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Sample records for prolactin receptor antagonists

  1. 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....

  2. Different serotonin receptor types participate in 5-hydroxytryptophan-induced gonadotropins and prolactin release in the female infantile rat.

    Science.gov (United States)

    Lacau-Mengido, I M; Libertun, C; Becú-Villalobos, D

    1996-05-01

    Serotonin (5-HT) receptors can be classified into at least three, possibly up to seven, classes of receptors. They comprise the 5-HT1, 5-HT2, and 5-HT3 classes, the "uncloned' 5-HT4 receptor and the recombinant receptors 5-ht5, 5-ht6 and 5-ht7. We investigated the role of different serotonin receptor types in a neuroendocrine response to the activation of the serotonergic system. Female immature rats were chosen as an experimental model as it has been shown that during the 3rd week of life, and not at later developmental stages, 5-hydroxytryptophan (5-HTP, a serotonin precursor) induces gonadotropin release in females and not in males. Besides, at this age, serotonin releases prolactin in both sexes. 5-HTP (50 mg/kg) released prolactin, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) as expected. Ketanserin (5-HT2A antagonist) and methysergide (5-HT2C antagonist) blocked 5-HTP-induced prolactin release, but did not block the LH or FSH responses. Ondansetron (5-HT3 receptor antagonist) did not modify prolactin response to 5-HTP, whereas it blocked 5-HTP-induced LH and FSH release. Propranolol (5-HT1 and beta-adrenergic antagonist) blocked prolactin, LH and FSH release induced by 5-HTP. The 5-HT2C agonist 1-(3-chlorophenyl)piperazine dihydrochloride released prolactin, without modifying LH or FSH release. Methyl-quipazine and phenylbiguanide (5-HT3 agonists) increased both LH and FSH levels, without altering prolactin secretion. The present experiments indicate that serotonin acting at the 5-HT3 receptor mediates LH and FSH release in infantile female rats, whereas 5-HT2C or 2A receptor types participate in the release of prolactin at this age. 5-HT1 receptor type may be involved in the release of the three hormones, though a beta-adrenergic component of the response cannot be discarded.

  3. Effects of LHRH and ANG II on prolactin stimulation are mediated by hypophysial AT1 receptor subtype.

    Science.gov (United States)

    Becú-Villalobos, D; Lacau-Mengido, I M; Thyssen, S M; Díaz-Torga, G S; Libertun, C

    1994-02-01

    We have used the nonpeptide angiotensin II (ANG II) receptor antagonists losartan (receptor subtype AT1) and PD-123319 (AT2) to determine the participation of ANG II receptor subtypes in luteinizing hormone-releasing hormone (LHRH)-induced prolactin release in a perifusion study using intact pituitaries in vitro. LHRH (1.85 x 10(-7) M) released prolactin consistently, whereas losartan (10(-5) M) abolished prolactin response without modifying basal prolactin or luteinizing hormone (LH) and follicle-stimulating hormone (FSH) release. PD-123319 (10(-5) M) had no effect on basal or LHRH-induced prolactin, LH, or FSH release. We also determined that the effect of ANG II on prolactin release was mediated by the same receptor subtype. In adenohypophysial cells dispersed in vitro ANG II (10(-8) M) released prolactin. Losartan (10(-7) and 10(-6) M), but not PD-123319, inhibited this effect. We conclude that in intact hypophyses of 15-day-old female rats the effect of LHRH on prolactin release is readily demonstrated. LHRH-induced prolactin release appears to be mediated by ANG II acting in a paracrine manner on AT1 receptors located on lactotrophs.

  4. Maintenance of prolactin receptors in human breast cancer

    International Nuclear Information System (INIS)

    Ben-David, M.; Dror, Y.; Biran, S.

    1981-01-01

    Breast tissue specimens of 110 women with various stages of breast cancer were tested in vitro to determine their specific binding sites for human prolactin. In contrast to the case of steroid receptors, binding sites for prolactin were found in the vast majority of breast cancer tissue. Distribution profiles giving amount of prolactin receptor and their affinity coefficients were found to be similar in the tissues of women whose ages, hormonal status, or stage of breast cancer varied. These findings show that in contrast to steroid receptors, human breast cancer tissue maintains binding sites for prolactin. The findings also indicate that there may be a higher dependency of breast cancer on prolactin than on steroids. Clinical trials must be carried out to determine the role of ''positive'' prolactin receptors in prognosis and prediction of response to future hormone therapy. (author)

  5. Prolactin-sensitive neurons express estrogen receptor-α and depend on sex hormones for normal responsiveness to prolactin.

    Science.gov (United States)

    Furigo, Isadora C; Kim, Ki Woo; Nagaishi, Vanessa S; Ramos-Lobo, Angela M; de Alencar, Amanda; Pedroso, João A B; Metzger, Martin; Donato, Jose

    2014-05-30

    Estrogens and prolactin share important target tissues, including the gonads, brain, liver, kidneys and some types of cancer cells. Herein, we sought anatomical and functional evidence of possible crosstalk between prolactin and estrogens in the mouse brain. First, we determined the distribution of prolactin-responsive neurons that express the estrogen receptor α (ERα). A large number of prolactin-induced pSTAT5-immunoreactive neurons expressing ERα mRNA were observed in several brain areas, including the anteroventral periventricular nucleus, medial preoptic nucleus, arcuate nucleus of the hypothalamus, ventrolateral subdivision of the ventromedial nucleus of the hypothalamus (VMH), medial nucleus of the amygdala and nucleus of the solitary tract. However, although the medial preoptic area, periventricular nucleus of the hypothalamus, paraventricular nucleus of the hypothalamus, retrochiasmatic area, dorsomedial subdivision of the VMH, lateral hypothalamic area, dorsomedial nucleus of the hypothalamus and ventral premammillary nucleus contained significant numbers of prolactin-responsive neurons, these areas showed very few pSTAT5-immunoreactive cells expressing ERα mRNA. Second, we evaluated prolactin sensitivity in ovariectomized mice and observed that sex hormones are required for a normal responsiveness to prolactin as ovariectomized mice showed a lower number of prolactin-induced pSTAT5 immunoreactive neurons in all analyzed brain nuclei compared to gonad-intact females. In addition, we performed hypothalamic gene expression analyses to determine possible post-ovariectomy changes in components of prolactin signaling. We observed no significant changes in the mRNA expression of prolactin receptor, STAT5a or STAT5b. In summary, sex hormones exert a permissive role in maintaining the brain's prolactin sensitivity, most likely through post-transcriptional mechanisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  6. Regulatory role of melatonin and BMP-4 in prolactin production by rat pituitary lactotrope GH3 cells.

    Science.gov (United States)

    Ogura-Ochi, Kanako; Fujisawa, Satoshi; Iwata, Nahoko; Komatsubara, Motoshi; Nishiyama, Yuki; Tsukamoto-Yamauchi, Naoko; Inagaki, Kenichi; Wada, Jun; Otsuka, Fumio

    2017-08-01

    The effects of melatonin on prolactin production and its regulatory mechanism remain uncertain. We investigated the regulatory role of melatonin in prolactin production using rat pituitary lactotrope GH3 cells by focusing on the bone morphogenetic protein (BMP) system. Melatonin receptor activation, induced by melatonin and its receptor agonist ramelteon, significantly suppressed basal and forskolin-induced prolactin secretion and prolactin mRNA expression in GH3 cells. The melatonin MT2 receptor was predominantly expressed in GH3 cells, and the inhibitory effects of melatonin on prolactin production were reversed by treatment with the receptor antagonist luzindole, suggesting functional involvement of MT2 action in the suppression of prolactin release. Melatonin receptor activation also suppressed BMP-4-induced prolactin expression by inhibiting phosphorylation of Smad and transcription of the BMP-target gene Id-1, while BMP-4 treatment upregulated MT2 expression. Melatonin receptor activation suppressed basal, BMP-4-induced and forskolin-induced cAMP synthesis; however, BtcAMP-induced prolactin mRNA expression was not affected by melatonin or ramelteon, suggesting that MT2 activation leads to inhibition of prolactin production through the suppression of Smad signaling and cAMP synthesis. Experiments using intracellular signal inhibitors revealed that the ERK pathway is, at least in part, involved in prolactin induction by GH3 cells. Thus, a new regulatory role of melatonin involving BMP-4 in prolactin secretion was uncovered in lactotrope GH3 cells. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Receptor-like protein-tyrosine phosphatase alpha specifically inhibits insulin-increased prolactin gene expression

    DEFF Research Database (Denmark)

    Jacob, K K; Sap, J; Stanley, F M

    1998-01-01

    A physiologically relevant response to insulin, stimulation of prolactin promoter activity in GH4 pituitary cells, was used as an assay to study the specificity of protein-tyrosine phosphatase function. Receptor-like protein-tyrosine phosphatase alpha (RPTPalpha) blocks the effect of insulin...... is specific by two criteria. A number of potential RPTPalpha targets were ruled out by finding (a) that they are not affected or (b) that they are not on the pathway to insulin-increased prolactin-CAT activity. The negative effect of RPTPalpha on insulin activation of the prolactin promoter is not due...... to reduced phosphorylation or kinase activity of the insulin receptor or to reduced phosphorylation of insulin receptor substrate-1 or Shc. Inhibitor studies suggest that insulin-increased prolactin gene expression is mediated by a Ras-like GTPase but is not mitogen-activated protein kinase dependent...

  8. Histaminergic regulation of prolactin secretion

    DEFF Research Database (Denmark)

    Knigge, U P

    1990-01-01

    Histamine (HA), which acts as a neurotransmitter in the central nervous system, participates in the neuroendocrine regulation of prolactin (PRL) secretion. HA has a predominant stimulatory effect which is mediated via H2-receptors following central administration and via H1-receptors following...... systemic infusion of the amine. In addition, HA seems to exert a minor inhibitory effect on PRL secretion, an effect unmasked only during blockade of the receptor mediating the stimulatory effect. Following central administration the inhibitory effect is mediated via H1-receptors, while following systemic...... administration this effect is mediated via H2-receptors. In accordance with these findings, the H2-receptor antagonist cimetidine (CIM) has an inhibitory (following central administration) or stimulatory (following systemic administration) effect on PRL secretion. However, high doses of CIM possess an additional...

  9. Prolactin receptor attenuation induces zinc pool redistribution through ZnT2 and decreases invasion in MDA-MB-453 breast cancer cells

    International Nuclear Information System (INIS)

    Bostanci, Zeynep; Alam, Samina; Soybel, David I.; Kelleher, Shannon L.

    2014-01-01

    Prolactin receptor (PRL-R) activation regulates cell differentiation, proliferation, cell survival and motility of breast cells. Prolactin (PRL) and PRL-R over-expression are strongly implicated in breast cancer, particularly contributing to tumor growth and invasion in the more aggressive estrogen-receptor negative (ER−) disease. PRL-R antagonists have been suggested as potential therapeutic agents; however, mechanisms through which PRL-R antagonists exert their actions are not well-understood. Zinc (Zn) is a regulatory factor for over 10% of the proteome, regulating critical cell processes such as proliferation, cell signaling, transcription, apoptosis and autophagy. PRL-R signaling regulates Zn metabolism in breast cells. Herein we determined effects of PRL-R attenuation on cellular Zn metabolism and cell function in a model of ER-, PRL-R over-expressing breast cancer cells (MDA-MB-453). PRL-R attenuation post-transcriptionally increased ZnT2 abundance and redistributed intracellular Zn pools into lysosomes and mitochondria. ZnT2-mediated lysosomal Zn sequestration was associated with reduced matrix metalloproteinase 2 (MMP-2) activity and decreased invasion. ZnT2-mediated Zn accumulation in mitochondria was associated with increased mitochondrial oxidation. Our results suggest that PRL-R antagonism in PRL-R over-expressing breast cancer cells may reduce invasion through the redistribution of intracellular Zn pools critical for cellular function. - Highlights: • PRL-R attenuation increased ZnT2 expression. • PRL-R attenuation increased lysosomal and mitochondrial Zn accumulation. • PRL-R attenuation decreased MMP-2 and invasion. • PRL-R antagonists may modulate lysosomal and mitochondrial Zn pools

  10. Prolactin receptor attenuation induces zinc pool redistribution through ZnT2 and decreases invasion in MDA-MB-453 breast cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Bostanci, Zeynep, E-mail: zbostanci@hmc.psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); Alam, Samina, E-mail: sra116@psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); Soybel, David I., E-mail: dsoybel@hmc.psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); The Pennsylvania State University College of Medicine, Department of Cell and Molecular Physiology, 500 University Dr., Hershey, PA 17033 (United States); Kelleher, Shannon L., E-mail: slk39@psu.edu [The Pennsylvania State University, Department of Nutritional Sciences, 209 Chandlee Lab, University Park, PA 16802 (United States); The Pennsylvania State University Milton S. Hershey Medical Center, Department of Surgery, 500 University Dr., Hershey, PA 17033 (United States); The Pennsylvania State University College of Medicine, Department of Cell and Molecular Physiology, 500 University Dr., Hershey, PA 17033 (United States)

    2014-02-15

    Prolactin receptor (PRL-R) activation regulates cell differentiation, proliferation, cell survival and motility of breast cells. Prolactin (PRL) and PRL-R over-expression are strongly implicated in breast cancer, particularly contributing to tumor growth and invasion in the more aggressive estrogen-receptor negative (ER−) disease. PRL-R antagonists have been suggested as potential therapeutic agents; however, mechanisms through which PRL-R antagonists exert their actions are not well-understood. Zinc (Zn) is a regulatory factor for over 10% of the proteome, regulating critical cell processes such as proliferation, cell signaling, transcription, apoptosis and autophagy. PRL-R signaling regulates Zn metabolism in breast cells. Herein we determined effects of PRL-R attenuation on cellular Zn metabolism and cell function in a model of ER-, PRL-R over-expressing breast cancer cells (MDA-MB-453). PRL-R attenuation post-transcriptionally increased ZnT2 abundance and redistributed intracellular Zn pools into lysosomes and mitochondria. ZnT2-mediated lysosomal Zn sequestration was associated with reduced matrix metalloproteinase 2 (MMP-2) activity and decreased invasion. ZnT2-mediated Zn accumulation in mitochondria was associated with increased mitochondrial oxidation. Our results suggest that PRL-R antagonism in PRL-R over-expressing breast cancer cells may reduce invasion through the redistribution of intracellular Zn pools critical for cellular function. - Highlights: • PRL-R attenuation increased ZnT2 expression. • PRL-R attenuation increased lysosomal and mitochondrial Zn accumulation. • PRL-R attenuation decreased MMP-2 and invasion. • PRL-R antagonists may modulate lysosomal and mitochondrial Zn pools.

  11. Targeting Stromal Androgen Receptor Suppresses Prolactin-Driven Benign Prostatic Hyperplasia (BPH)

    Science.gov (United States)

    Lai, Kuo-Pao; Huang, Chiung-Kuei; Fang, Lei-Ya; Izumi, Kouji; Lo, Chi-Wen; Wood, Ronald; Kindblom, Jon; Yeh, Shuyuan

    2013-01-01

    Stromal-epithelial interaction plays a pivotal role to mediate the normal prostate growth, the pathogenesis of benign prostatic hyperplasia (BPH), and prostate cancer development. Until now, the stromal androgen receptor (AR) functions in the BPH development, and the underlying mechanisms remain largely unknown. Here we used a genetic knockout approach to ablate stromal fibromuscular (fibroblasts and smooth muscle cells) AR in a probasin promoter-driven prolactin transgenic mouse model (Pb-PRL tg mice) that could spontaneously develop prostate hyperplasia to partially mimic human BPH development. We found Pb-PRL tg mice lacking stromal fibromuscular AR developed smaller prostates, with more marked changes in the dorsolateral prostate lobes with less proliferation index. Mechanistically, prolactin mediated hyperplastic prostate growth involved epithelial-stromal interaction through epithelial prolactin/prolactin receptor signals to regulate granulocyte macrophage-colony stimulating factor expression to facilitate stromal cell growth via sustaining signal transducer and activator of transcription-3 activity. Importantly, the stromal fibromuscular AR could modulate such epithelial-stromal interacting signals. Targeting stromal fibromuscular AR with the AR degradation enhancer, ASC-J9®, led to the reduction of prostate size, which could be used in future therapy. PMID:23893956

  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. Effect of Sulpirid on blood serum prolactin- and TSH-levels

    International Nuclear Information System (INIS)

    Foldes, J.; Gyertyanfi, G.; Borvendeg, J.

    1979-01-01

    Euthyreoid and hyperthyreoid women were subjected to examinations investigating the effect of a dopamine-antagonist (Sulpirid) on serum TSH and prolactin (LTH)-levels. For measurements of serum concentrations the following kits were used: prolactine: CIS; TSH: Ria-mat-TSH (Byk-Mallinkrodt); thyroxine: Tiopac T 4 (Amersham); triiodothyronine: Ria-mat-T 3 (Byk-Mallinkrodt). Sulpirid increased both the LTH and the TSH-levels. In case of hyperthyreosis the effect of Sulpirid on LTH-levels was less pronounced and it had no effect on serum-TSH at all. Pre-treatment with a dopamine-agonist (Bromocryptin) impeded the effect of Sulpirid. It is concluded that dopamine-receptors do have a role in the regulation of TSH-secretion in the hypophysis. (L.E.)

  14. A combined computational and structural model of the full-length human prolactin receptor

    DEFF Research Database (Denmark)

    Bugge, Katrine Østergaard; Papaleo, Elena; Haxholm, Gitte Wolfsberg

    2016-01-01

    The prolactin receptor is an archetype member of the class I cytokine receptor family, comprising receptors with fundamental functions in biology as well as key drug targets. Structurally, each of these receptors represent an intriguing diversity, providing an exceptionally challenging target for...... 40 different receptor chains, and reveals that the extracellular domain is merely the tip of a molecular iceberg....

  15. Effects of deletion of the prolactin receptor on ovarian gene expression

    Directory of Open Access Journals (Sweden)

    Kelly Paul A

    2003-02-01

    Full Text Available Abstract Prolactin (PRL exerts pleiotropic physiological effects in various cells and tissues, and is mainly considered as a regulator of reproduction and cell growth. Null mutation of the PRL receptor (R gene leads to female sterility due to a complete failure of embryo implantation. Pre-implantatory egg development, implantation and decidualization in the mouse appear to be dependent on ovarian rather than uterine PRLR expression, since progesterone replacement permits the rescue of normal implantation and early pregnancy. To better understand PRL receptor deficiency, we analyzed in detail ovarian and corpora lutea development of PRLR-/- females. The present study demonstrates that the ovulation rate is not different between PRLR+/+ and PRLR-/- mice. The corpus luteum is formed but an elevated level of apoptosis and extensive inhibition of angiogenesis occur during the luteal transition in the absence of prolactin signaling. These modifications lead to the decrease of LH receptor expression and consequently to a loss of the enzymatic cascades necessary to produce adequate levels of progesterone which are required for the maintenance of pregnancy.

  16. 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....

  17. α-Estrogen and Progesterone Receptors Modulate Kisspeptin Effects on Prolactin: Role in Estradiol-Induced Prolactin Surge in Female Rats.

    Science.gov (United States)

    Aquino, Nayara S S; Araujo-Lopes, Roberta; Henriques, Patricia C; Lopes, Felipe E F; Gusmao, Daniela O; Coimbra, Candido C; Franci, Celso R; Reis, Adelina M; Szawka, Raphael E

    2017-06-01

    Kisspeptin (Kp) regulates prolactin (PRL) in an estradiol-dependent manner. We investigated the interaction between ovarian steroid receptors and Kp in the control of PRL secretion. Intracerebroventricular injections of Kp-10 or Kp-234 were performed in ovariectomized (OVX) rats under different hormonal treatments. Kp-10 increased PRL release and decreased 3,4-dihydroxyphenylacetic acid levels in the median eminence (ME) of OVX rats treated with estradiol (OVX+E), which was prevented by tamoxifen. Whereas these effects of Kp-10 were absent in OVX rats, they were replicated in OVX rats treated with selective agonist of estrogen receptor (ER)α, propylpyrazole triol, but not of ERβ, diarylpropionitrile. Furthermore, the Kp-10-induced increase in PRL was two times higher in OVX+E rats also treated with progesterone (OVX+EP), which was associated with a reduced expression of both tyrosine hydroxylase (TH) and Ser40-phosphorylated TH in the ME. Kp-10 also reduced dopamine levels in the ME of OVX+EP rats, an effect blocked by the progesterone receptor (PR) antagonist RU486. We also determined the effect of Kp antagonism with Kp-234 on the estradiol-induced surges of PRL and luteinizing hormone (LH), using tail-tip blood sampling combined with ultrasensitive enzyme-linked immunosorbent assay. Kp-234 impaired the early phase of the PRL surge and prevented the LH surge in OVX+E rats. Thus, we provide evidence that Kp stimulation of PRL release requires ERα and is potentiated by progesterone via PR activation. Moreover, alongside its essential role in the LH surge, Kp seems to play a role in the peak phase of the estradiol-induced PRL surge. Copyright © 2017 Endocrine Society.

  18. 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.

  19. 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

  20. Lack of effect of naloxone on prolactin and seizures in electroconvulsive therapy.

    Science.gov (United States)

    Sperling, M R; Melmed, S; McAllister, T; Price, T R

    1989-01-01

    Both opiate agonist and antagonist injection have been reported to modulate prolactin secretion, alter brain excitability and produce seizures, and modify the postictal state. We studied the effects of administration of high-dose naloxone, an opiate antagonist, on postictal prolactin levels, seizure duration, and postictal behavior, using patients undergoing electroconvulsive therapy (ECT) as a seizure model. Seven patients had 8 mg naloxone injected prior to one ECT treatment and saline injected prior to another treatment, with the order of injection randomized. Before ECT and 15 min after ECT, prolactin levels were drawn, and no blunting of the expected postictal prolactin elevation by naloxone injection was observed. We found no evidence that endogenous opiates trigger prolactin secretion during seizures. Seizure duration was also similar in saline and naloxone groups, and naloxone did not reverse postictal depression, as has been reported in an animal model.

  1. 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...

  2. 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.)

  3. 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....

  4. 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.)

  5. 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.

  6. Effects of arachidonic acid and 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine on prolactin secretion from anterior pituitary cells

    International Nuclear Information System (INIS)

    Camoratto, A.M.

    1988-01-01

    The role of two lipids, arachidonic acid and 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine, as modulators or prolactin secretion has been examined. Stimulators of phospholipase A 2 activity, melittin and mastoparan, were found to increase prolactin release. Melittin also caused release of previously incorporated 3 H-arachidonic acid and this effect was associated with loss of radiolabel from the phospholipid fraction. Exogenous arachidonic acid also stimulated prolactin secretion. Conversely, inhibitors of phospholipase A 2 activity, dibromoacetophenone and U10029A, decreased basal and stimulated prolactin release. Prolactin release could also be lowered by ETYA, BW755C and NDGA, inhibitors of arachidonic acid metabolism. In the second series of experiments the effects of the biologically active phospholipid 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine (platelet activating factor, PAF) on prolactin release were examined. PAF is an ether-linked phospholipid known to stimulate granule release in a variety of cell types including both inflammatory and noninflammatory cells. PAF increased release of prolactin from dispersed rat anterior pituitary cells; stimulation was not due to cell lysis. PAF-induced prolactin release could be blocked by the dopaminergic agonists apomorphine and bromocriptine as well as by two PAF receptor antagonists, SRI 63-072 and L-652-731

  7. 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

  8. 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.

