulinemia and insulin resistance in rats. {yields}Peroxysome-proliferator-activated-receptor-gamma agonist pioglitazone improves S961 induced hyperglycemia and glucose intolerance. {yields}Long term treatment with insulin receptor antagonist S961 results in the decreased adiposity and hepatic glycogen content. {yields}Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. -- Abstract: Impairment in the insulin receptor signaling and insulin mediated effects are the key features of type 2 diabetes. Here we report that S961, a peptide insulin receptor antagonist induces hyperglycemia, hyperinsulinemia ({approx}18-fold), glucose intolerance and impairment in the insulin mediated glucose disposal in the Sprague-Dawley rats. Further, long-term S961 treatment (15 day, 10 nM/kg/day) depletes energy storage as evident from decrease in the adiposity and hepatic glycogen content. However, peroxysome-proliferator-activated-receptor-gamma (PPAR{gamma}) agonist pioglitazone significantly (P < 0.001) restored S961 induced hyperglycemia (196.73 {+-} 16.32 vs. 126.37 {+-} 27.07 mg/dl) and glucose intolerance ({approx}78%). Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. Further, results of the present study reconfirms and provide direct evidence to the crucial role of insulin receptor signaling in the glucose homeostasis and fuel metabolism.

  9. S961, an insulin receptor antagonist causes hyperinsulinemia, insulin-resistance and depletion of energy stores in rats

    International Nuclear Information System (INIS)

    Vikram, Ajit; Jena, Gopabandhu

    2010-01-01

    Research highlights: →Insulin receptor antagonist S961 causes hyperglycemia, hyperinsulinemia and insulin resistance in rats. →Peroxysome-proliferator-activated-receptor-gamma agonist pioglitazone improves S961 induced hyperglycemia and glucose intolerance. →Long term treatment with insulin receptor antagonist S961 results in the decreased adiposity and hepatic glycogen content. →Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. -- Abstract: Impairment in the insulin receptor signaling and insulin mediated effects are the key features of type 2 diabetes. Here we report that S961, a peptide insulin receptor antagonist induces hyperglycemia, hyperinsulinemia (∼18-fold), glucose intolerance and impairment in the insulin mediated glucose disposal in the Sprague-Dawley rats. Further, long-term S961 treatment (15 day, 10 nM/kg/day) depletes energy storage as evident from decrease in the adiposity and hepatic glycogen content. However, peroxysome-proliferator-activated-receptor-gamma (PPARγ) agonist pioglitazone significantly (P < 0.001) restored S961 induced hyperglycemia (196.73 ± 16.32 vs. 126.37 ± 27.07 mg/dl) and glucose intolerance (∼78%). Improvement in the hyperglycemia and glucose intolerance by pioglitazone clearly demonstrates that S961 treated rats can be successfully used to screen the novel therapeutic interventions having potential to improve glucose disposal through receptor independent mechanisms. Further, results of the present study reconfirms and provide direct evidence to the crucial role of insulin receptor signaling in the glucose homeostasis and fuel metabolism.

  10. Differential effects of m1 and m2 receptor antagonists in perirhinal cortex on visual recognition memory in monkeys.

    Science.gov (United States)

    Wu, Wei; Saunders, Richard C; Mishkin, Mortimer; Turchi, Janita

    2012-07-01

    Microinfusions of the nonselective muscarinic antagonist scopolamine into perirhinal cortex impairs performance on visual recognition tasks, indicating that muscarinic receptors in this region play a pivotal role in recognition memory. To assess the mnemonic effects of selective blockade in perirhinal cortex of muscarinic receptor subtypes, we locally infused either the m1-selective antagonist pirenzepine or the m2-selective antagonist methoctramine in animals performing one-trial visual recognition, and compared these scores with those following infusions of equivalent volumes of saline. Compared to these control infusions, injections of pirenzepine, but not of methoctramine, significantly impaired recognition accuracy. Further, similar doses of scopolamine and pirenzepine yielded similar deficits, suggesting that the deficits obtained earlier with scopolamine were due mainly, if not exclusively, to blockade of m1 receptors. The present findings indicate that m1 and m2 receptors have functionally dissociable roles, and that the formation of new visual memories is critically dependent on the cholinergic activation of m1 receptors located on perirhinal cells. Published by Elsevier Inc.

  11. Structure of the Human Dopamine D3 Receptor in Complex with a D2/D3 Selective Antagonist

    Energy Technology Data Exchange (ETDEWEB)

    Chien, Ellen Y.T.; Liu, Wei; Zhao, Qiang; Katritch, Vsevolod; Han, Gye Won; Hanson, Michael A.; Shi, Lei; Newman, Amy Hauck; Javitch, Jonathan A.; Cherezov, Vadim; Stevens, Raymond C. (Cornell); (Scripps); (NIDA); (Columbia); (UCSD); (Receptos)

    2010-11-30

    Dopamine modulates movement, cognition, and emotion through activation of dopamine G protein-coupled receptors in the brain. The crystal structure of the human dopamine D3 receptor (D3R) in complex with the small molecule D2R/D3R-specific antagonist eticlopride reveals important features of the ligand binding pocket and extracellular loops. On the intracellular side of the receptor, a locked conformation of the ionic lock and two distinctly different conformations of intracellular loop 2 are observed. Docking of R-22, a D3R-selective antagonist, reveals an extracellular extension of the eticlopride binding site that comprises a second binding pocket for the aryl amide of R-22, which differs between the highly homologous D2R and D3R. This difference provides direction to the design of D3R-selective agents for treating drug abuse and other neuropsychiatric indications.