  9. Region-specific expression and hormonal regulation of the first exon variants of rat prolactin receptor mRNA in rat brain and anterior pituitary gland.

    Science.gov (United States)

    Nogami, H; Hoshino, R; Ogasawara, K; Miyamoto, S; Hisano, S

    2007-08-01

    Recent studies have revealed the occurrence of five first exon variants of the rat prolactin receptor mRNA, suggesting that multiple promoters direct prolactin receptor transcription in response to different regulatory factors. In the present study, regional expression of these first exon variants, as well as two prolactin receptor subtypes generated by alternative splicing, was examined in the brains and anterior pituitary glands of female rats. Expression of the long-form was detected in the choroid plexus, hypothalamus, hippocampus, cerebral cortex and anterior pituitary gland, whereas the short form was detected only in the choroid plexus. E1-3 mRNA, a first exon variant, was detected in the choroid plexus, hypothalamus, and anterior pituitary gland, whereas E1-4 was detected only in the choroid plexus. Other variants were not detectable by the polymerase chain reaction protocol employed in this study. Ovariectomy increased the short form in the choroid plexus and the E1-3 expression in the choroid plexus and pituitary gland, but changes in the long-form and E1-4 expression were minimal. Replacement of oestrogens and prolactin suggest that oestrogens down-regulate E1-3 expression in the choroid plexus and pituitary gland, and that the negative effect of oestrogen is mediated by prolactin in the pituitary gland. The present results revealed the region-specific promoter usage in prolactin receptor mRNA transcription, as well as the involvement of oestrogens in the regulation of E1-3 mRNA expression in the brain and pituitary gland.

  10. 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....

  11. Regulation of dopamine D2 receptors in a novel cell line (SUP1)

    International Nuclear Information System (INIS)

    Ivins, K.J.; Luedtke, R.R.; Artymyshyn, R.P.; Molinoff, P.B.

    1991-01-01

    A prolactin-secreting cell line, SUP1, has been established from rat pituitary tumor 7315a. In radioligand binding experiments, the D2 receptor antagonist (S)-(-)-3- 125 I iodo-2-hydroxy-6-methoxy-N-[(1-ethyl-2- pyrrolidinyl)methyl]benzamide ( 125 I IBZM) labeled a single class of sites in homogenates of SUP1 cells (Kd = 0.6 nM; Bmax = 45 fmol/mg of protein). The sites displayed a pharmacological profile consistent with that of D2 receptors. Inhibition of the binding of 125 I IBZM by dopamine was sensitive to GTP, suggesting that D2 receptors in SUP1 cells are coupled to guanine nucleotide-binding protein(s). In the presence of isobutylmethylxanthine, dopamine decreased the level of cAMP accumulation in SUP1 cells. Dopamine also inhibited prolactin secretion from SUP1 cells. Both the inhibition of cAMP accumulation and the inhibition of prolactin secretion were blocked by D2 receptor antagonists, suggesting that these effects of dopamine were mediated by an interaction with D2 receptors. The regulation of D2 receptors in SUP1 cells by D2 receptor agonists was investigated. Exposure of SUP1 cells to dopamine or to the D2 receptor agonist N-propylnorapomorphine led to increased expression of D2 receptors, with no change in the affinity of the receptors for 125 I IBZM. An increase in the density of D2 receptors in SUP1 cells was evident within 7 hr of exposure to dopamine. Spiroperidol, a D2 receptor antagonist, blocked the effect of dopamine on receptor density. These results suggest that exposure of D2 receptors in SUP1 cells to agonists leads to an up-regulation of D2 receptors. Dopamine retained the ability to inhibit cAMP accumulation in SUP1 cells exposed to dopamine for 24 hr, suggesting that D2 receptors in SUP1 cells are not desensitized by prolonged exposure to agonist

  12. Prolactin receptors in Rip-cre cells, but not in AgRP neurones, are involved in energy homeostasis.

    Science.gov (United States)

    Ladyman, S R; MacLeod, M A; Khant Aung, Z; Knowles, P; Phillipps, H R; Brown, R S E; Grattan, D R

    2017-10-01

    Among its many functions, prolactin has been implicated in energy homeostasis, particularly during pregnancy and lactation. The arcuate nucleus is a key site in the regulation of energy balance. The present study aimed to examine whether arcuate nucleus neuronal populations involved in energy homeostasis are prolactin responsive and whether they can mediate the effects of prolactin on energy homeostasis. To determine whether Agrp neurones or Rip-Cre neurones are prolactin responsive, transgenic mice expressing the reporter td-tomato in Agrp neurones (td-tomato/Agrp-Cre) or Rip-Cre neurones (td-tomato/Rip-Cre) were treated with prolactin and perfused 45 minutes later. Brains were processed for double-labelled immunohistochemistry for pSTAT5, a marker of prolactin-induced intracellular signalling, and td-tomato. In addition, Agrp-Cre mice and Rip-Cre mice were crossed with mice in which the prolactin receptor gene (Prlr) was flanked with LoxP sites (Prlr lox/lox mice). The Prlr lox/lox construct was designed such that Cre-mediated recombination resulted in deletion of the Prlr and expression of green fluorescent protein (GFP) in its place. In td-tomato/Rip-Cre mice, prolactin-induced pSTAT5 was co-localised with td-tomato, indicating that there is a subpopulation of Rip-Cre neurones in the arcuate nucleus that respond to prolactin. Furthermore, mice with a specific deletion of Prlr in Rip-Cre neurones had lower body weights, increased oxygen consumption, increased running wheel activity and numerous cells in the arcuate nucleus had positive GFP staining indicating deletion of Prlr from Rip-Cre neurones. By contrast, no co-localisation of td-tomato and pSTAT5 was observed in td-tomato/Agrp-Cre mice after prolactin treatment. Moreover, Prlr lox/lox /Agrp-Cre mice had no positive GFP staining in the arcuate nucleus and did not differ in body weight compared to littermate controls. Overall, these results indicate that Rip-Cre neurones in the arcuate nucleus are

  13. 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.

  14. [Plasma prolactin concentration and the effect of metergoline in pseudopregnant Afghan hounds].

    Science.gov (United States)

    Okkens, A C; Dieleman, S J; Kooistra, H S; Bevers, M M

    2000-02-01

    The effects of metergoline, a 5-hydroxytryptamine (serotinin) antagonist, on the plasma concentrations of prolactin in overtly pseudopregnant Afghan hounds and on the clinical symptoms of overt pseudopregnancy were studied. Plasma concentrations of prolactin and progesterone were determined in six Afghan hounds with signs of overt pseudopregnancy for 2-3 weeks and in three Afghan hounds that were not pseudopregnant at the time of blood sampling. In the overtly pseudopregnant bitches the plasma concentrations of prolactin before treatment (35.5 +/- 8.5 micrograms l-1) were significantly higher than the plasma concentrations of prolactin of the three bitches that were not pseudopregnant (6.3 +/- 0.5 micrograms l-1); the latter values were similar to those of non-psueodopregnant beagle bitches during the total luteal phase. The six pseudopregnant Afghan hounds were treated for 10 days with the antiserotoninergic drug metergoline. At 2 h after the onset of treatment with metergoline, the mean plasma concentration of prolactin had decreased to 10.8 +/- 2.9 micrograms l-1. The plasma concentrations of prolactin continued to decline to 5.4 +/- 1.0 micrograms l-1 at 4 h and to 1.0 +/- 0.1 microgram l-1 during treatment days 3-10. Signs of pseudopregnancy, such as swelling of the mammary glands and digging, decreased during the treatment period. The treatment was associated with mild behavioural side effects such as whimpering and aggressiveness. These side effects are probably not related to suppression of prolactin but are due to a direct effect on serotoninergic pathways in the brain. It is concluded that high plasma concentrations of prolactin are associated with the development and maintenance of pseudopregnancy. The serotonin antagonist metergoline strongly suppresses plasma concentration of prolactine in pseudopregnant dogs and decreases the clinical signs of pseudopregnancy.

  15. Prolactin induces apoptosis of lactotropes in female rodents.

    Directory of Open Access Journals (Sweden)

    Jimena Ferraris

    Full Text Available Anterior pituitary cell turnover occurring during female sexual cycle is a poorly understood process that involves complex regulation of cell proliferation and apoptosis by multiple hormones. In rats, the prolactin (PRL surge that occurs at proestrus coincides with the highest apoptotic rate. Since anterior pituitary cells express the prolactin receptor (PRLR, we aimed to address the actual role of PRL in the regulation of pituitary cell turnover in cycling females. We showed that acute hyperprolactinemia induced in ovariectomized rats using PRL injection or dopamine antagonist treatment rapidly increased apoptosis and decreased proliferation specifically of PRL producing cells (lactotropes, suggesting a direct regulation of these cell responses by PRL. To demonstrate that apoptosis naturally occurring at proestrus was regulated by transient elevation of endogenous PRL levels, we used PRLR-deficient female mice (PRLRKO in which PRL signaling is totally abolished. According to our hypothesis, no increase in lactotrope apoptotic rate was observed at proestrus, which likely contributes to pituitary tumorigenesis observed in these animals. To decipher the molecular mechanisms underlying PRL effects, we explored the isoform-specific pattern of PRLR expression in cycling wild type females. This analysis revealed dramatic changes of long versus short PRLR ratio during the estrous cycle, which is particularly relevant since these isoforms exhibit distinct signaling properties. This pattern was markedly altered in a model of chronic PRLR signaling blockade involving transgenic mice expressing a pure PRLR antagonist (TGΔ1-9-G129R-hPRL, providing evidence that PRL regulates the expression of its own receptor in an isoform-specific manner. Taken together, these results demonstrate that i the PRL surge occurring during proestrus is a major proapoptotic signal for lactotropes, and ii partial or total deficiencies in PRLR signaling in the anterior pituitary

  16. The in vitro effect of prolactin on the growth, motility and expression of prolactin receptors in larvae of Toxocara canis.

    Science.gov (United States)

    Chávez-Güitrón, L E; Morales-Montor, J; Muñoz-Guzmán, M A; Nava-Castro, K E; Ramírez-Álvarez, H; Moreno-Méndoza, N A; Hernández-Cervantes, R; Alba-Hurtado, F

    2016-07-15

    The in vitro effect of prolactin (PRL) on the growth and motility of Toxocara canis larvae was assessed. Additionally, the expression and location of prolactin receptors (PRL-Rs) were determined in the larvae. Larvae of T. canis were incubated with different concentrations of PRL for different periods of time. The stimulated larvae accelerated their enlargement and increased their motility. The mean percentage of PRL-R+ cells in non-stimulated larvae, measured by flow cytometry was 7.3±0.3%. Compared with non-stimulated larvae, the mean fluorescence intensity (pPCR. The sequence of this fragment showed 99% similarity with the gene fragment that codes for the PRL-R of the domestic dog. A high concentration of PRL-Rs was immune-located in the posterior region of the larval intestine; therefore, the intestinal cells in this region were most likely the targets for this hormone. Based on these results, PRL-Rs were identified in T. canis larvae, and the in vitro stimulation with PRL increased the number of these receptors, accelerated the growth and modified the activity of larvae. All of the above suggest that T. canis larvae are evolutionarily adapted to recognize the PRL of their definitive host and furthermore might explain the reactivation of tissue-arrested larvae during the gestation of bitches, which does not occur in gestating females of other species. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. PROLACTIN-INDUCED TYROSINE PHOSPHORYLATION, ACTIVATION AND RECEPTOR ASSOCIATION OF FOCAL ADHESION KINASE (FAK) IN MAMMARY EPITHELIAL CELLS

    Science.gov (United States)

    Prolactin-Induced Tyrosine Phosphorylation, Activation and ReceptorAssociation of Focal Adhesion Kinase (FAK) in Mammary Epithelial Cells. Suzanne E. Fenton1 and Lewis G. Sheffield2. 1U.S. Environmental ProtectionAgency, MD-72, Research Triangle Park, NC 27711, and

  18. A pigeon crop sac radioreceptor assay for prolactin

    International Nuclear Information System (INIS)

    Forsyth, I.A.; Buntin, J.D.; Nicoll, C.S.

    1978-01-01

    Ovine prolactin, labelled with 125 I by either lactoperoxidase or a mild chloramine T method, was bound to receptors from the pigeon crop sac mucosa cells of prolactin-injected pigeons. Binding was demonstrated in a crude homogenate of mucosal cells removed from the crop by scraping and in a subcellular fraction in which 5'- nucleotidase activity was enhanced two- to three-fold. The binding was specific, dependent on time, temperature and the concentration of receptors and had a dissociation constant of 7 x 10 -10 mol/l. The binding capacity of the crop tissue was 71 fmol/mg membrane protein. Nine purified preparations of prolactin from four species were assayed by local pigeon crop sac bioassay and by radioreceptor assay. The two methods were highly correlated (r = 0.934). The regression equation was radioreceptor assay = 1.22 bioassay - 0.18 indicating a 1:1 correspondence between the two methods for prolactin purified from sheep, rat, horse and pig anterior pituitary glands. (author)

  19. Convergent Evolution of Slick Coat in Cattle through Truncation Mutations in the Prolactin Receptor

    Directory of Open Access Journals (Sweden)

    Laercio R. Porto-Neto

    2018-02-01

    Full Text Available Evolutionary adaptations are occasionally convergent solutions to the same problem. A mutation contributing to a heat tolerance adaptation in Senepol cattle, a New World breed of mostly European descent, results in the distinct phenotype known as slick, where an animal has shorter hair and lower follicle density across its coat than wild type animals. The causal variant, located in the 11th exon of prolactin receptor, produces a frameshift that results in a truncated protein. However, this mutation does not explain all cases of slick coats found in criollo breeds. Here, we obtained genome sequences from slick cattle of a geographically distinct criollo breed, namely Limonero, whose ancestors were originally brought to the Americas by the Spanish. These data were used to identify new causal alleles in the 11th exon of the prolactin receptor, two of which also encode shortened proteins that remove a highly conserved tyrosine residue. These new mutations explained almost 90% of investigated cases of animals that had slick coats, but which also did not carry the Senepol slick allele. These results demonstrate convergent evolution at the molecular level in a trait important to the adaptation of an animal to its environment.

  20. 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, ...

  1. Effect of gonadotrophin inhibiting material isolated from human urine on action of prolactin at rat Leydig cell

    Energy Technology Data Exchange (ETDEWEB)

    Bagli, N P; Rajendran, K G; Shah, P N [Cancer Research Inst., Bombay (India). Div. of Endocrinology

    1980-05-01

    To study the effect of gonadotropin inhibiting material (GIM) on the binding of prolactin to Leydig cell receptors isolated Leydig cells were incubated with sup(125)I-prolactin. Presence of GIM in the incubation mixture did not inhibit the binding of sup(125)I-prolactin to Leydig cells whereas unlabelled prolactin significantly reduced the binding. In another experiment, testicular cells were incubated with FITC-tagged GIM. Binding of GIM to Leydig cells was seen by the presence of fluorescence on these cells. This binding could be inhibited by untagged GIM but not by prolactin. The results suggest the presence of separate receptors for GIM and prolactin on the Leydig cells and indicate that termination of pregnancy by GIM is not due to any interference with prolactin binding to its receptors.

  2. Plasma concentrations of prolactin in overtly pseudopregnant Afghan hounds and the effect of metergoline.

    Science.gov (United States)

    Okkens, A C; Dieleman, S J; Kooistra, H S; Bevers, M M

    1997-01-01

    The effect of metergoline, a 5-hydroxytryptamine (serotonin) antagonist, on the plasma concentrations of prolactin in overtly pseudopregnant Afghan hounds and on the clinical symptoms of overt pseudopregnancy were studied. Plasma concentrations of prolactin and progesterone were determined in six Afghan hounds with signs of overt pseudopregnancy for 2-3 weeks and in three Afghan hounds that were not pseudopregnant at the time of blood sampling. In the overtly pseudopregnant bitches the plasma concentrations of prolactin before treatment (35.5 +/- 8.5 micrograms l-1) were significantly higher than the plasma concentrations of prolactin of the three bitches that were not pseudopregnant (6.3 +/- 0.5 micrograms l-1); the latter values were similar to those of non-pseudopregnant beagle bitches during the total luteal phase. The six pseudopregnant Afghan hounds were treated for 10 days with the antiserotoninergic drug metergoline. At 2 h after the onset of treatment with metergoline, the mean plasma concentration of prolactin had decreased to 10.8 +/- 2.9 micrograms l-1. The plasma concentrations of prolactin continued to decline to 5.4 +/- 1.0 micrograms l-1 at 4 h and to 1.0 +/- 0.1 microgram l-1 during treatment days 3-10. Signs of pseudopregnancy, such as swelling of the mammary glands and digging, decreased during the treatment period. The treatment was associated with mild behavioural side effects such as whimpering and aggressiveness. These side effects are probably not related to suppression of prolactin but are due to a direct effect on serotoninergic pathways in the brain. It is concluded that high plasma concentrations of prolactin are associated with the development and maintenance of pseudopregnancy. The serotonin antagonist metergoline strongly suppresses plasma concentrations of prolactin in pseudopregnant dogs and decreases the clinical signs of pseudopregnancy.

  3. Crystal structure of an affinity-matured prolactin complexed to its dimerized receptor reveals the topology of hormone binding site 2

    DEFF Research Database (Denmark)

    Broutin, Isabelle; Jomain, Jean-Baptiste; Tallet, Estelle

    2010-01-01

    We report the first crystal structure of a 1:2 hormone.receptor complex that involves prolactin (PRL) as the ligand, at 3.8-A resolution. Stable ternary complexes were obtained by generating affinity-matured PRL variants harboring an N-terminal tail from ovine placental lactogen, a closely relate...... and prostate cancer.......We report the first crystal structure of a 1:2 hormone.receptor complex that involves prolactin (PRL) as the ligand, at 3.8-A resolution. Stable ternary complexes were obtained by generating affinity-matured PRL variants harboring an N-terminal tail from ovine placental lactogen, a closely related...... PRL receptor (PRLR) ligand. This structure allows one to draw up an exhaustive inventory of the residues involved at the PRL.PRLR site 2 interface, consistent with all previously reported site-directed mutagenesis data. We propose, with this description, an interaction model involving three structural...

  4. From Bench to Bedside: Translating the Prolactin/Vasoinhibin Axis

    Directory of Open Access Journals (Sweden)

    Jakob Triebel

    2017-12-01

    Full Text Available The prolactin/vasoinhibin axis defines an endocrine system, in which prolactin (PRL and vasoinhibins regulate blood vessel growth and function, the secretion of other hormones, inflammatory and immune processes, coagulation, and behavior. The core element of the PRL/vasoinhibin axis is the generation of vasoinhibins, which consists in the proteolytic cleavage of their precursor molecule PRL. Vasoinhibins can interact with multiple different partners to mediate their effects in various tissues and anatomical compartments, indicating their pleiotropic nature. Based on accumulating knowledge about the PRL/vasoinhibin axis, two clinical trials were initiated, in which vasoinhibin levels are the target of therapeutic interventions. One trial investigates the effect of levosulpiride, a selective dopamine D2-receptor antagonist, on retinal alterations in patients with diabetic macular edema and retinopathy. The rationale of this trial is that the levosulpiride-induced hyperprolactinemia resulting in increased retinal vasoinhibins could lead to beneficiary outcomes in terms of a vasoinhibin-mediated antagonization of diabetes-induced retinal alterations. Another trial investigated the effect of bromocriptine, a dopamine D2-receptor agonist, for the treatment of peripartum cardiomyopathy. The rationale of treatment with bromocriptine is the inhibition of vasoinhibin generation by substrate depletion to prevent detrimental effects on the myocardial microvascularization. The trial demonstrated that bromocriptine treatment was associated with a high rate of left ventricular recovery and low morbidity and mortality. Therapeutic interventions into the PRL/vasoinhibin axis bear the risk of side effects in the areas of blood coagulation, blood pressure, and alterations of the mental state.

  5. 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

  6. Characterization of ductal and lobular breast carcinomas using novel prolactin receptor isoform specific antibodies

    Directory of Open Access Journals (Sweden)

    Heger Christopher D

    2010-12-01

    Full Text Available Abstract Background Prolactin is a polypeptide hormone responsible for proliferation and differentiation of the mammary gland. More recently, prolactin's role in mammary carcinogenesis has been studied with greater interest. Studies from our laboratory and from others have demonstrated that three specific isoforms of the prolactin receptor (PRLR are expressed in both normal and cancerous breast cells and tissues. Until now, reliable isoform specific antibodies have been lacking. We have prepared and characterized polyclonal antibodies against each of the human PRLR isoforms that can effectively be used to characterize human breast cancers. Methods Rabbits were immunized with synthetic peptides of isoform unique regions and immune sera affinity purified prior to validation by Western blot and immunohistochemical analyses. Sections of ductal and lobular carcinomas were stained with each affinity purified isoform specific antibody to determine expression patterns in breast cancer subclasses. Results We show that the rabbit antibodies have high titer and could specifically recognize each isoform of PRLR. Differences in PRLR isoform expression levels were observed and quantified using histosections from xenografts of established human breast cancer cells lines, and ductal and lobular carcinoma human biopsy specimens. In addition, these results were verified by real-time PCR with isoform specific primers. While nearly all tumors contained LF and SF1b, the majority (76% of ductal carcinoma biopsies expressed SF1a while the majority of lobular carcinomas lacked SF1a staining (72% and 27% had only low levels of expression. Conclusions Differences in the receptor isoform expression profiles may be critical to understanding the role of PRL in mammary tumorigenesis. Since these antibodies are specifically directed against each PRLR isoform, they are valuable tools for the evaluation of breast cancer PRLR content and have potential clinical importance in

  7. Interactions between prolactin and kisspeptin to control reproduction.

    Science.gov (United States)

    Donato, Jose; Frazão, Renata

    2016-01-01

    Prolactin is best known for its effects of stimulating mammary gland development and lactogenesis. However, prolactin is a pleiotropic hormone that is able to affect several physiological functions, including fertility. Prolactin receptors (PRLRs) are widely expressed in several tissues, including several brain regions and reproductive tract organs. Upon activation, PRLRs may exert prolactin's functions through several signaling pathways, although the recruitment of the signal transducer and activator of transcription 5 causes most of the known effects of prolactin. Pathological hyperprolactinemia is mainly due to the presence of a prolactinoma or pharmacological effects induced by drugs that interact with the dopamine system. Notably, hyperprolactinemia is a frequent cause of reproductive dysfunction and may lead to infertility in males and females. Recently, several studies have indicated that prolactin may modulate the reproductive axis by acting on specific populations of hypothalamic neurons that express the Kiss1 gene. The Kiss1 gene encodes neuropeptides known as kisspeptins, which are powerful activators of gonadotropin-releasing hormone neurons. In the present review, we will summarize the current knowledge about prolactin's actions on reproduction. Among other aspects, we will discuss whether the interaction between prolactin and the Kiss1-expressing neurons can affect reproduction and how kisspeptins may become a novel therapeutic approach to treat prolactin-induced infertility.

  8. 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.

  9. 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

  10. 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

  11. 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...

  12. 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.

  13. Pituitary Androgen Receptor Signalling Regulates Prolactin but Not Gonadotrophins in the Male Mouse

    Science.gov (United States)

    O’Hara, Laura; Curley, Michael; Tedim Ferreira, Maria; Cruickshanks, Lyndsey; Milne, Laura; Smith, Lee B.

    2015-01-01

    Production of the androgen testosterone is controlled by a negative feedback loop within the hypothalamic-pituitary-gonadal (HPG) axis. Stimulation of testicular Leydig cells by pituitary luteinising hormone (LH) is under the control of hypothalamic gonadotrophin releasing hormone (GnRH), while suppression of LH secretion by the pituitary is controlled by circulating testosterone. Exactly how androgens exert their feedback control of gonadotrophin secretion (and whether this is at the level of the pituitary), as well as the role of AR in other pituitary cell types remains unclear. To investigate these questions, we exploited a transgenic mouse line (Foxg1Cre/+; ARfl/y) which lacks androgen receptor in the pituitary gland. Both circulating testosterone and gonadotrophins are unchanged in adulthood, demonstrating that AR signalling is dispensable in the male mouse pituitary for testosterone-dependent regulation of LH secretion. In contrast, Foxg1Cre/+; ARfl/y males have a significant increase in circulating prolactin, suggesting that, rather than controlling gonadotrophins, AR-signalling in the pituitary acts to suppress aberrant prolactin production in males. PMID:25799562

  14. Prolactin modulates luteal activity in the short-nosed fruit bat, Cynopterus sphinx during delayed embryonic development.

    Science.gov (United States)

    Anuradha; Krishna, Amitabh

    2017-07-01

    The aim of this study was to evaluate the role of prolactin as a modulator of luteal steroidogenesis during the period of delayed embryonic development in Cynopterus sphinx. A marked decline in circulating prolactin levels was noted during the months of November through December coinciding with the period of decreased serum progesterone and delayed embryonic development. The seasonal changes in serum prolactin levels correlated positively with circulating progesterone (P) level, but inversely with circulating melatonin level during first pregnancy showing delayed development in Cynopterus sphinx. The results also showed decreased expression of prolactin receptor-short form (PRL-RS) both in the corpus luteum and in the utero-embryonic unit during the period of delayed embryonic development. Bats treated in vivo with prolactin during the period of delayed development showed significant increase in serum progesterone and estradiol levels together with significant increase in the expression of PRL-RS, luteinizing hormone receptor (LH-R), steroidogenic acute receptor protein (STAR) and 3β-hydroxysteroid dehydrogenase (3β-HSD) in the ovary. Prolactin stimulated ovarian angiogenesis (vascular endothelial growth factor) and cell survival (B-cell lymphoma 2) in vivo. Significant increases in ovarian progesterone production and the expression of prolactin-receptor, LH-R, STAR and 3β-HSD proteins were noted following the exposure of LH or prolactin in vitro during the delayed period. In conclusion, short-day associated increased melatonin level may be responsible for decreased prolactin release during November-December. The decline in prolactin level might play a role in suppressing P and estradiol-17β (E2) estradiol levels thereby causing delayed embryonic development in C. sphinx. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. 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.

  16. 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.

  17. Prolactin receptors in liver, kidney, and gill of the tilapia (Oreochromis mossambicus): Characterization and effect of salinity on specific binding of iodinated ovine prolactin

    International Nuclear Information System (INIS)

    Dauder, S.; Young, G.; Hass, L.; Bern, H.A.

    1990-01-01

    Specific binding of 125 I-ovine prolactin (oPRL) to microsomal fractions from gill, kidney, and liver of adult tilapia was determined. Specific binding varied among tissues, the highest values being displayed by kidney membranes. In the liver, the binding of oPRL was not strongly displaced by tilapia prolactins (tPRL177 and tPRL188), although tPRL177 was six times more potent than tPRL188. On the other hand, in kidney and gill membranes, the two tPRLs were equipotent. Tilapia PRLs showed low potency in competing for oPRL-binding sites when pregnant rat liver membranes were utilized. Tilapia growth hormone (tGH) and human growth hormone (hGH) displaced 125 I-oPRL from liver as well as did tPRL177 but were not recognized well by renal or branchial receptors. Two 125 I-oPRL-binding sites were detected in every tissue tested. These binding sites are subject to physiological regulation since adaptation to seawater resulted in a significant decrease in specific binding

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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 ...

  7. 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

  8. Cadmium mimics estrogen-driven cell proliferation and prolactin secretion from anterior pituitary cells.

    Directory of Open Access Journals (Sweden)

    Sonia A Ronchetti

    Full Text Available Cadmium (Cd is a heavy metal of considerable occupational and environmental concern affecting wildlife and human health. Recent studies indicate that Cd, like other heavy metals, can mimic effects of 17β-estradiol (E2 involving E2 receptor (ER activation. Lactotrophs, the most abundant cell type in anterior pituitary gland, are the main target of E2, which stimulates cell proliferation and increases prolactin secretion through ERα. The aim of this work was to examine whether Cd at nanomolar concentrations can induce cell proliferation and prolactin release in anterior pituitary cells in culture and whether these effects are mediated through ERs. Here we show that 10 nM Cd was able to stimulate lactotroph proliferation in anterior pituitary cell cultures from female Wistar rats and also in GH3 lactosomatotroph cell line. Proliferation of somatotrophs and gonadotrophs were not affected by Cd exposure. Cd promoted cell cycle progression by increasing cyclins D1, D3 and c-fos expression. Cd enhanced prolactin synthesis and secretion. Cd E2-like effects were blocked by the pure ERs antagonist ICI 182,780 supporting that Cd acts through ERs. Further, both Cd and E2 augmented full-length ERαexpression and its 46 kDa-splicing variant. In addition, when co-incubated Cd was shown to interact with E2 by inducing ERα mRNA expression which indicates an additive effect between them. This study shows for the first time that Cd at nanomolar concentration displays xenoestrogenic activities by inducing cell growth and stimulating prolactin secretion from anterior pituitary cells in an ERs-dependent manner. Cd acting as a potent xenoestrogen can play a key role in the aetiology of different pathologies of the anterior pituitary and in estrogen-responsive tissues which represent considerable risk to human health.

  9. 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 ...

  10. 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

  11. POLYMORPHISM OF PROLACTIN RECEPTOR GENE (PRLR IN THE POLISH LANDRACE AND POLISH LARGE WHITE SWINE POPULATION AND REPRODUCTIVE TRAITS

    Directory of Open Access Journals (Sweden)

    AGATA ZIÓŁKOWSKA

    2011-01-01

    Full Text Available Prolactin receptor gene was found in pig chromosome 16, and it is one of the genes with a significant effect on reproduction traits in sows. The objective of the research was to determine polymorphism of the prolactin receptor gene in pigs of two maternal breeds: Polish Landrace and Polish Large White, as well as analyse relations between particular allelomorphic variants, and reproduction traits of examined sows. Two PRLR gene alleles, A and B, were isolated, they were obtained after AluI restriction gene digestion of the PCR product with the length of 163 bp; furthermore, three genotypes were identified: PRLRAA – 85, 59, 19 bp; PRLRAB – 104, 85, 59, 19 bp; PRLRBB – 104, 59 bp. We assessed 122 sows, in terms of their age at the first farrowing, as well as the sizes of the two subsequent litters. No statistically significant differences were found in the examined reproduction traits in sows with different allelomorphic relations, both within each breed and between breeds. Obtained results indicate that it is necessary to conduct further research on a larger animal group.

  12. 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.

  13. 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....

  14. 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.

  15. 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

  16. 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.

  17. Receptor mapping in psychiatric patients with SPECT

    International Nuclear Information System (INIS)

    Schlegel, S.

    1997-01-01

    This paper summarizes some data of our studies with the single-photon-emission-computerized tomography (SPECT), focussing on the dopamine-D2- and the benzodiazepine receptor mapping. Benzodiazepine receptors: Central benzodiazepine receptors (BZr) can be visualized with iomazenil which is an analogue of the benzodiazepine antagonist flumazenil, labeled with 123-iodine. Since the involvement of the BZr system is discussed in the pathogenesis of anxiety and depression, patients with these disorders were investigated. A third study investigated the BZr-occupancy during benzodiazepine treatment (lorazepam). Results: (a) Patients with panic disorders had lower iomazenil uptake values compared to epileptic patients. (b) Depressed patients showed a positive correlation between severity of illness and frontal uptake. (c) BZr occupancy during lorazepam treatment was measurable, but not associated with lorazepam plasma levels. Dopamine-D2-receptors: With 123-I-iodobenzamide (IBZM), and iodine-labeled dopamine receptor ligand, the D2 receptor density can be measured by a semiquantitative approach (striatum/frontal cortex=ST/FC). Therefore, we investigated the D2-receptor occupancy during treatment with typical and atypical neuroleptics in relationship to dosages (normalized with different formulas of chlorpromazine equivalents), side effects, and prolactin plasma levels. Results: Dependent on the selected formula for chlorpromazine equivalents, the ST/FC ratio was correlated with dosages. Side effects and prolactin plasma levels showed a negative association with lower ST/FC ratios. (orig.) [de

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Prolactins, ch. 11

    International Nuclear Information System (INIS)

    Friesen, H.; Guyda, H.; Hwang, P.

    1976-01-01

    A radioimmunoassay for primate prolactin is described. Synthesis, secretion and immunological properties of prolactin in comparison to the human growth hormone and separation of the two are studied using 3 H-L-leucine. Prolactin was labelled with 131 I by the chloramine-T method of Hunter and Greenwood. Purification was performed by a sepharose column, coupled with antibodies to ovine prolactine from which the prolactin is subsequently eluted. The assay procedure and the cross-reactivity of different materials in the assay are described. Prolactin concentrations in healthy people, patients and pregnant women (amniotic fluid) are examined

  3. Agnus castus extracts inhibit prolactin secretion of rat pituitary cells.

    Science.gov (United States)

    Sliutz, G; Speiser, P; Schultz, A M; Spona, J; Zeillinger, R

    1993-05-01

    In our studies on prolactin inhibition by plant extracts we focused on the effects of extracts of Vitex agnus castus and its preparations on rat pituitary cells under basal and stimulated conditions in primary cell culture. Both extracts from Vitex agnus castus as well as synthetic dopamine agonists (Lisuride) significantly inhibit basal as well as TRH-stimulated prolactin secretion of rat pituitary cells in vitro and as a consequence inhibition of prolactin secretion could be blocked by adding a dopamine receptor blocker. Therefore because of its dopaminergic effect Agnus castus could be considered as an efficient alternative phytotherapeutic drug in the treatment of slight hyperprolactinaemia.

  4. 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.

  5. 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.

  6. 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...

  7. Progesterone receptors (PR) mediate STAT actions: PR and prolactin receptor signaling crosstalk in breast cancer models.

    Science.gov (United States)

    Leehy, Katherine A; Truong, Thu H; Mauro, Laura J; Lange, Carol A

    2018-02-01

    Estrogen is the major mitogenic stimulus of mammary gland development during puberty wherein ER signaling acts to induce abundant PR expression. PR signaling, in contrast, is the primary driver of mammary epithelial cell proliferation in adulthood. The high circulating levels of progesterone during pregnancy signal through PR, inducing expression of the prolactin receptor (PRLR). Cooperation between PR and prolactin (PRL) signaling, via regulation of downstream components in the PRL signaling pathway including JAKs and STATs, facilitates the alveolar morphogenesis observed during pregnancy. Indeed, these pathways are fully integrated via activation of shared signaling pathways (i.e. JAKs, MAPKs) as well as by the convergence of PRs and STATs at target genes relevant to both mammary gland biology and breast cancer progression (i.e. proliferation, stem cell outgrowth, tissue cell type heterogeneity). Thus, rather than a single mediator such as ER, transcription factor cascades (ER>PR>STATs) are responsible for rapid proliferative and developmental programming in the normal mammary gland. It is not surprising that these same mediators typify uncontrolled proliferation in a majority of breast cancers, where ER and PR are most often co-expressed and may cooperate to drive malignant tumor progression. This review will primarily focus on the integration of PR and PRL signaling in breast cancer models and the importance of this cross-talk in cancer progression in the context of mammographic density. Components of these PR/PRL signaling pathways could offer alternative drug targets and logical complements to anti-ER or anti-estrogen-based endocrine therapies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Effects of cortisol, growth hormone and prolactin on gill claudin expression in Atlantic salmon

    DEFF Research Database (Denmark)

    Tipsmark, Christian Kølbæk; Jørgensen, Charlotte; Brande-Lavridsen, Nanna

    2009-01-01

    We recently showed that a series of tight junction proteins of the claudin family are regulated in the gill of salmon during salinity acclimation. The aim of the present study was to investigate the role of cortisol, growth hormone (GH) and prolactin (PRL) on regulation of expression of these iso......We recently showed that a series of tight junction proteins of the claudin family are regulated in the gill of salmon during salinity acclimation. The aim of the present study was to investigate the role of cortisol, growth hormone (GH) and prolactin (PRL) on regulation of expression...... antagonists RU486 and spironolactone, respectively. The observed in vitro responses were blocked by RU486, suggesting the involvement of a glucocorticoid type receptor. Injections of FW salmon with cortisol increased the expression of claudin 10e, 27a, and 30 but did not affect claudin 28a and 28b...... significantly. While GH had no effect on its own, the combination of GH and cortisol reduced claudin 28b levels. Injection of SW salmon with PRL selectively increased the expression of claudin 28a but had no effect on the other examined isoforms. The data shows that FW- (27a and 30) and SW-induced (10e...

  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. 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,

  11. Differences in both glycosylation and binding properties between rat and mouse liver prolactin receptors.

    Science.gov (United States)

    Lascols, O; Cherqui, G; Munier, A; Picard, J; Capeau, J

    1994-05-01

    To investigate whether glycanic chains of prolactin receptors (PRL-R) play a role in hormone binding activity, comparison was made of rat and mouse liver solubilized receptors with respect to both their affinity for the hormone and their glycosylation properties. As compared with rat receptors, mouse receptors exhibited a 2-fold higher affinity for human growth hormone (hGH), the hormone being bound by both tissues with a lactogenic specificity. Along with this increased affinity, mouse receptors had a 2 lower M(r) relative to rat receptors (62 kDa versus 64 kDa as measured on hGH cross-linked receptors). These differences could be ascribed to different glycosylation properties of the receptors from the two species, as supported by the followings. 1) After treatment with endoglycosidase F (endo F), rat and mouse PRL-R no longer exhibited any difference in their M(r) (54 kDa for both cross-linked receptors). 2) Neuraminidase treatment increased by 37% the binding of hGH to mouse receptors, but was ineffective on the hormone-binding to rat receptors. Conversely, wheat germ agglutinin (WGA), another sialic acid specific probe, decreased hGH binding to rat receptors by 25%, but had no effect on this process for mouse ones. 3) Marked differences were observed in the recoveries of rat and mouse hormone-receptor (HR) complexes from ricin-1- (RCA1-), concanavalin A- (ConA-) and WGA-immobilized lectins. These differences were reduced (RCA1 and ConA) or abolished (WGA) after rat and mouse receptor desialylation by neuraminidase, a treatment which decreased the M(r) of both receptors by 2 kDa. Taken together, these results strongly suggest that the PRL-R from rat and mouse liver contain biantennary N-linked oligosaccharidic chains with distinct type of sialylation, which may account for their differential hormone-binding affinities.

  12. 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.

  13. 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.)

  14. 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.

  15. 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...

  16. 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.

  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. 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.

  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. 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.

  1. 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

  2. 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

  3. 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...

  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

    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.)

  5. Prolactin promotes breast cancer cell migration through actin cytoskeleton remodeling

    Directory of Open Access Journals (Sweden)

    Priscilla Ludovico da Silva

    2015-12-01

    Full Text Available The role of prolactin on breast cancer development and progression is debated. Breast cancer progression largely depends on cell movement and on the ability to remodel the actin cytoskeleton. In this process, actin-binding proteins are requested to achieve fibrillar actin de-polymerization and relocation at the cell membrane. Kinases such as focal adhesion kinase (FAK are later required to form actin/vinculin-enriched structures called focal adhesion complexes, which mediate firm adhesion to the extracellular matrix. These controllers are regulated by c-Src, which forms multiprotein signaling complexes with membrane receptors and is regulated by a number of hormones, including prolactin. We here show that breast cancer cells exposed to prolactin display an elevated c-Src expression and phosphorylation. In parallel, increased moesin and FAK expression and phosphorylation are found. These molecular changes are associated to relocation to the plasma membrane of cytoskeletal actin fibers and to increased horizontal cell movement. In conclusion, prolactin regulates actin remodeling and enhances breast cancer cell movement. This finding broadens the understanding of prolactin actions on breast cancer cells, highlighting new pathways that may be relevant to on breast cancer progression.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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.

  17. 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

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Are sexual side effects of prolactin-raising antipsychotics reducible to serum prolactin?

    NARCIS (Netherlands)

    Knegtering, Henderikus; van den Bosch, Rob; Castelein, Stynke; Bruggeman, Richard; Sytema, Sjoerd; van Os, Jim

    Objective: To assess the degree to which sexual side effects (SSE) are associated with prolactin-raising antipsychotics, and to what degree such SSE are reducible to serum prolactin levels. Method: A large sample (n = 264) of patients treated for 6 weeks with protactin-raising and prolactin-sparing

  6. 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.

  7. 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.

  8. McCune-Albright syndrome: growth hormone and prolactin hypersecretion.

    Science.gov (United States)

    Christoforidis, Athanasios; Maniadaki, Ilianna; Stanhope, Richard

    2006-05-01

    McCune-Albright syndrome (MAS) has a special interest for endocrinologists as its pathogenesis results in hypersecretion of hormones in peripheral endocrine tissues. This can be expressed as precocious puberty, mainly in girls, primary hyperthyroidism, growth hormone (GH) and/or prolactin excess, hyperparathyroidism and hypercortisolism. The incidence of GH excess among patients with MAS has been assessed as up to 21%. The pathogenesis of GH hypersecretion in MAS is not completely understood, whereas it seems to be different from the aetiology of acromegaly/gigantism in non-MAS patients. The clinical expression of GH excess can be masked because of precocious puberty or craniofacial fibrous dysplasia, indicating the necessity for screening. Medical treatment is usually the only option in MAS patients with GH excess, as transsphenoidal surgery is usually restricted due to massive thickening of the skull base, whereas radiotherapy is contraindicated due to probable higher predisposition to sarcomatous transformation. The use of bromocriptine, cabergoline and octreotide, or the combination of these, has shown variable results, whereas pegvisomant, a GH receptor antagonist, is a new promising option, although not yet used in patients with MAS.

  9. 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%

  10. 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

  11. 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

  12. 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...

  13. The hormone prolactin is a novel, endogenous trophic factor able to regulate reactive glia and to limit retinal degeneration.

    Science.gov (United States)

    Arnold, Edith; Thebault, Stéphanie; Baeza-Cruz, German; Arredondo Zamarripa, David; Adán, Norma; Quintanar-Stéphano, Andrés; Condés-Lara, Miguel; Rojas-Piloni, Gerardo; Binart, Nadine; Martínez de la Escalera, Gonzalo; Clapp, Carmen

    2014-01-29

    Retinal degeneration is characterized by the progressive destruction of retinal cells, causing the deterioration and eventual loss of vision. We explored whether the hormone prolactin provides trophic support to retinal cells, thus protecting the retina from degenerative pressure. Inducing hyperprolactinemia limited photoreceptor apoptosis, gliosis, and changes in neurotrophin expression, and it preserved the photoresponse in the phototoxicity model of retinal degeneration, in which continuous exposure of rats to bright light leads to retinal cell death and retinal dysfunction. In this model, the expression levels of prolactin receptors in the retina were upregulated. Moreover, retinas from prolactin receptor-deficient mice exhibited photoresponsive dysfunction and gliosis that correlated with decreased levels of retinal bFGF, GDNF, and BDNF. Collectively, these data unveiled prolactin as a retinal trophic factor that may regulate glial-neuronal cell interactions and is a potential therapeutic molecule against retinal degeneration.

  14. 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

  15. Adenosine A1 receptor-mediated inhibition of in vitro prolactin secretion from the rat anterior pituitary

    Directory of Open Access Journals (Sweden)

    D.L.W. Picanço-Diniz

    2006-11-01

    Full Text Available In previous studies, we demonstrated biphasic purinergic effects on prolactin (PRL secretion stimulated by an adenosine A2 agonist. In the present study, we investigated the role of the activation of adenosine A1 receptors by (R-N6-(2-phenylisopropyladenosine (R-PIA at the pituitary level in in vitro PRL secretion. Hemipituitaries (one per cuvette in five replicates from adult male rats were incubated. Administration of R-PIA (0.001, 0.01, 0.1, 1, and 10 µM induced a reduction of PRL secretion into the medium in a U-shaped dose-response curve. The maximal reduction was obtained with 0.1 µM R-PIA (mean ± SEM, 36.01 ± 5.53 ng/mg tissue weight (t.w. treatment compared to control (264.56 ± 15.46 ng/mg t.w.. R-PIA inhibition (0.01 µM = 141.97 ± 15.79 vs control = 244.77 ± 13.79 ng/mg t.w. of PRL release was blocked by 1 µM cyclopentyltheophylline, a specific A1 receptor antagonist (1 µM = 212.360 ± 26.560 ng/mg t.w., whereas cyclopentyltheophylline alone (0.01, 0.1, 1 µM had no effect. R-PIA (0.001, 0.01, 0.1, 1 µM produced inhibition of PRL secretion stimulated by both phospholipase C (0.5 IU/mL; 977.44 ± 76.17 ng/mg t.w. and dibutyryl cAMP (1 mM; 415.93 ± 37.66 ng/mg t.w. with nadir established at the dose of 0.1 µM (225.55 ± 71.42 and 201.9 ± 19.08 ng/mg t.w., respectively. Similarly, R-PIA (0.01 µM decreased (242.00 ± 24.00 ng/mg t.w. the PRL secretion stimulated by cholera toxin (0.5 mg/mL; 1050.00 ± 70.00 ng/mg t.w.. In contrast, R-PIA had no effect (468.00 ± 34.00 ng/mg t.w. on PRL secretion stimulation by pertussis toxin (0.5 mg/mL; 430.00 ± 26.00 ng/mg t.w.. These results suggest that inhibition of PRL secretion after A1 receptor activation by R-PIA is mediated by a Gi protein-dependent mechanism.

  16. Development of radioimmunoassay for prolactin binding protein

    Energy Technology Data Exchange (ETDEWEB)

    Raikar, R.S.; Sheth, A.R. (Institute for Research in Reproduction, Bombay (India))

    1982-01-01

    Using a homogenous prolactin binding protein (PBP) preparations from rat seminal vesicle secretion, a sensitive and specific radioimmunoassay (RIA) for PBP has been developed. The assay was highly specific and showed no cross-reaction with other protein hormones from various species. The antiserum had an affinity constant (Ka) of 2.66 x 10/sup 10/ M/sup -1/. The assay sensitivity was in the range of 0.5-1.0 ng of pure PBP per assay tube and the intra- and inter-assay coefficients of variations were 6-8% and 12-14.5% respectively. The overall recovery of PBP to the rat seminal vesicle secretion was 96.8%. Using this RIA, PBP levels in various biological fluids and reproductive tissues were measured. Azoospermic human semen contained significantly higher levels of PBP than normospermic semen. The seminal vesicle of rat exhibited the highest concentration of PBP. Administration of antiserum to PBP to mature male rats resulted in a significant reduction in the weight of ventral prostrate and serum prolactin levels were significantly elevated in these animals suggesting that the antibody raised against the PBP was capable of blocking prolactin receptors.