  12. The CB1 receptor antagonist AM251 impairs reconsolidation of pavlovian fear memory in the rat basolateral amygdala.

    Science.gov (United States)

    Ratano, Patrizia; Everitt, Barry J; Milton, Amy L

    2014-10-01

    We have investigated the requirement for signaling at CB1 receptors in the reconsolidation of a previously consolidated auditory fear memory, by infusing the CB1 receptor antagonist AM251, or the FAAH inhibitor URB597, directly into the basolateral amygdala (BLA) in conjunction with memory reactivation. AM251 disrupted memory restabilization, but only when administered after reactivation. URB597 produced a small, transient enhancement of memory restabilization when administered after reactivation. The amnestic effect of AM251 was rescued by coadministration of the GABAA receptor antagonist bicuculline at reactivation, indicating that the disruption of reconsolidation was mediated by altered GABAergic transmission in the BLA. These data show that the endocannabinoid system in the BLA is an important modulator of fear memory reconsolidation and that its effects on memory are mediated by an interaction with the GABAergic system. Thus, targeting the endocannabinoid system may have therapeutic potential to reduce the impact of maladaptive memories in neuropsychiatric disorders such as posttraumatic stress disorder.

  13. Exploring the binding energy profiles of full agonists, partial agonists, and antagonists of the α7 nicotinic acetylcholine receptor.

    Science.gov (United States)

    Tabassum, Nargis; Ma, Qianyun; Wu, Guanzhao; Jiang, Tao; Yu, Rilei

    2017-09-01

    Nicotinic acetylcholine receptors (nAChRs) belong to the Cys-loop receptor family and are important drug targets for the treatment of neurological diseases. However, the precise determinants of the binding efficacies of ligands for these receptors are unclear. Therefore, in this study, the binding energy profiles of various ligands (full agonists, partial agonists, and antagonists) were quantified by docking those ligands with structural ensembles of the α7 nAChR exhibiting different degrees of C-loop closure. This approximate treatment of interactions suggested that full agonists, partial agonists, and antagonists of the α7 nAChR possess distinctive binding energy profiles. Results from docking revealed that ligand binding efficacy may be related to the capacity of the ligand to stabilize conformational states with a closed C loop.

  14. THE CANNABINOID RECEPTOR ANTAGONIST AM251 INCREASES PARAOXON AND CHLORPYRIFOS OXON TOXICITY IN RATS

    Science.gov (United States)

    Liu, Jing; Pope, Carey

    2014-01-01

    Organophosphorus anticholinesterases (OPs) elicit acute toxicity by inhibiting acetylcholinesterase (AChE), leading to acetylcholine accumulation and overstimulation of cholinergic receptors. Endocannabinoids (eCBs, e.g., arachidonoyl ethanolamide [AEA] and 2-arachidonoyl glycerol [2-AG]) are neuromodulators that regulate neurotransmission by reducing neurotransmitter release. The eCBs are degraded by the enzymes fatty acid amide hydrolase (FAAH, primarily involved in hydrolysis of AEA) and monoacylglycerol lipase (MAGL, primarily responsible for metabolism of 2-AG). We previously reported that the cannabinoid receptor agonist WIN 55,212-2 reduced cholinergic toxicity after paraoxon exposure. This study compared the effects of the cannabinoid receptor antagonist AM251 on acute toxicity following either paraoxon (PO) or chlorpyrifos oxon (CPO). CPO was more potent in vitro than PO at inhibiting AChE (≈ 2 fold), FAAH (≈ 8 fold), and MAGL (≈ 19 fold). Rats were treated with vehicle, PO (0.3 and 0.6 mg/kg, sc.) or CPO (6 and 12 mg/kg, sc.) and subsets treated with AM251 (3 mg/kg, ip; 30 min after OP). Signs of toxicity were recorded for four hours and rats were then sacrificed. OP-treated rats showed dose-related involuntary movements, with AM251 increasing signs of toxicity with the lower dosages. PO and CPO elicited excessive secretions, but AM251 had no apparent effect with either OP. Lethality was increased by AM251 with the higher dosage of PO, but no lethality was noted with either dosage of CPO, with or without AM251. Both OPs caused extensive inhibition of hippocampal AChE and FAAH (>80–90%), but only CPO inhibited MAGL (37–50%). These results provide further evidence that eCB signaling can influence acute OP toxicity. The selective in vivo inhibition of MAGL by CPO may be important in the differential lethality noted between PO and CPO with AM251 co-administration. PMID:25447325

  15. Attenuation of saccharin-seeking in rats by orexin/hypocretin receptor 1 antagonist.

    Science.gov (United States)