  17. 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.

  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. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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...

  4. 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.

  5. Identification of the reptilian prolactin and its receptor cDNAs in the leopard gecko, Eublepharis macularius.

    Science.gov (United States)

    Kato, Keisuke; Ikemoto, Tadahiro; Park, Min Kyun

    2005-02-14

    In spite of their physiological significance, there is no available information about the nucleotide sequences of prolactin (PRL) and its receptor in reptilian species. In order to fill this gap, PRL and its receptor cDNAs were identified in a reptilian species, the leopard gecko Eublepharis macularius. The deduced leopard gecko PRL polypeptide showed high identities with the corresponding polypeptides of other reptiles. The leopard gecko PRL receptor (PRLR) was estimated to have tandem repeated regions in its extracellular domain, which had been originally found in avian PRLR. Molecular phylogenetic analysis suggests that these tandem repeated regions were generated by the duplication of the extracellular region in the latest common ancestor among reptiles and birds. In addition, tissue distributions of PRL and PRLR in the leopard gecko were examined by the reverse transcription-polymerase chain reaction (RT-PCR). PRLR mRNA was detected in all tissues examined and highly expressed in the whole brain, pituitary, intestine, kidney, ovary, oviduct and testis. Whereas, PRL mRNA was expressed in the whole brain, pituitary, ovary and testis. The co-expressions of PRL and its receptor in some extrapituitary organs suggest that PRL acts as an autocrine/paracrine factor in such organs of the leopard gecko.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Wild-type offspring of heterozygous prolactin receptor-null female mice have maladaptive β-cell responses during pregnancy.

    Science.gov (United States)

    Huang, Carol

    2013-03-01

    Abstract  β-Cell mass increases during pregnancy in adaptation to the insulin resistance of pregnancy. This increase is accompanied by an increase in β-cell proliferation, a process that requires intact prolactin receptor (Prlr) signalling. Previously, it was found that during pregnancy, heterozygous prolactin receptor-null (Prlr(+/-)) mice had lower number of β-cells, lower serum insulin and higher blood glucose levels than wild-type (Prlr(+/+)) mice. An unexpected observation was that the glucose homeostasis of the experimental mouse depends on the genotype of her mother, such that within the Prlr(+/+) group, the Prlr(+/+) offspring derived from Prlr(+/+) mothers (Prlr(+/+(+/+))) had higher β-cell mass and lower blood glucose than those derived from Prlr(+/-) mothers (Prlr(+/+(+/-))). Pathways that are known to regulate β-cell proliferation during pregnancy include insulin receptor substrate-2, Akt, menin, the serotonin synthetic enzyme tryptophan hydroxylase-1, Forkhead box M1 and Forkhead box D3. The aim of the present study was to determine whether dysregulation in these signalling molecules in the islets could explain the maternal effect on the phenotype of the offspring. It was found that the pregnancy-induced increases in insulin receptor substrate-2 and Akt expression in the islets were attenuated in the Prlr(+/+(+/-)) mice in comparison to the Prlr(+/+(+/+)) mice. The expression of Forkhead box D3, which plays a permissive role for β-cell proliferation during pregnancy, was also lower in the Prlr(+/+(+/-)) mice. In contrast, the pregnancy-induced increases in phospho-Jak2, tryptophan hydroxylase-1 and FoxM1, as well as the pregnancy-associated reduction in menin expression, were comparable between the two groups. There was also no difference in expression levels of genes that regulate insulin synthesis and secretion (i.e. glucose transporter 2, glucokinase and pancreatic and duodenal homeobox-1) between these two groups. Taken together, these

  13. Tachykinin NK₁ receptor antagonist co-administration attenuates opioid withdrawal-mediated spinal microglia and astrocyte activation.

    Science.gov (United States)

    Tumati, Suneeta; Largent-Milnes, Tally M; Keresztes, Attila I; Yamamoto, Takashi; Vanderah, Todd W; Roeske, William R; Hruby, Victor J; Varga, Eva V

    2012-06-05

    Prolonged morphine treatment increases pain sensitivity in many patients. Enhanced spinal Substance P release is one of the adaptive changes associated with sustained opioid exposure. In addition to pain transmitting second order neurons, spinal microglia and astrocytes also express functionally active Tachykinin NK₁ (Substance P) receptors. In the present work we investigated the role of glial Tachykinin NK₁ receptors in morphine withdrawal-mediated spinal microglia and astrocyte activation. Our data indicate that intrathecal co-administration (6 days, twice daily) of a selective Tachykinin NK₁ receptor antagonist (N-acetyl-L-tryptophan 3,5-bis(trifluoromethyl)benzylester (L-732,138; 20 μg/injection)) attenuates spinal microglia and astrocyte marker and pro-inflammatory mediator immunoreactivity as well as hyperalgesia in withdrawn rats. Furthermore, covalent linkage of the opioid agonist with a Tachykinin NK₁ antagonist pharmacophore yielded a bivalent compound that did not augment spinal microglia or astrocyte marker or pro-inflammatory mediator immunoreactivity and did not cause paradoxical pain sensitization upon drug withdrawal. Thus, bivalent opioid/Tachykinin NK₁ receptor antagonists may provide a novel paradigm for long-term pain management.

  14. 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.

  15. 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.

  16. The Beckman DxI 800 prolactin assay demonstrates superior specificity for monomeric prolactin.

    LENUS (Irish Health Repository)

    Byrne, Brendan

    2010-02-01

    Commercially available prolactin immunoassays detect macroprolactin to variable degrees. Best practice requires laboratories to assess the cross-reactivity of their prolactin assay with macroprolactin, and where appropriate, introduce a screen for the presence of macroprolactin. Our policy has been to reanalyse hyperprolactinaemic samples following polyethylene glycol (PEG) precipitation and to report the resultant value as the monomeric prolactin content of the sample. The goal of this study was to determine the need to continue PEG precipitation when prolactin measurements with the Wallac AutoDELFIA were replaced by the Beckman DxI 800.

  17. 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.

  18. Prolactin receptor, growth hormone receptor, and putative somatolactin receptor in Mozambique tilapia: tissue specific expression and differential regulation by salinity and fasting.

    Science.gov (United States)

    Pierce, A L; Fox, B K; Davis, L K; Visitacion, N; Kitahashi, T; Hirano, T; Grau, E G

    2007-01-01

    In fish, pituitary growth hormone family peptide hormones (growth hormone, GH; prolactin, PRL; somatolactin, SL) regulate essential physiological functions including osmoregulation, growth, and metabolism. Teleost GH family hormones have both differential and overlapping effects, which are mediated by plasma membrane receptors. A PRL receptor (PRLR) and two putative GH receptors (GHR1 and GHR2) have been identified in several teleost species. Recent phylogenetic analyses and binding studies suggest that GHR1 is a receptor for SL. However, no studies have compared the tissue distribution and physiological regulation of all three receptors. We sequenced GHR2 from the liver of the Mozambique tilapia (Oreochromis mossambicus), developed quantitative real-time PCR assays for the three receptors, and assessed their tissue distribution and regulation by salinity and fasting. PRLR was highly expressed in the gill, kidney, and intestine, consistent with the osmoregulatory functions of PRL. PRLR expression was very low in the liver. GHR2 was most highly expressed in the muscle, followed by heart, testis, and liver, consistent with this being a GH receptor with functions in growth and metabolism. GHR1 was most highly expressed in fat, liver, and muscle, suggesting a metabolic function. GHR1 expression was also high in skin, consistent with a function of SL in chromatophore regulation. These findings support the hypothesis that GHR1 is a receptor for SL. In a comparison of freshwater (FW)- and seawater (SW)-adapted tilapia, plasma PRL was strongly elevated in FW, whereas plasma GH was slightly elevated in SW. PRLR expression was reduced in the gill in SW, consistent with PRL's function in freshwater adaptation. GHR2 was elevated in the kidney in FW, and correlated negatively with plasma GH, whereas GHR1 was elevated in the gill in SW. Plasma IGF-I, but not GH, was reduced by 4 weeks of fasting. Transcript levels of GHR1 and GHR2 were elevated by fasting in the muscle. However

  19. The WSXWS motif in cytokine receptors is a molecular switch involved in receptor activation

    DEFF Research Database (Denmark)

    Dagil, Robert; Knudsen, Maiken J.; Olsen, Johan Gotthardt

    2012-01-01

    The prolactin receptor (PRLR) is activated by binding of prolactin in a 2:1 complex, but the activation mechanism is poorly understood. PRLR has a conserved WSXWS motif generic to cytokine class I receptors. We have determined the nuclear magnetic resonance solution structure of the membrane...

  20. 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.

  1. 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...

  2. 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.

  3. Prolactin blood test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003718.htm Prolactin blood test To use the sharing features on this page, ... test measures the amount of prolactin in the blood. How the Test is Performed A blood sample is needed . How ...

  4. 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

  5. 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...

  6. 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

  7. Paradoxical effects of oxytocin and vasopressin on basal prolactin secretion and the estrogen-induced prolactin surge

    International Nuclear Information System (INIS)

    Mai, Leemin; Pan, Jenntser

    1990-01-01

    The roles of oxytocin (OT) and vasopressin (AVP) on both basal and estrogen-induced prolactin (PRL) secretion were examined. Adult female Sprague-Dawley rats that were ovariectomized for 3 weeks and received estrogen treatment for 1 week were used. Intravenous administration of hormones and serial blood sampling were accomplished through indwelling intraatrial catheters which were implanted two days before. Plasma PRL levels were measured by radioimmunoassay. Oxytocin at a dose of 20 μg/rat stimulated a moderate PRL release in the morning and lower doses were without effect. Vasopressin was most effective at a dose of 5 μg/rat in stimulating PRL release, while consecutive injections of higher doses were less effective. In contrast, TRH, ranging from 1 to 8 μg/rat, induced a dose-dependent increases in PRL secretion. Using the effective dosages determined from the morning studies, repeated injections of either OT, AVP or their specific antagonists MPOMeOVT were given hourly between 1300 to 1800h and blood samples were obtained hourly from 1100 to 1900h. It was found that either OT or AVP significantly reduced the afternoon PRL surge, while their antagonists were not as effective

  8. 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

  9. 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.

  10. Dopamine inhibits maitotoxin-stimulated pituitary 45Ca2+ efflux and prolactin release

    International Nuclear Information System (INIS)

    Login, I.S.; Judd, A.M.; MacLeod, R.M.

    1986-01-01

    The authors examined the hypothesis that dopaminergic inhibition of prolactin release is coupled to modulation of cellular calcium flux. Dispersed female rat pituitary cells were prelabeled in 45 Ca 2+ and perifused to determine simultaneously fractional calcium efflux and prolactin release, as stimulated by maitotoxin, a calcium channel activator. The integrated response of each parameter to 5 ng/ml maitotoxin was obtained in individual perifusion columns in the absence or presence of various concentrations of dopamine. Maitotoxin-stimulated calcium efflux was suppressed by dopamine concentrations of 0.01 μM and greater and achieved a maximal effect at ∼0.1 μM, at which calcium efflux was reduced by 50%. Maitotoxin-stimulated prolactin release was inhibited by 0.03 μM dopamine and greater concentrations, and at a concentration of ∼10.0 μM dopamine the effect became maximal at ∼85% suppression. Haloperidol (0.1 μM) blocked the effects of 0.1 μM dopamine on both parameters. Simultaneous suppression of maitotoxin-stimulated calcium efflux and prolactin release by concentrations of dopamine within the nonomolar range suggests that dopamine receptor activation is negatively coupled to modulation of calcium flux in the physiological regulation of prolactin secretion

  11. Understanding the Inguinal Sinus in Sheep (Ovis aries—Morphology, Secretion, and Expression of Progesterone, Estrogens, and Prolactin Receptors

    Directory of Open Access Journals (Sweden)

    Graça Alexandre-Pires

    2017-07-01

    Full Text Available Post-parturient behavior of mammalian females is essential for early parent–offspring contact. After delivery, lambs need to ingest colostrum for obtaining the related immunological protection, and early interactions between the mother and the lamb are crucial. Despite visual and auditory cues, olfactory cues are decisive in lamb orientation to the mammary gland. In sheep, the inguinal sinus is located bilaterally near the mammary gland as a skin pouch (IGS that presents a gland that secretes a strong-smelling wax. Sheep IGS gland functions have many aspects under evaluation. The objective of the present study was to evaluate sheep IGS gland functional aspects and mRNA transcription and the protein expression of several hormone receptors, such as progesterone receptor (PGR, estrogen receptor 1 (ESR1, and 2 (ESR2 and prolactin receptor (PRLR present. In addition, another aim was to achieve information about IGS ultrastructure and chemical compounds produced in this gland. All hormone receptors evaluated show expression in IGS during the estrous cycle (follicular/luteal phases, pregnancy, and the post-partum period. IGS secretion is rich in triterpenoids that totally differ from the surrounding skin. They might be essential substances for the development of an olfactory preference of newborns to their mothers.

  12. 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.

  13. Shifting physician prescribing to a preferred histamine-2-receptor antagonist. Effects of a multifactorial intervention in a mixed-model health maintenance organization.

    Science.gov (United States)

    Brufsky, J W; Ross-Degnan, D; Calabrese, D; Gao, X; Soumerai, S B

    1998-03-01

    This study was undertaken to determine whether a program of education, therapeutic reevaluation of eligible patients, and performance feedback could shift prescribing to cimetidine from other histamine-2 receptor antagonists, which commonly are used in the management of ulcers and reflux, and reduce costs without increasing rates of ulcer-related hospital admissions. This study used an interrupted monthly time series with comparison series in a large mixed-model health maintenance organization. Physicians employed in health centers (staff model) and physicians in independent medical groups contracting to provide health maintenance organization services (group model) participated. The comparative percentage prescribed of specific histamine-2 receptor antagonists (market share), total histamine-2 receptor antagonist prescribing, cost per histamine-2 receptor antagonist prescription, and the rate of hospitalization for gastrointestinal illness were assessed. In the staff model, therapeutic reevaluation resulted in a sudden increase in market share of the preferred histamine-2 receptor antagonist cimetidine (+53.8%) and a sudden decrease in ranitidine (-44.7%) and famotidine (-4.8%); subsequently, cimetidine market share grew by 1.1% per month. In the group model, therapeutic reevaluation resulted in increased cimetidine market share (+9.7%) and decreased prescribing of other histamine-2 receptor antagonists (ranitidine -11.6%; famotidine -1.2%). Performance feedback did not result in further changes in prescribing in either setting. Use of omeprazole, an expensive alternative, essentially was unchanged by the interventions, as were overall histamine-2 receptor antagonist prescribing and hospital admissions for gastrointestinal illnesses. This intervention, which cost approximately $60,000 to implement, resulted in estimated annual savings in histamine-2 receptor antagonist expenditures of $1.06 million. Annual savings in histamine-2 receptor antagonist expenditures

  14. 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

  15. 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.

  16. Casopitant: a novel NK1-receptor antagonist in the prevention of chemotherapy-induced nausea and vomiting

    Directory of Open Access Journals (Sweden)

    Christina Ruhlmann

    2009-05-01

    Full Text Available Christina Ruhlmann, Jørn HerrstedtOdense University Hospital, Department of Oncology, Odense, DenmarkAbstract: Chemotherapy-induced nausea and vomiting (CINV are among the most feared and distressing symptoms experienced by patients with cancer. The knowledge of the pathogenesis and neuropharmacology of CINV has expanded enormously over the last decades, the most significant discoveries being the role of 5-hydroxytryptamine (5-HT3- and neurokinin (NK1 receptors in the emetic reflex arch. This has led to the development of two new classes of antiemetics acting as highly selective antagonists at one of these receptors. These drugs have had a huge impact in the protection from chemotherapy-induced vomiting, whereas the effect on nausea seems to be limited. The first NK1 receptor antagonist, aprepitant, became clinically available in 2003, and casopitant, the second in this class of antiemetics, has now completed phase III trials. This review delineates the properties and clinical use of casopitant in the prevention of CINV.Keywords: casopitant, GW679769, NK1 receptor antagonist, chemotherapy, emesis

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. Effects of short- and long-term risperidone treatment on prolactin levels in children with autism.

    Science.gov (United States)

    Anderson, George M; Scahill, Lawrence; McCracken, James T; McDougle, Christopher J; Aman, Michael G; Tierney, Elaine; Arnold, L Eugene; Martin, Andrés; Katsovich, Liliya; Posey, David J; Shah, Bhavik; Vitiello, Benedetto

    2007-02-15

    The effects of short- and long-term risperidone treatment on serum prolactin were assessed in children and adolescents with autism. Patients with autism (N = 101, 5-17 years of age) were randomized to an 8-week trial of risperidone or placebo and 63 then took part in a 4-month open-label follow-up phase. Serum samples were obtained at Baseline and Week-8 (N = 78), and at 6-month (N = 43) and 22-month (N = 30) follow-up. Serum prolactin was determined by immunoradiometric assay; dopamine type-2 receptor (DRD2) polymorphisms were genotyped. Baseline prolactin levels were similar in the risperidone (N = 42) and placebo (N = 36) groups (9.3 +/- 7.5 and 9.3 +/- 7.6 ng/ml, respectively). After 8 weeks of risperidone, prolactin increased to 39.0 +/- 19.2 ng/ml, compared with 10.1 +/- 8.8 ng/ml for placebo (p autism. Although risperidone-induced increases tended to diminish with time, further research on the consequences of long-term prolactin elevations in children and adolescents is needed.

  2. Non-peptidic antagonists of the CGRP receptor, BIBN4096BS and MK-0974, interact with the calcitonin receptor-like receptor via methionine-42 and RAMP1 via tryptophan-74.

    Science.gov (United States)

    Miller, Philip S; Barwell, James; Poyner, David R; Wigglesworth, Mark J; Garland, Stephen L; Donnelly, Dan

    2010-01-01

    The receptor for calcitonin gene-related peptide (CGRP) has been the target for the development of novel small molecule antagonists for the treatment of migraine. Two such antagonists, BIBN4096BS and MK-0974, have shown great promise in clinical trials and hence a deeper understanding of the mechanism of their interaction with the receptor is now required. The structure of the CGRP receptor is unusual since it is comprised of a hetero-oligomeric complex between the calcitonin receptor-like receptor (CRL) and an accessory protein (RAMP1). Both the CLR and RAMP1 components have extracellular domains which interact with each other and together form part of the peptide-binding site. It seems likely that the antagonist binding site will also be located on the extracellular domains and indeed Trp-74 of RAMP1 has been shown to form part of the binding site for BIBN4096BS. However, despite a chimeric study demonstrating the role of the N-terminal domain of CLR in antagonist binding, no specific residues have been identified. Here we carry out a mutagenic screen of the extreme N-terminal domain of CLR (residues 23-63) and identify a mutant, Met-42-Ala, which displays 48-fold lower affinity for BIBN4096BS and almost 900-fold lower affinity for MK-0974. In addition, we confirm that the Trp-74-Lys mutation at human RAMP1 reduces BIBN4096BS affinity by over 300-fold and show for the first time a similar effect for MK-0974 affinity. The data suggest that the non-peptide antagonists occupy a binding site close to the interface of the N-terminal domains of CLR and RAMP1. Copyright 2009 Elsevier Inc. All rights reserved.

  3. 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

  4. 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.

  5. (−) 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

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 3D-QSAR comparative molecular field analysis on opioid receptor antagonists: pooling data from different studies.

    Science.gov (United States)

    Peng, Youyi; Keenan, Susan M; Zhang, Qiang; Kholodovych, Vladyslav; Welsh, William J

    2005-03-10

    Three-dimensional quantitative structure-activity relationship (3D-QSAR) models were constructed using comparative molecular field analysis (CoMFA) on a series of opioid receptor antagonists. To obtain statistically significant and robust CoMFA models, a sizable data set of naltrindole and naltrexone analogues was assembled by pooling biological and structural data from independent studies. A process of "leave one data set out", similar to the traditional "leave one out" cross-validation procedure employed in partial least squares (PLS) analysis, was utilized to study the feasibility of pooling data in the present case. These studies indicate that our approach yields statistically significant and highly predictive CoMFA models from the pooled data set of delta, mu, and kappa opioid receptor antagonists. All models showed excellent internal predictability and self-consistency: q(2) = 0.69/r(2) = 0.91 (delta), q(2) = 0.67/r(2) = 0.92 (mu), and q(2) = 0.60/r(2) = 0.96 (kappa). The CoMFA models were further validated using two separate test sets: one test set was selected randomly from the pooled data set, while the other test set was retrieved from other published sources. The overall excellent agreement between CoMFA-predicted and experimental binding affinities for a structurally diverse array of ligands across all three opioid receptor subtypes gives testimony to the superb predictive power of these models. CoMFA field analysis demonstrated that the variations in binding affinity of opioid antagonists are dominated by steric rather than electrostatic interactions with the three opioid receptor binding sites. The CoMFA steric-electrostatic contour maps corresponding to the delta, mu, and kappa opioid receptor subtypes reflected the characteristic similarities and differences in the familiar "message-address" concept of opioid receptor ligands. Structural modifications to increase selectivity for the delta over mu and kappa opioid receptors have been predicted on the

  11. 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.

  12. The Antidepressant 5-HT2A Receptor Antagonists Pizotifen and Cyproheptadine Inhibit Serotonin-Enhanced Platelet Function

    Science.gov (United States)

    Lin, Olivia A.; Karim, Zubair A.; Vemana, Hari Priya; Espinosa, Enma V. P.; Khasawneh, Fadi T.

    2014-01-01

    There is considerable interest in defining new agents or targets for antithrombotic purposes. The 5-HT2A receptor is a G-protein coupled receptor (GPCR) expressed on many cell types, and a known therapeutic target for many disease states. This serotonin receptor is also known to regulate platelet function. Thus, in our FDA-approved drug repurposing efforts, we investigated the antiplatelet activity of cyproheptadine and pizotifen, two antidepressant 5-HT2A Receptor antagonists. Our results revealed that cyproheptadine and pizotifen reversed serotonin-enhanced ADP-induced platelet aggregation in vitro and ex vivo. And the inhibitory effects of these two agents were found to be similar to that of EMD 281014, a 5-HT2A Receptor antagonist under development. In separate experiments, our studies revealed that these 5-HT2A receptor antagonists have the capacity to reduce serotonin-enhanced ADP-induced elevation in intracellular calcium levels and tyrosine phosphorylation. Using flow cytometry, we also observed that cyproheptadine, pizotifen, and EMD 281014 inhibited serotonin-enhanced ADP-induced phosphatidylserine (PS) exposure, P-selectin expression, and glycoprotein IIb-IIIa activation. Furthermore, using a carotid artery thrombosis model, these agents prolonged the time for thrombotic occlusion in mice in vivo. Finally, the tail-bleeding time was investigated to assess the effect of cyproheptadine and pizotifen on hemostasis. Our findings indicated prolonged bleeding time in both cyproheptadine- and pizotifen-treated mice. Notably, the increases in occlusion and bleeding times associated with these two agents were comparable to that of EMD 281014, and to clopidogrel, a commonly used antiplatelet drug, again, in a fashion comparable to clopidogrel and EMD 281014. Collectively, our data indicate that the antidepressant 5-HT2A antagonists, cyproheptadine and pizotifen do exert antiplatelet and thromboprotective effects, but similar to clopidogrel and EMD 281014, their

  13. Agonist and antagonist actions of antipsychotic agents at 5-HT1A receptors: a [35S]GTPgammaS binding study.

    Science.gov (United States)

    Newman-Tancredi, A; Gavaudan, S; Conte, C; Chaput, C; Touzard, M; Verrièle, L; Audinot, V; Millan, M J

    1998-08-21

    Recombinant human (h) 5-HT1A receptor-mediated G-protein activation was characterised in membranes of transfected Chinese hamster ovary (CHO) cells by use of guanosine-5'-O-(3-[35S]thio)-triphosphate ([35S]GTPgammaS binding). The potency and efficacy of 21 5-HT receptor agonists and antagonists was determined. The agonists, 5-CT (carboxamidotryptamine) and flesinoxan displayed high affinity (subnanomolar Ki values) and high efficacy (Emax > 90%, relative to 5-HT = 100%). In contrast, ipsapirone, zalospirone and buspirone displayed partial agonist activity. EC50s for agonist stimulation of [35S]GTPgammaS binding correlated well with Ki values from competition binding (r = +0.99). Among the compounds tested for antagonist activity, methiothepin and (+)butaclamol exhibited 'inverse agonist' behaviour, inhibiting basal [35S]GTPgammaS binding. The actions of 17 antipsychotic agents were investigated. Clozapine and several putatively 'atypical' antipsychotic agents, including ziprasidone, quetiapine and tiospirone, exhibited partial agonist activity and marked affinity at h5-HT1A receptors, similar to their affinity at hD2 dopamine receptors. In contrast, risperidone and sertindole displayed low affinity at h5-HT1A receptors and behaved as 'neutral' antagonists, inhibiting 5-HT-stimulated [35S]GTPgammaS binding. Likewise the 'typical' neuroleptics, haloperidol, pimozide, raclopride and chlorpromazine exhibited relatively low affinity and 'neutral' antagonist activity at h5-HT1A receptors with Ki values which correlated with their respective Kb values. The present data show that (i) [35S]GTPgammaS binding is an effective method to evaluate the efficacy and potency of agonists and antagonists at recombinant human 5-HT1A receptors. (ii) Like clozapine, several putatively 'atypical' antipsychotic drugs display balanced serotonin h5-HT1A/dopamine hD2 receptor affinity and partial agonist activity at h5-HT1A receptors. (iii) Several 'typical' and some putatively 'atypical

  14. 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...

  15. ``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

  16. 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.

  17. Obtention of antibodies anti prolactin from human prolactin of national production

    International Nuclear Information System (INIS)

    Caso, R.; Mosquera, M.; Perez, E.; Amanz, C.

    1996-01-01

    In this work was studied the use of the the Prolactin hormone as immuno gen, which is obtained in Cuba by the pharmaceutical institute Mario Munoz, to produce the antibody antiprolactin. Was made the validation of obtained antibody (tritatium, specificity and affinity) The produced antibody had necessary quality to be use as a component of the Kits-RIA Prolactin

  18. 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.

  19. Serum prolactin level in patients taking olanzapine

    Directory of Open Access Journals (Sweden)

    Diganta Das

    2015-01-01

    Full Text Available Introduction: Olanzapine is a commonly used antipsychotic. Prolactin elevation is a common adverse effect of anstipsychotics, and serum prolactin elevation is seen in about 30% patients treated with olanzapine. There are confounding results about dose dependency of olanzapine and prolactin elevation, and also the duration of treatment. Method: Fifty six patients, 36 male and 20 female, who were taking olanzapine for any condition for more than a month at a constant dose were enrolled in the study. Patients’ age, weight, body mass index (BMI, serum prolactin levels, and some biochemical values were recorded. Patients were taken from the review outpatient department (OPD after due consent. Results: Five each in male and female groups showed elevation of serum prolactin (estimated to be high if >20 ng/dl for males, and >25 ng/dl for females. In females, the elevation was found at lesser dose of olanzapine (13 mg/day, in males 18 mg/day and early in the treatment (2.4 months vs. 9.7 months in males. Males tended to show raised prolactin with higher doses of olanzapine (mean 18 mg/day. Females (26.31% also showed higher prevalence of prolactin elevation compared to males (13.51%. No other parameter was found to modify the prolactin levels. Conclusion: Olanzapine causes elevation of serum prolactin, though lesser degree than some other antipsychotics. Females are more prone to have raised serum prolactin with olanzapine compared to males. However, the elevation seems to be transient. Higher doses of olanzapine tend to cause elevation of serum prolactin. Serum prolactin estimation in patients taking olanzapine may be undertaken to maintain quality life, particularly in females.

  20. 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.

  1. 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.

  2. 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

  3. Differential effects of the new glucocorticoid receptor antagonist ORG 34517 and RU486 (mifepristone) on glucocorticoid receptor nuclear translocation in the AtT20 cell line.

    Science.gov (United States)

    Peeters, B W M M; Ruigt, G S F; Craighead, M; Kitchener, P

    2008-12-01

    Glucocorticoid agonists bind to cytoplasmic glucocorticoid receptors (GRs) and subsequently translocate as an agonist-GR complex into the nucleus. In the nucleus the complex regulates the transcription of target genes. A number of GR antagonists (RU486, progesterone, RU40555) have also been shown to induce receptor translocation. These compounds should be regarded as partial agonists. For the nonselective progesterone receptor antagonists, RTI3021-012 and RTI3021-022, it was shown that GR antagonism is possible without the induction of GR translocation. In the present studies, the new GR antagonist, ORG 34517, was investigated for its potential to induce GR translocation and to antagonize corticosterone-induced GR translocation in the AtT20 (mouse pituitary) cell line. ORG 34517 was compared to RU486. In contrast to RU486, ORG 34517 (at doses up to 3 x 10(-7) M) did not induce GR translocation, but was able to block corticosterone (3 x 10(-8) M) induced GR translocation. ORG 34517 can be regarded as a true competitive GR antagonist without partial agonistic activities.

  4. CGRP receptors mediating CGRP-, adrenomedullin- and amylin-induced relaxation in porcine coronary arteries. Characterization with 'Compound 1' (WO98/11128), a non-peptide antagonist

    DEFF Research Database (Denmark)

    Hasbak, P; Sams, A; Schifter, S

    2001-01-01

    . The partial porcine mRNA sequences shared 82 - 92% nucleotide identity with human sequences. 3. The human peptides alphaCGRP, betaCGRP, AM and amylin induced relaxation with pEC(50) values of 8.1, 8.1, 6.7 and 6.1 M respectively. 4. The antagonistic properties of a novel non-peptide CGRP antagonist 'Compound...... 1' (WO98/11128), betaCGRP(8 - 37) and the proposed AM receptor antagonist AM(22 - 52) were compared to the well-known CGRP(1) receptor antagonist alphaCGRP(8 - 37). 5. The alphaCGRP(8 - 37) and betaCGRP(8 - 37) induced concentration-dependent (10(-7) - 10(-5) M) rightward shift of both the alpha......(-6) M) had no significant antagonistic effect. 7. In conclusion, the building blocks forming CGRP and AM receptors were present in the porcine LAD, whereas those of the amylin receptor were not. alphaCGRP, betaCGRP, AM and amylin mediated vasorelaxation via the CGRP receptors. No functional response...

  5. 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

  6. 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;

  7. 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.

  8. Clinical indications of prolactin radioimmunoassay

    International Nuclear Information System (INIS)

    Lengyel, A.M.J.; Vieira, J.G.H.; Zanella, M.R.; Zampieri, M.; Chacra, A.R.

    1980-01-01

    Is a review is presented of the main clinical uses of prolactin measurements, including the galactorrhea-amenorrhea syndrome, an experiment employing the prolactin radioimmunoassay is related. (Author) [pt

  9. 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.

  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. 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

  12. 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...

  13. 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.

  14. Prolactin release, oestrogens and proliferation of prolactin-secreting cells in the anterior pituitary gland of adult male rats.

    Science.gov (United States)

    Pérez, R L; Machiavelli, G A; Romano, M I; Burdman, J A

    1986-03-01

    Relationships among the release of prolactin, the effect of oestrogens and the proliferation of prolactin-secreting cells were studied under several experimental conditions. Administration of sulpiride or oestradiol released prolactin and stimulated cell proliferation in the anterior pituitary gland of adult male rats. Clomiphene completely abolished the rise in cell proliferation, but did not interfere with the sulpiride-induced release of prolactin. Treatment with oestradiol plus sulpiride significantly increased serum prolactin concentrations and the mitotic index compared with the sum of the stimulation produced by both drugs separately. Bromocriptine abolished the stimulatory effect of oestradiol on the serum prolactin concentration and on cell proliferation. In oestradiol- and/or sulpiride-treated rats, 80% of the cells in mitoses were lactotrophs. The remaining 20% did not stain with antisera against any of the pituitary hormones. The number of prolactin-secreting cells in the anterior pituitary gland significantly increased after the administration of oestradiol or sulpiride. The results demonstrate that treatment with sulpiride and/or oestradiol increases the proliferation and the number of lactotrophs in the anterior pituitary gland of the rat.

  15. 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.

  16. The effect of the Taq1A variant in the dopamine D2 receptor gene and common CYP2D6 alleles on prolactin levels in risperidone-treated boys

    NARCIS (Netherlands)

    Roke, Y.; Harten, P.N. van; Franke, B.; Galesloot, T.E.; Boot, A.M.; Buitelaar, J.K.

    2013-01-01

    OBJECTIVE: To investigate the effect of the Taq1A variant in the Dopamine D2 receptor gene (DRD2) and common functional genetic variants in the cytochrome P450 2D6 gene (CYP2D6) on prolactin levels in risperidone-treated boys with autism spectrum disorders and disruptive behavior disorders. METHODS:

  17. The effect of the Taq1A variant in the dopamine D-2 receptor gene and common CYP2D6 alleles on prolactin levels in risperidone-treated boys

    NARCIS (Netherlands)

    Roke, Yvette; van Harten, Peter N.; Franke, Barbara; Galesloot, Tessel E.; Boot, Annemieke M.; Buitelaar, Jan K.

    Objective To investigate the effect of the Taq1A variant in the Dopamine D2 receptor gene (DRD2) and common functional genetic variants in the cytochrome P450 2D6 gene (CYP2D6) on prolactin levels in risperidone-treated boys with autism spectrum disorders and disruptive behavior disorders.Methods

  18. 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...

  19. 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 ...

  20. 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.

  1. 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

  2. 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...

  3. Prolactin and teleost ionocytes: new insights into cellular and molecular targets of prolactin in vertebrate epithelia

    Science.gov (United States)

    Breves, Jason P.; McCormick, Stephen D.; Karlstrom, Rolf O.

    2014-01-01

    The peptide hormone prolactin is a functionally versatile hormone produced by the vertebrate pituitary. Comparative studies over the last six decades have revealed that a conserved function for prolactin across vertebrates is the regulation of ion and water transport in a variety of tissues including those responsible for whole-organism ion homeostasis. In teleost fishes, prolactin was identified as the “freshwater-adapting hormone”, promoting ion-conserving and water-secreting processes by acting on the gill, kidney, gut and urinary bladder. In mammals, prolactin is known to regulate renal, intestinal, mammary and amniotic epithelia, with dysfunction linked to hypogonadism, infertility, and metabolic disorders. Until recently, our understanding of the cellular mechanisms of prolactin action in fishes has been hampered by a paucity of molecular tools to define and study ionocytes, specialized cells that control active ion transport across branchial and epidermal epithelia. Here we review work in teleost models indicating that prolactin regulates ion balance through action on ion transporters, tight-junction proteins, and water channels in ionocytes, and discuss recent advances in our understanding of ionocyte function in the genetically and embryonically accessible zebrafish (Danio rerio). Given the high degree of evolutionary conservation in endocrine and osmoregulatory systems, these studies in teleost models are contributing novel mechanistic insight into how prolactin participates in the development, function, and dysfunction of osmoregulatory systems across the vertebrate lineage.

  4. Double dissociation of spike timing-dependent potentiation and depression by subunit-preferring NMDA receptor antagonists in mouse barrel cortex.

    Science.gov (United States)

    Banerjee, Abhishek; Meredith, Rhiannon M; Rodríguez-Moreno, Antonio; Mierau, Susanna B; Auberson, Yves P; Paulsen, Ole

    2009-12-01

    Spike timing-dependent plasticity (STDP) is a strong candidate for an N-methyl-D-aspartate (NMDA) receptor-dependent form of synaptic plasticity that could underlie the development of receptive field properties in sensory neocortices. Whilst induction of timing-dependent long-term potentiation (t-LTP) requires postsynaptic NMDA receptors, timing-dependent long-term depression (t-LTD) requires the activation of presynaptic NMDA receptors at layer 4-to-layer 2/3 synapses in barrel cortex. Here we investigated the developmental profile of t-LTD at layer 4-to-layer 2/3 synapses of mouse barrel cortex and studied their NMDA receptor subunit dependence. Timing-dependent LTD emerged in the first postnatal week, was present during the second week and disappeared in the adult, whereas t-LTP persisted in adulthood. An antagonist at GluN2C/D subunit-containing NMDA receptors blocked t-LTD but not t-LTP. Conversely, a GluN2A subunit-preferring antagonist blocked t-LTP but not t-LTD. The GluN2C/D subunit requirement for t-LTD appears to be synapse specific, as GluN2C/D antagonists did not block t-LTD at horizontal cross-columnar layer 2/3-to-layer 2/3 synapses, which was blocked by a GluN2B antagonist instead. These data demonstrate an NMDA receptor subunit-dependent double dissociation of t-LTD and t-LTP mechanisms at layer 4-to-layer 2/3 synapses, and suggest that t-LTD is mediated by distinct molecular mechanisms at different synapses on the same postsynaptic neuron.

  5. Reinforcing and neurochemical effects of cannabinoid CB1 receptor agonists, but not cocaine, are altered by an adenosine A2A receptor antagonist.

    Science.gov (United States)

    Justinová, Zuzana; Ferré, Sergi; Redhi, Godfrey H; Mascia, Paola; Stroik, Jessica; Quarta, Davide; Yasar, Sevil; Müller, Christa E; Franco, Rafael; Goldberg, Steven R

    2011-07-01

    Several recent studies suggest functional and molecular interactions between striatal adenosine A(2A) and cannabinoid CB(1) receptors. Here, we demonstrate that A(2A) receptors selectively modulate reinforcing effects of cannabinoids. We studied effects of A(2A) receptor blockade on the reinforcing effects of delta-9-tetrahydrocannabinol (THC) and the endogenous CB(1) receptor ligand anandamide under a fixed-ratio schedule of intravenous drug injection in squirrel monkeys. A low dose of the selective adenosine A(2A) receptor antagonist MSX-3 (1 mg/kg) caused downward shifts of THC and anandamide dose-response curves. In contrast, a higher dose of MSX-3 (3 mg/kg) shifted THC and anandamide dose-response curves to the left. MSX-3 did not modify cocaine or food pellet self-administration. Also, MSX-3 neither promoted reinstatement of extinguished drug-seeking behavior nor altered reinstatement of drug-seeking behavior by non-contingent priming injections of THC. Finally, using in vivo microdialysis in freely-moving rats, a behaviorally active dose of MSX-3 significantly counteracted THC-induced, but not cocaine-induced, increases in extracellular dopamine levels in the nucleus accumbens shell. The significant and selective results obtained with the lower dose of MSX-3 suggest that adenosine A(2A) antagonists acting preferentially at presynaptic A(2A) receptors might selectively reduce reinforcing effects of cannabinoids that lead to their abuse. However, the appearance of potentiating rather than suppressing effects on cannabinoid reinforcement at the higher dose of MSX-3 would likely preclude the use of such a compound as a medication for cannabis abuse. Adenosine A(2A) antagonists with more selectivity for presynaptic versus postsynaptic receptors could be potential medications for treatment of cannabis abuse. Addiction Biology © 2010 Society for the Study of Addiction. No claim to original US government works.

  6. 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...

  7. 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.

  8. Estrogen effects on angiotensin receptors are modulated by pituitary in female rats

    International Nuclear Information System (INIS)

    Douglas, J.G.

    1987-01-01

    The present studies were designed to test the hypothesis that changes in angiotensin II (ANG II) receptors might modulate the layered target tissue responsiveness accompanying estradiol administration. Estradiol was infused continuously in oophorectomized female rats. Aldosterone was also infused in control and experimental animals to avoid estrogen-induced changes in renin and ANG II. ANG II binding constants were determined in radioreceptor assays. Estradiol increased binding site concentration in adrenal glomerulosa by 76% and decreased binding sites of uterine myometrium and glomeruli by 45 and 24%, respectively. There was an accompanying increase in the affinity of ANG II binding to adrenal glomerulosa and uterine myometrium. Because estrogen is a potent stimulus of prolactin release from the pituitary of rodents, studies were also designed to test the hypothesis that prolactin may mediate some or all of the estrogen-induced effects observed. Hypophysectomy abolished estradiol stimulation of prolactin release and most ANG II receptor changes. Prolactin administration to pituitary intact rats was associated with a 50% increase in receptor density of adrenal glomerulosa simulating estradiol administration. However, the changes in glomeruli and uterine myometrium were opposite in that both tissues also increased receptor density, suggesting that prolactin was not the sole mediator of the estrogen-induced receptor changes. In conclusion, regulation of ANG II receptors in a number of diverse target tissues by estradiol is complex with contributions from estrogens and pituitary factors, which include but do not exclusively involve prolactin

  9. Identification of Glycyrrhiza as the rikkunshito constituent with the highest antagonistic potential on heterologously expressed 5HT3A receptors due to the action of flavonoids

    Directory of Open Access Journals (Sweden)

    Robin eHerbrechter

    2015-07-01

    Full Text Available The traditional Japanese phytomedicine rikkunshito is traditionally used for the treatment of gastrointestinal motility disorders, cachexia and nausea. These effects indicate 5-HT3 receptor antagonism, due to the involvement of these receptors in such pathophysiological processes. E.g. setrons, specific 5-HT3 receptor antagonists are the strongest antiemetics, developed so far. Therefore, the antagonistic effects of the eight rikkunshito constituents at heterologously expressed 5-HT3A receptors were analyzed using the two-electrode voltage-clamp technique. The results indicate that tinctures from Aurantii, Ginseng, Zingiberis, Atractylodis and Glycyrrhiza inhibited the 5-HT3A receptor response, whereas the tinctures of Poria cocos, Jujubae and Pinellia exhibited no effect. Surprisingly, the strongest antagonism was found for Glycyrrhiza, whereas the Zingiberis tincture, which is considered to be primarily responsible for the effect of rikkunshito, exhibited the weakest antagonist of 5-HT3A receptors. Rikkunshito contains various vanilloids, ginsenosides and flavonoids, a portion of which show an antagonistic effect on 5-HT3 receptors. A screening of the established ingredients of the active rikkunshito constituents and related substances lead to the identification of new antagonists within the class of flavonoids. The flavonoids (--liquiritigenin, glabridin and licochalcone A from Glycyrrhiza species were found to be the most effective inhibitors of the 5-HT-induced currents in the screening. The flavonoids (--liquiritigenin and hesperetin from Aurantii inhibited the receptor response in a non-competitive manner, whereas glabridin and licochalcone A exhibited a potential competitive antagonism. Furthermore, licochalcone A acts as a partial antagonist of 5-HT3A receptors. Thus, this study reveals new 5-HT3A receptor antagonists with the aid of increasing the comprehension of the complex effects of rikkunshito.

  10. 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.

  11. Vorapaxar: The Current Role and Future Directions of a Novel Protease-Activated Receptor Antagonist for Risk Reduction in Atherosclerotic Disease.

    Science.gov (United States)

    Gryka, Rebecca J; Buckley, Leo F; Anderson, Sarah M

    2017-03-01

    Despite the current standard of care, patients with cardiovascular disease remain at a high risk for recurrent events. Inhibition of thrombin-mediated platelet activation through protease-activated receptor-1 antagonism may provide reductions in atherosclerotic disease beyond those achievable with the current standard of care. Our primary objective is to evaluate the clinical literature regarding the role of vorapaxar (Zontivity™) in the reduction of cardiovascular events in patients with a history of myocardial infarction and peripheral artery disease. In particular, we focus on the potential future directions for protease-activating receptor antagonists in the treatment of a broad range of atherosclerotic diseases. A literature search of PubMed and EBSCO was conducted to identify randomized clinical trials from August 2005 to June 2016 using the search terms: 'vorapaxar', 'SCH 530348', 'protease-activated receptor-1 antagonist', and 'Zontivity™'. Bibliographies were searched and additional resources were obtained. Vorapaxar is a first-in-class, protease-activated receptor-1 antagonist. The Thrombin Receptor Antagonist for Clinical Event Reduction (TRACER) trial did not demonstrate a significant reduction in a broad primary composite endpoint. However, the Thrombin-Receptor Antagonist in Secondary Prevention of Atherothrombotic Ischemic Events (TRA 2°P-TIMI 50) trial examined a more traditional composite endpoint and found a significant benefit with vorapaxar. Vorapaxar significantly increased bleeding compared with standard care. Ongoing trials will help define the role of vorapaxar in patients with peripheral arterial disease, patients with diabetes mellitus, and other important subgroups. The use of multivariate modeling may enable the identification of subgroups with maximal benefit and minimal harm from vorapaxar. Vorapaxar provides clinicians with a novel mechanism of action to further reduce the burden of ischemic heart disease. Identification of

  12. 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.

  13. 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.

  14. 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.

  15. Sex differences in the relationship between prolactin levels and impaired processing speed in early psychosis.

    Science.gov (United States)

    Montalvo, Itziar; Nadal, Roser; Armario, Antonio; Gutiérrez-Zotes, Alfonso; Creus, Marta; Cabezas, Ángel; Solé, Montse; Algora, Maria José; Sánchez-Gistau, Vanessa; Vilella, Elisabet; Labad, Javier

    2018-06-01

    Hyperprolactinaemia is commonly observed in people with psychotic disorders due to D2 receptor blockade by antipsychotic drugs, although it may also exist in drug-naïve patients with first-episode psychosis. Recent studies suggest that hyperprolactinaemia may have a negative impact on cognitive function in people with early psychosis. We aimed to explore whether there are sex differences in the association between prolactin levels and cognitive performance in early psychosis patients. We studied 60 young patients with early psychosis (aged 18-35 years, 35% females) and a sex- and age-matched control group of 50 healthy subjects. Cognitive assessment was performed with the MATRICS Consensus Cognitive Battery. Prolactin, total cortisol, follicular-stimulating hormone, luteal hormone and sex steroids (testosterone in men, oestradiol and progesterone in women) were measured in plasma. Salivary cortisol was measured at different sampling times (awakening response, 10:00 and 23:00). Psychopathological status was assessed, and antipsychotic treatment was registered. Multiple linear regression analyses were used to explore the relationship between prolactin and cognitive tasks while adjusting for covariates. Prolactin levels were associated with impaired processing speed in men, and this association was independent of cortisol and testosterone. In women, prolactin levels were not associated with processing speed tasks, although we observed a negative effect of prolactin on verbal learning and spatial working memory in female healthy subjects. The male-dependent effect maintained its significance after adjusting for education status, antipsychotic treatment and negative symptoms. Our study demonstrates that the previously reported association between high prolactin levels and impaired cognitive processes in early psychosis is restricted to men.