    Cason, Angie M; Aston-Jones, Gary

    2013-08-01

    The orexin (Orx)/hypocretin system has been implicated in reward-seeking, especially for highly salient food and drug rewards. We recently demonstrated that signaling at the OxR1 receptor is involved in sucrose reinforcement and reinstatement of sucrose-seeking elicited by sucrose-paired cues in food-restricted rats. Because sucrose reinforcement has both a hedonic and caloric component, it remains unknown what aspect of this reward drives its reinforcing value. The present study examined the involvement of the Orx system in operant responding for saccharin, a noncaloric, hedonic (sweet) reward, and in cue-induced reinstatement of extinguished saccharin-seeking in ad libitum-fed vs food-restricted male subjects. Male Sprague Dawley rats were fed ad libitum or food-restricted and trained to self-administer saccharin. We determined the effects of pretreatment with the OxR1 receptor antagonist SB-334867 (SB; 10-30 mg/kg) on fixed ratio (FR) saccharin self-administration and on cue-induced reinstatement of extinguished saccharin-seeking. SB decreased responding and number of reinforcers earned during FR responding for saccharin and decreased cue-induced reinstatement of extinguished saccharin-seeking. All of these effects were obtained similarly in food-restricted and ad libitum-fed rats. These results indicate that signaling at the OxR1 receptor is involved in saccharin reinforcement and reinstatement of saccharin-seeking elicited by saccharin-paired cues regardless of food restriction. These findings lead us to conclude that the Orx system contributes to the motivational effects of hedonic food rewards, independently of caloric value and homeostatic needs.

  16. Somatostatin receptor PET in neuroendocrine tumours: 68Ga-DOTA0,Tyr3-octreotide versus 68Ga-DOTA0-lanreotide.

    Science.gov (United States)

    Putzer, Daniel; Kroiss, Alexander; Waitz, Dietmar; Gabriel, Michael; Traub-Weidinger, Tatjana; Uprimny, Christian; von Guggenberg, Elisabeth; Decristoforo, Clemens; Warwitz, Boris; Widmann, Gerlig; Virgolini, Irene Johanna

    2013-02-01

    The aim of this study was to evaluate the impact of (68)Ga-labelled DOTA(0)-lanreotide ((68)Ga-DOTA-LAN) on the diagnostic assessment of neuroendocrine tumour (NET) patients with low to moderate uptake on planar somatostatin receptor (SSTR) scintigraphy or (68)Ga-labelled DOTA(0),Tyr(3)-octreotide ((68)Ga-DOTA-TOC) positron emission tomography (PET). Fifty-three patients with histologically confirmed NET and clinical signs of progressive disease, who had not qualified for peptide receptor radionuclide therapy (PRRT) on planar SSTR scintigraphy or (68)Ga-DOTA-TOC PET (n = 38) due to lack of tracer uptake, underwent (68)Ga-DOTA-LAN PET to evaluate a treatment option with (90)Y-labelled lanreotide according to the MAURITIUS trial. The included patients received 150 ± 30 MBq of each radiopharmaceutical intravenously. PET scans were acquired 60-90 min after intravenous bolus injection. Image results from both PET scans were compared head to head, focusing on the intensity of tracer uptake in terms of treatment decision. CT was used for morphologic correlation of tumour lesions. To further evaluate the binding affinities of each tracer, quantitative and qualitative values were calculated for target lesions. (68)Ga-DOTA-LAN and (68)Ga-DOTA-TOC both showed equivalent findings in 24/38 patients when fused PET/CT images were interpreted. The sensitivity, specificity and accuracy of (68)Ga-DOTA-LAN in comparison to CT were 0.63, 0.5 and 0.62 (n = 53; p < 0.0001) and for (68)Ga-DOTA-TOC in comparison to CT 0.78, 0.5 and 0.76 (n = 38; p < 0.013), respectively. (68)Ga-DOTA-TOC showed a significantly higher maximum standardized uptake value (SUV(max)) regarding the primary tumour in 25 patients (p < 0.003) and regarding the liver in 30 patients (p < 0.009) compared to (68)Ga-DOTA-LAN. Corresponding values of both PET scans for tumour and liver did not show any significant correlation. (68)Ga-DOTA-TOC revealed more tumour sites than (68)Ga

  17. Somatostatin receptor PET in neuroendocrine tumours: {sup 68}Ga-DOTA{sup 0},Tyr{sup 3}-octreotide versus {sup 68}Ga-DOTA{sup 0}-lanreotide

    Energy Technology Data Exchange (ETDEWEB)

    Putzer, Daniel; Kroiss, Alexander; Waitz, Dietmar; Gabriel, Michael; Uprimny, Christian; Guggenberg, Elisabeth von; Decristoforo, Clemens; Warwitz, Boris; Virgolini, Irene Johanna [Innsbruck Medical University, Department of Nuclear Medicine, Innsbruck (Austria); Traub-Weidinger, Tatjana [Vienna Medical University, Department of Nuclear Medicine, Vienna (Austria); Widmann, Gerlig [Innsbruck Medical University, Department of Radiology, Innsbruck (Austria)

    2013-03-15

    The aim of this study was to evaluate