  16. In vivo brain dopaminergic receptor site mapping using 75Se-labeled pergolide analogs: the effects of various dopamine receptor agonists and antagonists

    International Nuclear Information System (INIS)

    Weaver, A.

    1986-01-01

    Perogolide mesylate is a new synthetic ergoline derivative which is reported to possess agonistic activity at central dopamine receptor sites in the brain. The authors have synthesized a [ 75 Se]-radiolabeled pergolide mesylate derivative, [ 75 Se]-pergolide tartrate, which, after i.v. administration to mature male rats, showed a time course differentiation in the uptake of this radiolabeled compound in isolated peripheral and central (brain) tissues that are known to be rich in dopamine receptor sites. Further studies were conducted in which the animals were preexposed to the dopamine receptor agonist SKF-38393, as well as the dopamine receptor antagonists (+)-butaclamol, (-)-butaclamol, (+/-)-butaclamol and (-)-chloroethylnorapomorphine, to substantiate the specific peripheral and central localization patterns of [ 75 Se]-pergolide tartrate. Further investigations were also conducted in which the animals received an i.v. administration of N-isopropyl-l-123-p-iodoamphetamine ([ 123 I]-iodoamphetamine). However, [ 123 I]-iodoamphetamine did not demonstrate a specific affinity for any type of receptor site in the brain. These investigations further substantiated the fact that [ 75 Se]-pergolide tartrate does cross the blood-brain barrier is quickly localized at specific dopamine receptor sites in the intact rat brain and that this localization pattern can be affected by preexposure to different dopamine receptor agonists and antagonists. Therefore, these investigations provided further evidence that [ 75 Se]-pergolide tartrate and other radiolabeled ergoline analogs might be useful as brain dopamine receptor localization radiopharmaceuticals

  17. 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

  18. ATM Is Required for the Prolactin-Induced HSP90-Mediated Increase in Cellular Viability and Clonogenic Growth After DNA Damage.

    Science.gov (United States)

    Karayazi Atici, Ödül; Urbanska, Anna; Gopinathan, Sesha Gopal; Boutillon, Florence; Goffin, Vincent; Shemanko, Carrie S

    2018-02-01

    Prolactin (PRL) acts as a survival factor for breast cancer cells, but the PRL signaling pathway and the mechanism are unknown. Previously, we identified the master chaperone, heat shock protein 90 (HSP90) α, as a prolactin-Janus kinase 2 (JAK2)-signal transducer and activator of transcription 5 (STAT5) target gene involved in survival, and here we investigated the role of HSP90 in the mechanism of PRL-induced viability in response to DNA damage. The ataxia-telangiectasia mutated kinase (ATM) protein plays a critical role in the cellular response to double-strand DNA damage. We observed that PRL increased viability of breast cancer cells treated with doxorubicin or etoposide. The increase in cellular resistance is specific to the PRL receptor, because the PRL receptor antagonist, Δ1-9-G129R-hPRL, prevented the increase in viability. Two different HSP90 inhibitors, 17-allylamino-17-demethoxygeldanamycin and BIIB021, reduced the PRL-mediated increase in cell viability of doxorubicin-treated cells and led to a decrease in JAK2, ATM, and phosphorylated ATM protein levels. Inhibitors of JAK2 (G6) and ATM (KU55933) abolished the PRL-mediated increase in cell viability of DNA-damaged cells, supporting the involvement of each, as well as the crosstalk of ATM with the PRL pathway in the context of DNA damage. Drug synergism was detected between the ATM inhibitor (KU55933) and doxorubicin and between the HSP90 inhibitor (BIIB021) and doxorubicin. Short interfering RNA directed against ATM prevented the PRL-mediated increase in cell survival in two-dimensional cell culture, three-dimensional collagen gel cultures, and clonogenic cell survival, after doxorubicin treatment. Our results indicate that ATM contributes to the PRL-JAK2-STAT5-HSP90 pathway in mediating cellular resistance to DNA-damaging agents. Copyright © 2018 Endocrine Society.

  19. 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.

  20. 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

  1. 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

  2. The NK-1 Receptor Antagonist L-732,138 Induces Apoptosis and Counteracts Substance P-Related Mitogenesis in Human Melanoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Miguel Muñoz

    2010-04-01

    Full Text Available It has been recently demonstrated that substance P (SP and neurokinin-1 (NK-1 receptor antagonists induce cell proliferation and cell inhibition in human melanoma cells, respectively. However, the antitumor action of the NK-1 receptor antagonist L-732,138 on such cells is unknown. The aim of this study was to demonstrate an antitumor action of L-732,138 against three human melanoma cell lines (COLO 858, MEL HO, COLO 679. We found that L-732,138 elicits cell growth inhibition in a concentration dependent manner in the melanoma cells studied. Moreover, L-732,138 blocks SP mitogen stimulation. The specific antitumor action of L-732,138 occurred through the NK-1 receptor and melanoma cell death was by apoptosis. These findings indicate that the NK-1 receptor antagonist L-732,138 could be a new antitumor agent in the treatment of human melanoma.

  3. The NK-1 Receptor Antagonist L-732,138 Induces Apoptosis and Counteracts Substance P-Related Mitogenesis in Human Melanoma Cell Lines

    Energy Technology Data Exchange (ETDEWEB)

    Muñoz, Miguel, E-mail: mmunoz@cica.es; Rosso, Marisa; González-Ortega, Ana [Research Laboratory on Neuropeptides, Virgen del Rocío University Hospital, Sevilla (Spain); Coveñas, Rafael [Institute of Neurosciences of Castilla y León (INCYL), Laboratory of Neuroanatomy of the Peptidergic Systems (Laboratory 14), Salamanca (Spain)

    2010-04-20

    It has been recently demonstrated that substance P (SP) and neurokinin-1 (NK-1) receptor antagonists induce cell proliferation and cell inhibition in human melanoma cells, respectively. However, the antitumor action of the NK-1 receptor antagonist L-732,138 on such cells is unknown. The aim of this study was to demonstrate an antitumor action of L-732,138 against three human melanoma cell lines (COLO 858, MEL HO, COLO 679). We found that L-732,138 elicits cell growth inhibition in a concentration dependent manner in the melanoma cells studied. Moreover, L-732,138 blocks SP mitogen stimulation. The specific antitumor action of L-732,138 occurred through the NK-1 receptor and melanoma cell death was by apoptosis. These findings indicate that the NK-1 receptor antagonist L-732,138 could be a new antitumor agent in the treatment of human melanoma.

  4. Differential actions of antiparkinson agents at multiple classes of monoaminergic receptor. III. Agonist and antagonist properties at serotonin, 5-HT(1) and 5-HT(2), receptor subtypes.

    Science.gov (United States)

    Newman-Tancredi, Adrian; Cussac, Didier; Quentric, Yann; Touzard, Manuelle; Verrièle, Laurence; Carpentier, Nathalie; Millan, Mark J

    2002-11-01

    Although certain antiparkinson agents interact with serotonin (5-HT) receptors, little information is available concerning functional actions. Herein, we characterized efficacies of apomorphine, bromocriptine, cabergoline, lisuride, piribedil, pergolide, roxindole, and terguride at human (h)5-HT(1A), h5-HT(1B), and h5-HT(1D) receptors [guanosine 5'-O-(3-[(35)S]thio)triphosphate ([(35)S]GTPgammaS) binding], and at h5-HT(2A), h5-HT(2B), and h5-HT(2C) receptors (depletion of membrane-bound [(3)H]phosphatydilinositol). All drugs stimulated h5-HT(1A) receptors with efficacies (compared with 5-HT, 100%) ranging from modest (apomorphine, 35%) to high (cabergoline, 93%). At h5-HT(1B) receptors, efficacies varied from mild (terguride, 37%) to marked (cabergoline, 102%) and potencies were modest (pEC(50) values of 5.8-7.6): h5-HT(1D) sites were activated with a similar range of efficacies and greater potency (7.1-8.5). Piribedil and apomorphine were inactive at h5-HT(1B) and h5-HT(1D) receptors. At h5-HT(2A) receptors, terguride, lisuride, bromocriptine, cabergoline, and pergolide displayed potent (7.6-8.8) agonist properties (49-103%), whereas apomorphine and roxindole were antagonists and piribedil was inactive. Only pergolide (113%/8.2) and cabergoline (123%/8.6) displayed pronounced agonist properties at h5-HT(2B) receptors. At 5-HT(2C) receptors, lisuride, bromocriptine, pergolide, and cabergoline were efficacious (75-96%) agonists, apomorphine and terguride were antagonists, and piribedil was inactive. MDL100,907 and SB242,084, selective antagonists at 5-HT(2A) and 5-HT(2C) receptors, respectively, abolished these actions of pergolide, cabergoline, and bromocriptine. In conclusion, antiparkinson agents display markedly different patterns of agonist and antagonist properties at multiple 5-HT receptor subtypes. Although all show modest (agonist) activity at 5-HT(1A) sites, their contrasting actions at 5-HT(2A) and 5-HT(2C) sites may be of particular significance to their

  5. Selective adenosine A2A receptor agonists and antagonists protect against spinal cord injury through peripheral and central effects

    Directory of Open Access Journals (Sweden)

    Esposito Emanuela

    2011-04-01

    Full Text Available Abstract Background Permanent functional deficits following spinal cord injury (SCI arise both from mechanical injury and from secondary tissue reactions involving inflammation. Enhanced release of adenosine and glutamate soon after SCI represents a component in the sequelae that may be responsible for resulting functional deficits. The role of adenosine A2A receptor in central ischemia/trauma is still to be elucidated. In our previous studies we have demonstrated that the adenosine A2A receptor-selective agonist CGS21680, systemically administered after SCI, protects from tissue damage, locomotor dysfunction and different inflammatory readouts. In this work we studied the effect of the adenosine A2A receptor antagonist SCH58261, systemically administered after SCI, on the same parameters. We investigated the hypothesis that the main action mechanism of agonists and antagonists is at peripheral or central sites. Methods Spinal trauma was induced by extradural compression of SC exposed via a four-level T5-T8 laminectomy in mouse. Three drug-dosing protocols were utilized: a short-term systemic administration by intraperitoneal injection, a chronic administration via osmotic minipump, and direct injection into the spinal cord. Results SCH58261, systemically administered (0.01 mg/kg intraperitoneal. 1, 6 and 10 hours after SCI, reduced demyelination and levels of TNF-α, Fas-L, PAR, Bax expression and activation of JNK mitogen-activated protein kinase (MAPK 24 hours after SCI. Chronic SCH58261 administration, by mini-osmotic pump delivery for 10 days, improved the neurological deficit up to 10 days after SCI. Adenosine A2A receptors are physiologically expressed in the spinal cord by astrocytes, microglia and oligodendrocytes. Soon after SCI (24 hours, these receptors showed enhanced expression in neurons. Both the A2A agonist and antagonist, administered intraperitoneally, reduced expression of the A2A receptor, ruling out the possibility that the

  6. Effects of the NMDA receptor antagonist, D-CPPene, on sensitization to the operant decrement produced by naloxone in morphine-treated rats.

    Science.gov (United States)

    Bespalov, A Y; Medvedev, I O; Sukhotina, I A; Zvartau, E E

    2001-04-01

    Sensitization to the rate-decreasing effects of opioid antagonists induced by acute pretreatment with opioid agonists has been suggested to reflect initial changes in opioid systems that underlie physical dependence. Glutamate receptors are implicated in the development and expression of opioid dependence, and antagonists acting at the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors have been shown repeatedly to attenuate the severity of opioid withdrawal. The present study evaluated the ability of a competitive NMDA receptor antagonist, D-CPPene (SDZ EAA 494; 3-(2-carboxypiperazin-4-yl)-1-propenyl-1-phosphonic acid), to affect morphine-induced sensitization to naloxone in rats trained to lever-press on a multiple-trial, fixed-ratio 10 schedule of food reinforcement. D-CPPene (0.3-3 mg/kg) was administered either 4 h or 30 min prior to the test session. Morphine (10 mg/kg) or its vehicle was administered 4 h before naloxone challenge (0.3-3 mg/kg). D-CPPene failed to prevent morphine-induced potentiation of the naloxone-produced decrement in operant performance. Thus, these results suggest that agonist-induced sensitization to behavioral effects of opioid antagonists may be insensitive to NMDA receptor blockade.

  7. 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

  8. The alpha7 nicotinic acetylcholine receptor-selective antagonist, methyllycaconitine, partially protects against beta-amyloid1-42 toxicity in primary neuron-enriched cultures.

    Science.gov (United States)

    Martin, Shelley E; de Fiebre, Nancy Ellen C; de Fiebre, Christopher M

    2004-10-01

    Studies have suggested that the neuroprotective actions of alpha7 nicotinic agonists arise from activation of receptors and not from the extensive desensitization which rapidly follows activation. Here, we report that the alpha7-selective nicotinic antagonist, methyllycaconitine (MLA), protects against beta-amyloid-induced neurotoxicity; whereas the alpha4beta2-selective antagonist, dihydro-beta-erythroidine, does not. These findings suggest that neuroprotective actions of alpha7-acting agents arise from receptor inhibition/desensitization and that alpha7 antagonists may be useful neuroprotective agents.

  9. 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.

  10. 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

  11. Effects of the noncompetitive N-methyl-d-aspartate receptor antagonists ketamine and MK-801 on pain-stimulated and pain-depressed behaviour in rats.

    Science.gov (United States)

    Hillhouse, T M; Negus, S S

    2016-09-01

    Pain is a significant public health concern, and current pharmacological treatments have problematic side effects and limited effectiveness. N-methyl-d-aspartate (NMDA) glutamate receptor antagonists have emerged as one class of candidate treatments for pain because of the significant contribution of glutamate signalling in nociceptive processing. This study compared effects of the NMDA receptor antagonists ketamine and MK-801 in assays of pain-stimulated and pain-depressed behaviour in rats. The nonsteroidal anti-inflammatory drug ketoprofen was examined for comparison as a positive control. Intraperitoneal injection of dilute acid served as an acute visceral noxious stimulus to stimulate a stretching response or depress intracranial self-stimulation (ICSS) in male Sprague-Dawley rats. Ketamine (1.0-10.0 mg/kg) blocked acid-stimulated stretching but failed to block acid-induced depression of ICSS, whereas MK-801 (0.01-0.1 mg/kg) blocked both acid-stimulated stretching and acid-induced depression of ICSS. These doses of ketamine and MK-801 did not alter control ICSS in the absence of the noxious stimulus; however, higher doses of ketamine (10 mg/kg) and MK-801 (0.32 mg/kg) depressed all behaviour. Ketoprofen (1.0 mg/kg) blocked both acid-induced stimulation of stretching and depression of ICSS without altering control ICSS. These results support further consideration of NMDA receptor antagonists as analgesics; however, some NMDA receptor antagonists are more efficacious at attenuating pain-depressed behaviours. NMDA receptor antagonists produce dissociable effects on pain-depressed behaviour. Provides evidence that pain-depressed behaviours should be considered and evaluated when determining the antinociceptive effects of NMDA receptor antagonists. © 2016 European Pain Federation - EFIC®

  12. 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.

  13. 5-HT1A receptor antagonists reduce food intake and body weight by reducing total meals with no conditioned taste aversion.

    Science.gov (United States)

    Dill, M Joelle; Shaw, Janice; Cramer, Jeff; Sindelar, Dana K

    2013-11-01

    Serotonin acts through receptors controlling several physiological functions, including energy homeostasis regulation and food intake. Recent experiments demonstrated that 5-HT1A receptor antagonists reduce food intake. We sought to examine the microstructure of feeding with 5-HT1A receptor antagonists using a food intake monitoring system. We also examined the relationship between food intake, inhibition of binding and pharmacokinetic (PK) profiles of the antagonists. Ex vivo binding revealed that, at doses used in this study to reduce food intake, inhibition of binding of a 5-HT1A agonist by ~40% was reached in diet-induced obese (DIO) mice with a trend for higher binding in DIO vs. lean animals. Additionally, PK analysis detected levels from 2 to 24h post-compound administration. Male DIO mice were administered 5-HT1A receptor antagonists LY439934 (10 or 30 mg/kg, p.o.), WAY100635 (3 or 10mg/kg, s.c.), SRA-333 (10 or 30 mg/kg, p.o.), or NAD-299 (3 or 10mg/kg, s.c.) for 3 days and meal patterns were measured. Analyses revealed that for each antagonist, 24-h food intake was reduced through a specific decrease in the total number of meals. Compared to controls, meal number was decreased 14-35% in the high dose. Average meal size was not changed by any of the compounds. The reduction in food intake reduced body weight 1-4% compared to Vehicle controls. Subsequently, a conditioned taste aversion (CTA) assay was used to determine whether the feeding decrease might be an indicator of aversion, nausea, or visceral illness caused by the antagonists. Using a two bottle preference test, it was found that none of the compounds produced a CTA. The decrease in food intake does not appear to be a response to nausea or malaise. These results indicate that 5-HT1A receptor antagonist suppresses feeding, specifically by decreasing the number of meals, and induce weight loss without an aversive side effect. © 2013 Elsevier Inc. All rights reserved.

  14. Prolactin-stimulated mitogenesis in the Nb2 rat lymphoma cell: Lack of protoporphyrin IX effects

    Energy Technology Data Exchange (ETDEWEB)

    Gerrish, K.E.; Putnam, C.W.; Laird, H.E. II (Univ. of Arizona, Tucson (USA))

    1990-01-01

    Pharmacological characterization of the Nb2 cell peripheral-type benzodiazepine receptor (PBR) was determined using selected 1,4-benzodiazepines, PK 11195, and protoporphyrin IX (PPIX) to compete for specific ({sup 3}H) Ro5-4864 binding. These data suggest that PPIX possesses an affinity for the Nb2 cell PBR. We have previously reported that the peripheral benzodiazepine ligands, Ro5-4864 and PK 11195, modulate prolactin-stimulated mitogenesis in the Nb2 cell. In contrast, PPIX, a putative endogenous ligand for the PBR had no effect on prolactin-stimulated mitogenesis in the Nb2 cell over the concentration range from 10{sup {minus}15} M to 10{sup {minus}6} M. Taken together these data show that PPIX has an affinity for the Nb2 cell PBR but does not modulate prolactin-stimulated mitogenesis at concentrations which should bind to the Nb2 cell PBR.

  15. 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.

  16. 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.

  17. Design and Synthesis of a Series of L-trans-4-Substituted Prolines as Selective Antagonists for the Ionotropic Glutamate Receptors Including Functional and X-ray Crystallographic Studies of New Subtype Selective Kainic Acid Receptor Subtype 1 (GluK1) Antagonist (2S,4R)-4-(2-Carboxyphenoxy)pyrrolidine

    DEFF Research Database (Denmark)

    Krogsgaard-Larsen, Niels; Delgar, Claudia; Koch, Karina

    2017-01-01

    Ionotropic glutamate receptor antagonists are valuable tool compounds for studies of neurological pathways in the central nervous system. On the basis of rational ligand design, a new class of selective antagonists, represented by (2S,4R)-4-(2-carboxy-phenoxy)pyrrolidine-2-carboxylic acid (1b...... to the structure with glutamate, consistent with 1b being an antagonist. A structure-activity relationship study showed that the chemical nature of the tethering atom (C,O, or S) linking the pyrrolidine ring and the phenyl ring plays a key role in the receptor selectivity profile and that substituents......), for cloned homomeric kainic acid receptor subtype 1 (GluK1) was attained (Ki = 4 µM). In a functional assay, 1b displayed full antagonist activity with IC50 = 6 ± 2 µM. A crystal structure was obtained of 1b when bound in the ligand binding domain of GluK1. A domain opening of 13-14° was seen compared...

  18. Label-Free, LC-MS-Based Assays to Quantitate Small-Molecule Antagonist Binding to the Mammalian BLT1 Receptor.

    Science.gov (United States)

    Chen, Xun; Stout, Steven; Mueller, Uwe; Boykow, George; Visconti, Richard; Siliphaivanh, Phieng; Spencer, Kerrie; Presland, Jeremy; Kavana, Michael; Basso, Andrea D; McLaren, David G; Myers, Robert W

    2017-08-01

    We have developed and validated label-free, liquid chromatography-mass spectrometry (LC-MS)-based equilibrium direct and competition binding assays to quantitate small-molecule antagonist binding to recombinant human and mouse BLT1 receptors expressed in HEK 293 cell membranes. Procedurally, these binding assays involve (1) equilibration of the BLT1 receptor and probe ligand, with or without a competitor; (2) vacuum filtration through cationic glass fiber filters to separate receptor-bound from free probe ligand; and (3) LC-MS analysis in selected reaction monitoring mode for bound probe ligand quantitation. Two novel, optimized probe ligands, compounds 1 and 2, were identified by screening 20 unlabeled BLT1 antagonists for direct binding. Saturation direct binding studies confirmed the high affinity, and dissociation studies established the rapid binding kinetics of probe ligands 1 and 2. Competition binding assays were established using both probe ligands, and the affinities of structurally diverse BLT1 antagonists were measured. Both binding assay formats can be executed with high specificity and sensitivity and moderate throughput (96-well plate format) using these approaches. This highly versatile, label-free method for studying ligand binding to membrane-associated receptors should find broad application as an alternative to traditional methods using labeled ligands.

  19. Discovery of Dual ETA/ETB Receptor Antagonists from Traditional Chinese Herbs through in Silico and in Vitro Screening

    Directory of Open Access Journals (Sweden)

    Xing Wang

    2016-03-01

    Full Text Available Endothelin-1 receptors (ETAR and ETBR act as a pivotal regulator in the biological effects of ET-1 and represent a potential drug target for the treatment of multiple cardiovascular diseases. The purpose of the study is to discover dual ETA/ETB receptor antagonists from traditional Chinese herbs. Ligand- and structure-based virtual screening was performed to screen an in-house database of traditional Chinese herbs, followed by a series of in vitro bioassay evaluation. Aristolochic acid A (AAA was first confirmed to be a dual ETA/ETB receptor antagonist based intracellular calcium influx assay and impedance-based assay. Dose-response curves showed that AAA can block both ETAR and ETBR with IC50 of 7.91 and 7.40 μM, respectively. Target specificity and cytotoxicity bioassay proved that AAA is a selective dual ETA/ETB receptor antagonist and has no significant cytotoxicity on HEK293/ETAR and HEK293/ETBR cells within 24 h. It is a feasible and effective approach to discover bioactive compounds from traditional Chinese herbs using in silico screening combined with in vitro bioassay evaluation. The structural characteristic of AAA for its activity was especially interpreted, which could provide valuable reference for the further structural modification of AAA.

  20. 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.

  1. 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.

  2. A toll-like receptor 9 antagonist improves bladder function and white matter sparing in spinal cord injury.

    Science.gov (United States)

    David, Brian T; Sampath, Sujitha; Dong, Wei; Heiman, Adee; Rella, Courtney E; Elkabes, Stella; Heary, Robert F

    2014-11-01

    Spinal cord injury (SCI) affects motor, sensory, and autonomic functions. As current therapies do not adequately alleviate functional deficits, the development of new and more effective approaches is of critical importance. Our earlier investigations indicated that intrathecal administration of a toll-like receptor 9 (TLR9) antagonist, cytidine-phosphate-guanosine oligodeoxynucleotide 2088 (CpG ODN 2088), to mice sustaining a severe, mid-thoracic contusion injury diminished neuropathic pain but did not alter locomotor deficits. These changes were paralleled by a decrease in the pro-inflammatory response at the injury epicenter. Using the same SCI paradigm and treatment regimen, the current studies investigated the effects of the TLR9 antagonist on bladder function. We report that the TLR9 antagonist decreases SCI-elicited urinary retention and ameliorates bladder morphopathology without affecting kidney function. A significant improvement in white matter sparing was also observed, most likely due to alterations in the inflammatory milieu. These findings indicate that the TLR9 antagonist has beneficial effects not only in reducing sensory deficits, but also on bladder dysfunction and tissue preservation. Thus, modulation of innate immune receptor signaling in the spinal cord can impact the effects of SCI.

  3. 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.

  4. 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.

  5. Prostate response to prolactin in sexually active male rats

    Directory of Open Access Journals (Sweden)

    Garcia Luis I

    2006-05-01

    Full Text Available Abstract Background The prostate is a key gland in the sexual physiology of male mammals. Its sensitivity to steroid hormones is widely known, but its response to prolactin is still poorly known. Previous studies have shown a correlation between sexual behaviour, prolactin release and prostate physiology. Thus, here we used the sexual behaviour of male rats as a model for studying this correlation. Hence, we developed experimental paradigms to determine the influence of prolactin on sexual behaviour and prostate organization of male rats. Methods In addition to sexual behaviour recordings, we developed the ELISA procedure to quantify the serum level of prolactin, and the hematoxilin-eosin technique for analysis of the histological organization of the prostate. Also, different experimental manipulations were carried out; they included pituitary grafts, and haloperidol and ovine prolactin treatments. Data were analyzed with a One way ANOVA followed by post hoc Dunnet test if required. Results Data showed that male prolactin has a basal level with two peaks at the light-dark-light transitions. Consecutive ejaculations increased serum prolactin after the first ejaculation, which reached the highest level after the second, and started to decrease after the third ejaculation. These normal levels of prolactin did not induce any change at the prostate tissue. However, treatments for constant elevations of serum prolactin decreased sexual potency and increased the weight of the gland, the alveoli area and the epithelial cell height. Treatments for transient elevation of serum prolactin did not affect the sexual behaviour of males, but triggered these significant effects mainly at the ventral prostate. Conclusion The prostate is a sexual gland that responds to prolactin. Mating-induced prolactin release is required during sexual encounters to activate the epithelial cells in the gland. Here we saw a precise mechanism controlling the release of prolactin

  6. 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.

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

    DEFF Research Database (Denmark)

    Joseph, Lauren; Thomsen, Morgane

    2017-01-01

    Muscarinic M1/M4 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 (SD) effects, but the receptor subtypes mediating those...

  8. 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...

  9. Stimulatory effects of adenosine on prolactin secretion in the pituitary gland of the rat

    Directory of Open Access Journals (Sweden)

    D.L.W. Picanço-Diniz

    2002-07-01

    Full Text Available We investigated the effects of adenosine on prolactin (PRL secretion from rat anterior pituitaries incubated in vitro. The administration of 5-N-methylcarboxamidoadenosine (MECA, an analog agonist that preferentially activates A2 receptors, induced a dose-dependent (1 nM to 1 µM increase in the levels of PRL released, an effect abolished by 1,3-dipropyl-7-methylxanthine, an antagonist of A2 adenosine receptors. In addition, the basal levels of PRL secretion were decreased by the blockade of cyclooxygenase or lipoxygenase pathways, with indomethacin and nordihydroguaiaretic acid (NDGA, respectively. The stimulatory effects of MECA on PRL secretion persisted even after the addition of indomethacin, but not of NDGA, to the medium. MECA was unable to stimulate PRL secretion in the presence of dopamine, the strongest inhibitor of PRL release that works by inducing a decrease in adenylyl cyclase activity. Furthermore, the addition of adenosine (10 nM mimicked the effects of MECA on PRL secretion, an effect that persisted regardless of the presence of LiCl (5 mM. The basal secretion of PRL was significatively reduced by LiCl, and restored by the concomitant addition of both LiCl and myo-inositol. These results indicate that PRL secretion is under a multifactorial regulatory mechanism, with the participation of different enzymes, including adenylyl cyclase, inositol-1-phosphatase, cyclooxygenase, and lipoxygenase. However, the increase in PRL secretion observed in the lactotroph in response to A2 adenosine receptor activation probably was mediated by mechanisms involving regulation of adenylyl cyclase, independent of membrane phosphoinositide synthesis or cyclooxygenase activity and partially dependent on lipoxygenase arachidonic acid-derived substances.

  10. 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.

  11. 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

  12. 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.

  13. Prolactin secretion: the impact of dynamic studies

    International Nuclear Information System (INIS)

    L'Hermite, M.; Degueldre, M.; Caufriez, A.; Delvoye, P.; Robyn, C.

    1975-01-01

    Human prolactin blood levels were determined by radioimmunoassay in basal condition and in response to various inhibiting and/or stimulating agents (levodopa, water overload, insulinic hypoglycaemia, synthetic TRH, sulpiride) in cases of disturbed hypothalamo-pituitary axis (failure to lactate, prolactin-secreting pituitary adenomas, acromegaly, other pituitary tumours, clinical panhypopituitarism). A blunted prolactin response to suckling was evidenced in 2 post-partum women who were unable to breast feed. Hyperprolactinaemia, whether related to the existence of a prolactin-producing adenoma or not was associated with the disappearance of the normal circadian pattern of prolactin secretion and with a blunted relative response to TRH; the latter phenomenon occurred also in acromegaly regardless of the basal prolactinaemia, and during the last trimester of pregnancy. Water overload was unsuccessful to suppress prolactin during the last trimester of pregnancy while the acute administration of levodopa was quite effective in about half of the patients with pituitary tumour. Therefore none of the dynamic tests presently studied allowed to attribute a hyperprolactinaemia to a pituitary tumour rather than to a functional disturbance. On the contrary, stimulation tests can help to locate the level of a defect in cases of hypopituitarism [fr

  14. Effects on prolactin secretion and binding to dopaminergic receptors in sleep-deprived lupus-prone mice

    Directory of Open Access Journals (Sweden)

    B.D. Palma

    2009-03-01

    Full Text Available Sleep disturbances have far-reaching effects on the neuroendocrine and immune systems and may be linked to disease manifestation. Sleep deprivation can accelerate the onset of lupus in NZB/NZWF1 mice, an animal model of severe systemic lupus erythematosus. High prolactin (PRL concentrations are involved in the pathogenesis of systemic lupus erythematosus in human beings, as well as in NZB/NZWF1 mice. We hypothesized that PRL could be involved in the earlier onset of the disease in sleep-deprived NZB/NZWF1 mice. We also investigated its binding to dopaminergic receptors, since PRL secretion is mainly controlled by dopamine. Female NZB/NZWF1 mice aged 9 weeks were deprived of sleep using the multiple platform method. Blood samples were taken for the determination of PRL concentrations and quantitative receptor autoradiography was used to map binding of the tritiated dopaminergic receptor ligands [³H]-SCH23390, [³H]-raclopride and [³H]-WIN35,428 to D1 and D2 dopaminergic receptors and dopamine transporter sites throughout the brain, respectively. Sleep deprivation induced a significant decrease in plasma PRL secretion (2.58 ± 0.95 ng/mL compared with the control group (25.25 ± 9.18 ng/mL. The binding to D1 and D2 binding sites was not significantly affected by sleep deprivation; however, dopamine transporter binding was significantly increased in subdivisions of the caudate-putamen - posterior (16.52 ± 0.5 vs 14.44 ± 0.6, dorsolateral (18.84 ± 0.7 vs 15.97 ± 0.7 and ventrolateral (24.99 ± 0.5 vs 22.54 ± 0.7 µCi/g, in the sleep-deprived mice when compared to the control group. These results suggest that PRL is not the main mechanism involved in the earlier onset of the disease observed in sleep-deprived NZB/NZWF1 mice and the reduction of PRL concentrations after sleep deprivation may be mediated by modifications in the dopamine transporter sites of the caudate-putamen.

  15. Molecular characterization of the gerbil C5a receptor and identification of a transmembrane domain V amino acid that is crucial for small molecule antagonist interaction.

    Science.gov (United States)

    Waters, Stephen M; Brodbeck, Robbin M; Steflik, Jeremy; Yu, Jianying; Baltazar, Carolyn; Peck, Amy E; Severance, Daniel; Zhang, Lu Yan; Currie, Kevin; Chenard, Bertrand L; Hutchison, Alan J; Maynard, George; Krause, James E

    2005-12-09

    Anaphylatoxin C5a is a potent inflammatory mediator associated with pathogenesis and progression of several inflammation-associated disorders. Small molecule C5a receptor (C5aR) antagonist development is hampered by species-specific receptor biology and the associated inability to use standard rat and mouse in vivo models. Gerbil is one rodent species reportedly responsive to small molecule C5aR antagonists with human C5aR affinity. We report the identification of the gerbil C5aR cDNA using a degenerate primer PCR cloning strategy. The nucleotide sequence revealed an open reading frame encoding a 347-amino acid protein. The cloned receptor (expressed in Sf9 cells) bound recombinant human C5a with nanomolar affinity. Alignment of the gerbil C5aR sequence with those from other species showed that a Trp residue in transmembrane domain V is the only transmembrane domain amino acid unique to small molecule C5aR antagonist-responsive species (i.e. gerbil, human, and non-human primate). Site-directed mutagenesis was used to generate human and mouse C5aRs with a residue exchange of this Trp residue. Mutation of Trp to Leu in human C5aR completely eliminated small molecule antagonist-receptor interaction. In contrast, mutation of Leu to Trp in mouse C5aR enabled small molecule antagonist-receptor interaction. This crucial Trp residue is located deeper within transmembrane domain V than residues reportedly involved in C5a- and cyclic peptide C5a antagonist-receptor interaction, suggesting a novel interaction site(s) for small molecule antagonists. These data provide insight into the basis for small molecule antagonist species selectivity and further define sites critical for C5aR activation and function.

  16. 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...

  17. 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

  18. 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.

  19. Tuning the brain for motherhood: prolactin-like central signalling in virgin, pregnant, and lactating female mice.

    Science.gov (United States)

    Salais-López, Hugo; Lanuza, Enrique; Agustín-Pavón, Carmen; Martínez-García, Fernando

    2017-03-01

    Prolactin is fundamental for the expression of maternal behaviour. In virgin female rats, prolactin administered upon steroid hormone priming accelerates the onset of maternal care. By contrast, the role of prolactin in mice maternal behaviour remains unclear. This study aims at characterizing central prolactin activity patterns in female mice and their variation through pregnancy and lactation. This was revealed by immunoreactivity of phosphorylated (active) signal transducer and activator of transcription 5 (pSTAT5-ir), a key molecule in the signalling cascade of prolactin receptors. We also evaluated non-hypophyseal lactogenic activity during pregnancy by administering bromocriptine, which suppresses hypophyseal prolactin release. Late-pregnant and lactating females showed significantly increased pSTAT5-ir resulting in a widespread pattern of immunostaining with minor variations between pregnant and lactating animals, which comprises nuclei of the sociosexual and maternal brain, including telencephalic (septum, nucleus of the stria terminalis, and amygdala), hypothalamic (preoptic, paraventricular, supraoptic, and ventromedial), and midbrain (periaqueductal grey) regions. During late pregnancy, this pattern was not affected by the administration of bromocriptine, suggesting it to be elicited mostly by non-hypophyseal lactogenic agents, likely placental lactogens. Virgin females displayed, instead, a variable pattern of pSTAT5-ir restricted to a subset of the brain nuclei labelled in pregnant and lactating mice. A hormonal substitution experiment confirmed that estradiol and progesterone contribute to the variability found in virgin females. Our results reflect how the shaping of the maternal brain takes place prior to parturition and suggest that lactogenic agents are important candidates in the development of maternal behaviours already during pregnancy.

  20. Effects of light deprivation on prolactin regulation in the Golden Syrian hamster

    International Nuclear Information System (INIS)

    Massa, J.S.

    1986-01-01

    Pineal-mediated depressions in prolactin cell activity after light deprivation were studied in the male and female Golden Syrian hamster. Prolactin cell activity was determined by measuring radioimmunoassayable prolactin, newly synthesized prolactin, newly synthesized prolactin and prolactin mRNA levels in the pituitary. Serum prolactin was also measured by radioimmunoassay. Use of the recombinant DNA plasmid, pPRL-1, which contains the rat prolactin complimentary DNA sequence, was validated in this dissertation for measuring prolactin mRNA in the hamster. Male Hamsters blinded for 11, 21, or 42 days showed significant and progressively greater declines in prolactin mRNA levels which were completely prevented by pinealectomy. Female hamsters blinded for 28 days, however, showed no such decreases in prolactin cell activity if they continued to display estrous cyclicity. After 12 weeks of blinding, females were acyclic and had dramatically depressed levels of prolactin cell activity. However, pinealectomy did not completely prevent this decline due to blinding unless the females continue to display estrous cyclicity. In ovariectomized females, blinding caused a decline in prolactin cell activity. In a separate study, significant changes in prolactin cell activity during the estrous cycle were seen in untreated normally cycling female hamsters. These changes in prolactin mRNA, prolactin synthesis, and radioimmunoassayable prolactin in the pituitary were measured in the morning, when, consistent with other reports, no differences in serum prolactin were observed

  1. 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.

  2. Association between Interleukin-1 Receptor Antagonist (IL1RN) Variable Number of Tandem Repeats (VNTR) Polymorphism and Pulmonary Tuberculosis.

    Science.gov (United States)

    Hashemi, Mohammad; Naderi, Mohammad; Ebrahimi, Mahboubeh; Amininia, Shadi; Bahari, Gholamreza; Taheri, Mohsen; Eskandari-Nasab, Ebrahim; Ghavami, Saeid

    2015-02-01

    Macrophages and T-lymphocytes are involved in immune response to Mycobacterium tuberculosis. Macrophage produces interleukin (IL)-1 as an inflammatory mediator. IL-1 receptor antagonist (IL1-Ra) is a natural antagonist of IL-1 receptors. In this study we aimed to examine the possible association between the variable number of tandem repeats (VNTR) of the IL-1 receptor antagonist (IL1RN) gene and pulmonary tuberculosis (TB) in a sample of Iranian population. Our study is a case-control study and we examined the VNTR of the IL1RN gene in 265 PTB and 250 healthy subjects by PCR. Neither the overall chi-square comparison of PTB and control subjects nor the logistic regression analysis indicated any association between VNTR IL1RN polymorphism and PTB. Our data suggest that VNTR IL1RN polymorphism may not be associated with the risk of PTB in a sample of Iranian population. Larger studies with different ethnicities are needed to find out the impact of IL1RN VNTR polymorphism on risk of developing TB.

  3. 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.

  4. 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.

  5. 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)

  6. 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.

  7. The oxytocin/vasopressin receptor antagonist atosiban delays the gastric emptying of a semisolid meal compared to saline in human

    Directory of Open Access Journals (Sweden)

    Ekberg Olle

    2006-03-01

    Full Text Available Abstract Background Oxytocin is released in response to a meal. Further, mRNA for oxytocin and its receptor have been found throughout the gastrointestinal (GI tract. The aim of this study was therefore to examine whether oxytocin, or the receptor antagonist atosiban, influence the gastric emptying. Methods Ten healthy volunteers (five men were examined regarding gastric emptying at three different occasions: once during oxytocin stimulation using a pharmacological dose; once during blockage of the oxytocin receptors (which also blocks the vasopressin receptors and thereby inhibiting physiological doses of oxytocin; and once during saline infusion. Gastric emptying rate (GER was assessed and expressed as the percentage reduction in antral cross-sectional area from 15 to 90 min after ingestion of rice pudding. The assessment was performed by real-time ultrasonography. At the same time, the feeling of satiety was registered using visual satiety scores. Results Inhibition of the binding of endogenous oxytocin by the receptor antagonist delayed the GER by 37 % compared to saline (p = 0.037. In contrast, infusion of oxytocin in a dosage of 40 mU/min did not affect the GER (p = 0.610. Satiation scores areas in healthy subjects after receiving atosiban or oxytocin did not show any significant differences. Conclusion Oxytocin and/or vasopressin seem to be regulators of gastric emptying during physiological conditions, since the receptor antagonist atosiban delayed the GER. However, the actual pharmacological dose of oxytocin in this study had no effect. The effect of oxytocin and vasopressin on GI motility has to be further evaluated.

  8. The ability of H1 or H2 receptor antagonists or their combination in counteracting the glucocorticoid-induced alveolar bone loss in rats.

    Science.gov (United States)

    Ezzat, Bassant A; Abbass, Marwa M S

    2014-02-01

    The aim of the present study was to compare between three possible osteoporotic treatments in prevention of glucocorticoid-induced alveolar bone loss. Fifty adult female Wistar rats with an average weight 150-200 g were randomized into five groups: group I (control) was intraperitoneally injected with saline. The other experimental groups (II & III, IV & V) were intraperitoneally injected with 200 µg/100 g body weight dexamethasone. The experimental groups III, IV and V received intraperitoneal injection of 10 mg/kg/day pheniramine maleate (H1 receptor antagonist), ranitidine hydrochloride (H2 receptor antagonist) and concomitant doses of both H1 & H2 receptor antagonists respectively. After 30 days, the rats have been sacrificed. The mandibles were examined histologically, histochemically and histomorphometrically. The bone mineral density was measured using dual-energy X-ray absorptiometry (DEXA). Histopathologically the glucocorticoid group showed wide medullary cavities with wide osteocytic lacunae. These marrow cavities were reduced in the prophylactic groups (III, IV) but increased in group V. Bone histomorphometric analysis revealed improvement in static bone parameters in groups III and IV and deterioration in group V in comparison to group II. The DEXA revealed significant reduction in the bone mineral density in all experimental groups compared to the control group. In a rat model, the administration of H1 or H2 receptor antagonists separately could minimize the alveolar bone loss caused by the administration of glucocorticoids while concomitant administration of both H1 and H2 receptor antagonists deteriorated the bone condition. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  9. 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.

  10. 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.

  11. Effect of the low-affinity, noncompetitive N-methyl-D-aspartate receptor antagonist dextromethorphan on visceral perception in healthy volunteers

    NARCIS (Netherlands)

    Kuiken, S. D.; Lei, A.; Tytgat, G. N. J.; Holman, R.; Boeckxstaens, G. E. E.

    2002-01-01

    Background: The use of N-methyl-d-aspartate (NMDA) receptor antagonists may hold promise for the treatment of pain of visceral origin, in particular in conditions characterized by visceral hypersensitivity. Aim: To study the effect of dextromethorphan, a low affinity, non-competitive NMDA receptor

  12. Stress-induced release of anterior pituitary hormones: Effect of H3 receptor-mediated inhibition of histaminergic activity or posterior hypothalamic lesion

    DEFF Research Database (Denmark)

    Knigge, U.; Søe-Jensen, P.; Jørgensen, Henrik

    1999-01-01

    Histamine receptors, corticotropin, *Gb-endorphin, prolactin, adrenal steroids, stress, endotoxin, serotonin......Histamine receptors, corticotropin, *Gb-endorphin, prolactin, adrenal steroids, stress, endotoxin, serotonin...

  13. Dual orexin receptor antagonists show distinct effects on locomotor performance, ethanol interaction and sleep architecture relative to gamma-aminobutyric acid-A receptor modulators

    Directory of Open Access Journals (Sweden)

    Andres D. Ramirez

    2013-12-01

    Full Text Available Dual orexin receptor antagonists (DORAs are a potential treatment for insomnia that function by blocking both the orexin 1 and orexin 2 receptors. The objective of the current study was to further confirm the impact of therapeutic mechanisms targeting insomnia on locomotor coordination and ethanol interaction using DORAs and gamma-aminobutyric acid (GABA-A receptor modulators of distinct chemical structure and pharmacologic properties in the context of sleep-promoting potential. The current study compared rat motor co-ordination after administration of DORAs, DORA-12 and almorexant, and GABA-A receptor modulators, zolpidem, eszopiclone and diazepam, alone or each in combination with ethanol. Motor performance was assessed by measuring time spent walking on a rotarod apparatus. Zolpidem, eszopiclone and diazepam (0.3–30 mg/kg administered orally [PO] impaired rotarod performance in a dose-dependent manner. Furthermore, all three GABA-A receptor modulators potentiated ethanol- (0.25–1.25 g/kg induced impairment on the rotarod. By contrast, neither DORA-12 (10–100 mg/kg, PO nor almorexant (30–300 mg/kg, PO impaired motor performance alone or in combination with ethanol. In addition, distinct differences in sleep architecture were observed between ethanol, GABA-A receptor modulators (zolpidem, eszopiclone and diazepam and DORA-12 in electroencephalogram studies in rats. These findings provide further evidence that orexin receptor antagonists have an improved motor side-effect profile compared with currently available sleep-promoting agents based on preclinical data and strengthen the rationale for further evaluation of these agents in clinical development.

  14. Combinations of physiologic estrogens with xenoestrogens alter calcium and kinase responses, prolactin release, and membrane estrogen receptor trafficking in rat pituitary cells

    Directory of Open Access Journals (Sweden)

    Watson Cheryl S

    2010-10-01

    Full Text Available Abstract Background Xenoestrogens such as alkylphenols and the structurally related plastic byproduct bisphenol A have recently been shown to act potently via nongenomic signaling pathways and the membrane version of estrogen receptor-α. Though the responses to these compounds are typically measured individually, they usually contaminate organisms that already have endogenous estrogens present. Therefore, we used quantitative medium-throughput screening assays to measure the effects of physiologic estrogens in combination with these xenoestrogens. Methods We studied the effects of low concentrations of endogenous estrogens (estradiol, estriol, and estrone at 10 pM (representing pre-development levels, and 1 nM (representing higher cycle-dependent and pregnancy levels in combinations with the same levels of xenoestrogens in GH3/B6/F10 pituitary cells. These levels of xenoestrogens represent extremely low contamination levels. We monitored calcium entry into cells using Fura-2 fluorescence imaging of single cells. Prolactin release was measured by radio-immunoassay. Extracellular-regulated kinase (1 and 2 phospho-activations and the levels of three estrogen receptors in the cell membrane (ERα, ERβ, and GPER were measured using a quantitative plate immunoassay of fixed cells either permeabilized or nonpermeabilized (respectively. Results All xenoestrogens caused responses at these concentrations, and had disruptive effects on the actions of physiologic estrogens. Xenoestrogens reduced the % of cells that responded to estradiol via calcium channel opening. They also inhibited the activation (phosphorylation of extracellular-regulated kinases at some concentrations. They either inhibited or enhanced rapid prolactin release, depending upon concentration. These latter two dose-responses were nonmonotonic, a characteristic of nongenomic estrogenic responses. Conclusions Responses mediated by endogenous estrogens representing different life stages are

  15. 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.

  16. 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.

  17. Prolactin suppresses a progestin-induced CK5-positive cell population in luminal breast cancer through inhibition of progestin-driven BCL6 expression

    Science.gov (United States)

    Sato, Takahiro; Tran, Thai H.; Peck, Amy R.; Girondo, Melanie A.; Liu, Chengbao; Goodman, Chelain R.; Neilson, Lynn M.; Freydin, Boris; Chervoneva, Inna; Hyslop, Terry; Kovatich, Albert J.; Hooke, Jeffrey A.; Shriver, Craig D.; Fuchs, Serge Y.; Rui, Hallgeir

    2014-01-01

    Prolactin controls the development and function of milk-producing breast epithelia but also supports growth and differentiation of breast cancer, especially luminal subtypes. A principal signaling mediator of prolactin, Stat5, promotes cellular differentiation of breast cancer cells in vitro, and loss of active Stat5 in tumors is associated with anti-estrogen therapy failure in patients. In luminal breast cancer progesterone induces a cytokeratin-5 (CK5)-positive basal cell-like population. This population possesses characteristics of tumor stem cells including quiescence, therapy-resistance, and tumor-initiating capacity. Here we report that prolactin counteracts induction of the CK5-positive population by the synthetic progestin R5020 in luminal breast cancer cells both in vitro and in vivo. CK5-positive cells were chemoresistant as determined by four-fold reduced rate of apoptosis following docetaxel exposure. Progestin-induction of CK5 was preceded by marked up-regulation of BCL6, an oncogene and transcriptional repressor critical for the maintenance of leukemia-initiating cells. Knockdown of BCL6 prevented induction of CK5-positive cell population by progestin. Prolactin suppressed progestin-induced BCL6 through Jak2-Stat5 but not Erk- or Akt-dependent pathways. In premenopausal but not postmenopausal patients with hormone receptor-positive breast cancer, tumor protein levels of CK5 correlated positively with BCL6, and high BCL6 or CK5 protein levels were associated with unfavorable clinical outcome. Suppression of progestin-induction of CK5-positive cells represents a novel pro-differentiation effect of prolactin in breast cancer. The present progress may have direct implications for breast cancer progression and therapy since loss of prolactin receptor-Stat5 signaling occurs frequently and BCL6 inhibitors currently being evaluated for lymphomas may have value for breast cancer. PMID:23708665

  18. Characterization of the binding of [3H]-(+/-)-L-364,718: a new potent, nonpeptide cholecystokinin antagonist radioligand selective for peripheral receptors

    International Nuclear Information System (INIS)

    Chang, R.S.; Lotti, V.J.; Chen, T.B.; Kunkel, K.A.

    1986-01-01

    [3H]-(+/-)-L-364,718 a new, potent and selective nonpeptide peripheral cholecystokinin (CCK) antagonist bound saturably and reversibly to rat pancreatic membranes. The radioligand recognized a single class of binding sites with a high affinity (Kd = 0.23 nM). The binding of [ 3 H]-(+/-)-L-364,718 was stereospecific in that the more biologically active (-)-enantiomer demonstrated greater potency than the (+)-enantiomer. The rank order of potency of various CCK agonists and antagonists in displacing [ 3 H]-(+/-)-L-364,718 correlated with their ability to displace [ 125 I]CCK-8 and their known pharmacological activities in peripheral tissues. However, the absolute potencies of agonists were greater in displacing [ 125 I]CCK-8 than [ 3 H]-(+/-)-L-364,718. As described for other physiologically relevant receptor systems, the potency for displacement of [ 3 H]-(+/-)-L-364,718 binding by CCK agonists, but not antagonists, was reduced by guanosine 5'-(beta, gamma-imido)triphosphate and NaCl and enhanced by MgCl 2 . [ 3 H]-(+/-)-L-364,718 also demonstrated specific binding to bovine gall bladder tissue but not guinea pig brain or gastric glands, consistent with its selectivity as a peripheral CCK antagonist. [ 3 H]-(+/-)-L-364,718 binding to pancreatic membranes was not affected by various pharmacological agents known to interact with other common peptide and nonpeptide receptor systems. These data indicate that [ 3 H]-(+/-)-L-364,718 represents a new potent nonpeptide antagonist radioligand for the study of peripheral CCK receptors which may allow differentiation of agonist and antagonist interactions

  19. 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...

  20. 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.

  1. Sex differences in the hypothalamic control of prolactin secretion

    International Nuclear Information System (INIS)

    Grattan, D.R.; Liu, L.; Bunn, S.J.

    2001-01-01

    Full text: Sex differences in the brain may arise from the organisational effects of exposure to sex steroids during development, or from the exposure to a differential hormonal milieu in the adult. There is a marked sex difference in the neuroendocrine mechanism that regulates prolactin secretion. Levels of prolactin in the blood are higher in females than in males. Similarly, basal activity of tuberoinfundibular dopamine (TIDA) neurons, which are involved in the tonic suppression of prolactin secretion, are two fold higher in females than in males. Prolactin is known to stimulate the activity of TIDA neurons, thereby regulating its own secretion by short-loop feedback. Hence, it is thought that elevated TIDA neuronal activity in females is induced by increased prolactin in the blood. We have recently demonstrated that prolactin stimulation of TIDA neurons requires the transcription factor, STAT5b. We have now investigated prolactin secretion in male and female STAT5b-deficient mice, to test the hypothesis that sex differences in TIDA neuronal activity are dependent on stimulation by prolactin acting through STAT5b. Prolactin levels in blood were measured by radioimmunoassay, and TIDA activity was assessed by measuring concentrations of the dopamine metabolite DOPAC in the median eminence by HPLC, and by measuring tyrosine hydroxylase mRNA in the arcuate nucleus by real-time RT-PCR. The data demonstrate marked gender differences in the activity of TIDA neurons. While TIDA activity in STAT5b-deficient mice was reduced compared to wild type, the sex difference persisted. Since STAT5b is required for the actions of prolactin on these neurons, we can conclude that the sexual dimorphism in brain function is independent of gender differences in blood levels of prolactin. It seems likely that differential exposure to gonadal steroid hormones, either during development or in adulthood, might underlie the sex difference in TIDA neuronal activity. Copyright (2001

  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. Cellular and behavioural profile of the novel, selective neurokinin1 receptor antagonist, vestipitant: a comparison to other agents.

    Science.gov (United States)

    Brocco, Mauricette; Dekeyne, Anne; Mannoury la Cour, Clotilde; Touzard, Manuelle; Girardon, Sylvie; Veiga, Sylvie; de Nanteuil, Guillaume; deJong, Trynke R; Olivier, Berend; Millan, Mark J

    2008-10-01

    This study characterized the novel neurokinin (NK)(1) antagonist, vestipitant, under clinical evaluation for treatment of anxiety and depression. Vestipitant possessed high affinity for human NK(1) receptors (pK(i), 9.4), and potently blocked Substance P-mediated phosphorylation of Extracellular-Regulated-Kinase. In vivo, it occupied central NK(1) receptors in gerbils (Inhibitory Dose(50), 0.11 mg/kg). At similar doses, it abrogated nociception elicited by formalin in gerbils, and blocked foot-tapping and locomotion elicited by the NK(1) agonist, GR73632, in gerbils and guinea pigs, respectively. Further, vestipitant attenuated fear-induced foot-tapping in gerbils, separation-induced distress-vocalizations in guinea pigs, marble-burying behaviour in mice, and displayed anxiolytic actions in Vogel conflict and fear-induced ultrasonic vocalization procedures in rats. These actions were mimicked by CP99,994, L733,060 and GR205,171 which acted stereoselectively vs its less active isomer, GR226,206. In conclusion, vestipitant is a potent NK(1) receptor antagonist: its actions support the utility of NK(1) receptor blockade in the alleviation of anxiety and, possibly, depression.

  4. 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

  5. Competitive (AP7) and non-competitive (MK-801) NMDA receptor antagonists differentially alter glucose utilization in rat cortex

    International Nuclear Information System (INIS)

    Clow, D.W.; Lee, S.J.; Hammer, R.P. Jr.

    1991-01-01

    The effects of D,L-2-amino-7-phosphonoheptanoic acid (AP7), a competitive N-methyl-D-aspartate (NMDA) receptor antagonist, and MK-801, a non-competitive NMDA receptor antagonist, on regional brain metabolism were studied in unanesthetized, freely moving rats by using the quantitative 14 C2-deoxyglucose autoradiographic procedure. AP7 (338 or 901 mg/kg) produced a dose-dependent decrease of metabolic activity throughout most of the regions studied including sensory, motor, and limbic cortices. In contrast, MK-801 (0.1 or 1.0 mg/kg) resulted in a dose-dependent decrease of metabolic activity in sensory cortices, and an increase in limbic regions such as the hippocampal stratum lacunosum moleculare and entorhinal cortex. MK-801 also produced a biphasic response in agranular motor cortex, whereby the low dose increased while the high dose decreased labeling. In addition, MK-801 produced heterogeneous effects on regional cerebral metabolism in sensory cortices. Metabolic activity decreased in layer IV relative to layer Va following MK-801 treatment in primary somatosensory (SI) and visual (VI) cortices, suggesting a shift in activity from afferent fibers innervating layer IV to those innervating layer Va. MK-801 administration also decreased metabolic activity in granular SI relative to dysgranular SI, and in VI relative to secondary visual cortex (VII), thus providing a relative sparing of activity in dysgranular SI and VII. Thus, the non-competitive NMDA receptor antagonist suppressed activity from extrinsic neocortical sources, enhancing relative intracortical activity and stimulating limbic regions, while the competitive NMDA antagonist depressed metabolic activity in all cortical regions

  6. 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, ...

  7. Behavioural profiles in the mouse defence test battery suggest anxiolytic potential of 5-HT(1A) receptor antagonists.

    Science.gov (United States)

    Griebel, G; Rodgers, R J; Perrault, G; Sanger, D J

    1999-05-01

    Compounds varying in selectivity as 5-HT1A receptor antagonists have recently been reported to produce anxiolytic-like effects comparable to those of benzodiazepines in the mouse elevated plus-maze procedure. In view of the potential clinical significance of these findings, the present experiments compared the behavioural effects of diazepam (0.5-3.0 mg/kg) with those of several non-selective 5-HT1A receptor antagonists [NAN-190, 0.1-3.0 mg/kg, MM-77, 0.03-1.0 mg/kg, (S)-UH-301, 0.3-3.0 mg/kg and pindobind-5-HT1A, 0.03-1.0 mg/kg], and three selective 5-HT1A receptor antagonists (WAY100635, 0.01-3.0 mg/kg, p-MPPI, 0.1-3.0 mg/kg and SL88.0338, 0.3-3.0 mg/kg) in the mouse defence test battery (MDTB). In this well-validated anxiolytic screening test, Swiss mice are directly confronted with a natural threat (a rat) as well as situations associated with this threat. Primary measures taken during and after rat confrontation were flight, risk assessment (RA), defensive threat/attack and escape attempts. Diazepam significantly decreased flight reactions after the rat was introduced into the runway, reduced RA activities of mice chased by the rat, increased RA responses displayed when subjects were constrained in a straight alley and reduced defensive upright postures and biting upon forced contact. All the selective 5-HT1A receptor antagonists and NAN-190 also reduced flight, RA in the chase test, and defensive threat and attack behaviours. (S)-UH-301 and pindobind-5-HT1A reduced RA in the chase test, but only partially modified defensive threat and attack. Unlike the other drugs tested, MM-77 produced significant effects only at doses which also markedly reduced spontaneous locomotor activity, suggesting a behaviourally non-specific action. In contrast to diazepam, the 5-HT1A receptor ligands failed to affect RA in the straight alley test. Following removal of the rat from the test area, only diazepam and (S)-UH-301 reduced escape behaviour (contextual defence) at doses

  8. Modelling of absorption, distribution and physicochemical properties of AT1 receptor antagonists / Modelovanie absorpcie, distribúcie a fyzikálnochemických vlastnosti antagonistov AT1 receptorov

    Directory of Open Access Journals (Sweden)

    Ježko Pavol

    2015-12-01

    Full Text Available The theoretical chemistry methods were used to elucidate absorption, distribution and physicochemical properties of AT1 receptor antagonists and dual angiotensin II and endothelin A receptor antagonist (PS-433540. Computed partition coefficients (ALOGPS method studied for drugs varied between 2.98 and 6.66. Neutral compounds are described as lipophilic drugs. Telmisartan is a drug with the highest lipophilicity. The neutral forms of the studied AT1 receptor antagonists are practically insoluble in water, and their computed solubilities is in interval between 2.04 and 22.65 mg/l (ALOGpS method. The calculated pKa values for tetrazolyle moiety are in the range 3.92-5.00 and for carboxylic moiety 3.12-5.50. Telmisartan (polar surface area = 72.95 A and irbesartan (polar surface area = 87.14 A belong to the AT1 receptor antagonists with increased absorption.

  9. Crystal structure of the adenosine A 2A receptor bound to an antagonist reveals a potential allosteric pocket

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Bingfa; Bachhawat, Priti; Chu, Matthew Ling-Hon; Wood, Martyn; Ceska, Tom; Sands, Zara A.; Mercier, Joel; Lebon, Florence; Kobilka, Tong Sun; Kobilka, Brian K. (Stanford-MED); (ConfometRx); (UCB Pharma)

    2017-02-06

    The adenosine A2A receptor (A2AR) has long been implicated in cardiovascular disorders. As more selective A2AR ligands are being identified, its roles in other disorders, such as Parkinson’s disease, are starting to emerge, and A2AR antagonists are important drug candidates for nondopaminergic anti-Parkinson treatment. Here we report the crystal structure of A2A receptor bound to compound 1 (Cmpd-1), a novel A2AR/N-methyl D-aspartate receptor subtype 2B (NR2B) dual antagonist and potential anti-Parkinson candidate compound, at 3.5 Å resolution. The A2A receptor with a cytochrome b562-RIL (BRIL) fusion (A2AR–BRIL) in the intracellular loop 3 (ICL3) was crystallized in detergent micelles using vapor-phase diffusion. Whereas A2AR–BRIL bound to the antagonist ZM241385 has previously been crystallized in lipidic cubic phase (LCP), structural differences in the Cmpd-1–bound A2AR–BRIL prevented formation of the lattice observed with the ZM241385–bound receptor. The crystals grew with a type II crystal lattice in contrast to the typical type I packing seen from membrane protein structures crystallized in LCP. Cmpd-1 binds in a position that overlaps with the native ligand adenosine, but its methoxyphenyl group extends to an exosite not previously observed in other A2AR structures. Structural analysis revealed that Cmpd-1 binding results in the unique conformations of two tyrosine residues, Tyr91.35 and Tyr2717.36, which are critical for the formation of the exosite. The structure reveals insights into antagonist binding that are not observed in other A2AR structures, highlighting flexibility in the binding pocket that may facilitate the development of A2AR-selective compounds for the treatment of Parkinson’s disease.

  10. 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

  11. Assay method for organic calcium antagonist drugs and a kit for such an assay

    International Nuclear Information System (INIS)

    Snyder, S. H.; Gould, R. J.

    1985-01-01

    A method for measuring the level of organic calcium antagonist drug in a body fluid comprises preparing a mixture of a radioactive calcium antagonist drug, a body fluid containing a calcium antagonist drug and a calcium antagonist receptor material, measuring the radioactivity of the radioactive calcium antagonist drug bound to said calcium antagonist receptor material and deriving the concentration of the calcium antagonist drug in the body fluid from a standard curve indicating the concentration of calcium antagonist drug versus inhibition of binding of said radioactive calcium antagonist drug to said receptor sites caused by the calcium antagonist drug in said body fluid. A kit for measuring the level of an organic calcium drug comprises a receptacle containing a radioactive calcium antagonist drug, a calcium antagonist receptor material and a standard amount of a nonradioactive calcium antagonist drug

  12. Receptors for luteinizing hormone-releasing hormone (LHRH) in benign prostatic hyperplasia (BPH) as potential molecular targets for therapy with LHRH antagonist cetrorelix.

    Science.gov (United States)

    Rozsa, Bernadett; Nadji, Mehrdad; Schally, Andrew V; Dezso, Balazs; Flasko, Tibor; Toth, Gyorgy; Mile, Melinda; Block, Norman L; Halmos, Gabor

    2011-04-01

    The majority of men will develop symptoms of benign prostatic hyperplasia (BPH) after 70 years of age. Various studies indicate that antagonists of LHRH, such as cetrorelix, exert direct inhibitory effects on BPH mediated by specific LHRH receptors. Our aim was to investigate the mRNA for LHRH and LHRH receptors and the expression of LHRH receptors in specimens of human BPH. The expression of mRNA for LHRH (n=35) and LHRH receptors (n=55) was investigated by RT-PCR in surgical specimens of BPH, using specific primers. The characteristics of binding sites for LHRH on 20 samples were determined by ligand competition assays. The LHRH receptor expression was also examined in 64 BPH specimens by immunohistochemistry. PCR products for LHRH were found in 18 of 35 (51%) BPH tissues and mRNA for LHRH receptors was detected in 39 of 55 (71%) BPH specimens. Eighteen of 20 (90%) samples showed a single class of high affinity binding sites for [D-Trp(6) ]LHRH with a mean K(d) of 4.04 nM and a mean B(max) of 527.6 fmol/mg membrane protein. LHRH antagonist cetrorelix showed high affinity binding to LHRH receptors in BPH. Positive immunohistochemical reaction for LHRH receptors was present in 42 of 64 (67%) BPH specimens. A high incidence of LHRH receptors in BPH supports the use of LHRH antagonists such as cetrorelix, for treatment of patients with lower urinary tract symptoms from BPH. Copyright © 2010 Wiley-Liss, Inc.

  13. 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...

  14. Novel 5-HT5A receptor antagonists ameliorate scopolamine-induced working memory deficit in mice and reference memory impairment in aged rats.

    Science.gov (United States)

    Yamazaki, Mayako; Okabe, Mayuko; Yamamoto, Noriyuki; Yarimizu, Junko; Harada, Katsuya

    2015-03-01

    Despite the human 5-HT5A receptor being cloned in 1994, the biological function of this receptor has not been extensively characterized due to a lack of specific ligands. We recently reported that the selective 5-HT5A receptor antagonist ASP5736 ameliorated cognitive impairment in several animal models of schizophrenia. Given that areas of the brain with high levels of 5-HT5A receptor expression, such as the hippocampus and cerebral cortex, have important functions in cognition and memory, we evaluated the chemically diverse, potent and brain-penetrating 5-HT5A receptor antagonists ASP5736, AS2030680, and AS2674723 in rodent models of cognitive dysfunction associated with dementia. Each of these compounds exhibited a high affinity for recombinant 5-HT5A receptors that was comparable to that of the non-selective ligand of this receptor, lysergic acid diethylamide (LSD). Although each compound had a low affinity for other receptors, 5-HT5A was the only receptor for which all three compounds had a high affinity. Each of the three compounds ameliorated scopolamine-induced working memory deficit in mice and improved reference memory impairment in aged rats at similar doses. Further, ASP5736 decreased the binding of LSD to 5-HT5A receptors in the olfactory bulb of rats in a dose-dependent manner and occupied 15%-50% of brain 5-HT5A receptors at behaviorally effective doses. These results indicate that the 5-HT5A receptor is involved in learning and memory and that treatment with 5-HT5A receptor antagonists might be broadly effective for cognitive impairment associated with not only schizophrenia but also dementia. Copyright © 2015 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  15. 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.

  16. Dopamine inhibition of anterior pituitary adenylate cyclase is mediated through the high-affinity state of the D2 receptor

    International Nuclear Information System (INIS)

    Borgundvaag, B.; George, S.R.

    1985-01-01

    The diterpinoid forskolin stimulated adenylate cyclase activity (measured by conversion of [ 3 H]-ATP to [ 3 H]-cAMP) in anterior pituitary from male and female rats. Inhibition of stimulated adenylate cyclase activity by potent dopaminergic agonists was demonstrable only in female anterior pituitary. The inhibition of adenylate cyclase activity displayed a typically dopaminergic rank order of agonist potencies and could be completely reversed by a specific dopamine receptor antagonist. The IC 50 values of dopamine agonist inhibition of adenylate cyclase activity correlated with equal molarity with the dissociation constant of the high-affinity dopamine agonist-detected receptor binding site and with the IC 50 values for inhibition of prolactin secretion. These findings support the hypothesis that it is the high-affinity form of the D 2 dopamine receptor in anterior pituitary which is responsible for mediating the dopaminergic function of attenuating adenylate cyclase activity. 12 references, 4 figures, 1 table

  17. 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.

  18. 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.

  19. Night shift work and prolactin as a breast cancer risk factor

    Directory of Open Access Journals (Sweden)

    Agnieszka Bukowska

    2013-04-01

    Full Text Available Prolactin - a hormone secreted in a circadian rhythm acts as a regulator of growth and development of the mammary glands. It has been observed that working at night increases breast cancer risk in women. Night shift work, probably carcinogenic to humans (Group 2A IARC, can disrupt a circadian rhythm, and thus potentially alter the rhythm of prolactin secretion. The aim of our work was to review epidemiological evidence on the association between prolactin and the risk of breast cancer and the influence of work at night on prolactin secretion. Search was done in the Medline database by keywords (shift work, work at night, risk of breast cancer and prolactin. The increased proliferation of breast cells activated by prolactin can promote the development of cancer. The results of the largest epidemiological prospective studies suggest the association between prolactin levels and the risk of breast cancer in women. So far, only seven studies have investigated the association between work at night and prolactin secretion. In three studies lower concentrations of prolactin have been observed in night shift workers. No relationship between the night shift work duration and prolactin level in women have been reported. Night shift work can modify the profile of prolactin secretion in night workers, probably decreasing the secretion of this hormone at night. It is therefore unlikely that prolactin plays an important role in the development of breast cancer in women working at night. This conclusion is based on the results of a few epidemiological studies. Med Pr 2013;64(2:245–257

  20. Role of dopamine D4 receptors in copulatory behavior: Studies with selective D4 agonists and antagonists in male rats.

    Science.gov (United States)

    Sanna, Fabrizio; Contini, Andrea; Melis, Maria Rosaria; Argiolas, Antonio

    2015-10-01

    Dopamine influences the anticipatory and consummatory phases of sexual behavior, by acting on receptors of the D2 family (D2, D3 and D4) and in particular of the D2 subtype, although evidence for a role of D4 receptors in erectile function and copulatory behavior is also available. In order to clarify such a role of D4 receptors, the effect of selective D4 receptor agonists and antagonists on copulatory behavior of sexually potent male rats in classic copulation tests with a receptive female, was compared with that of apomorphine and haloperidol, a classic dopamine receptor agonist and antagonist, respectively. PD-168,077 (0.05-0.2mg/kg) and ABT-724 (0.01-0.04mg/kg), two selective D4 receptor agonists, given subcutaneously, improved dose-dependently copulatory behavior as shown by the decrease of mount frequency and post ejaculatory interval induced by PD-168,077, and of mount frequency, ejaculation latency, post ejaculatory and inter intromission intervals induced by ABT-724, and by the increase of ejaculation frequency and copulatory efficacy induced by both drugs. Conversely, L-745,870 (1-5mg/kg), a selective D4 receptor antagonist, given intraperitoneally, impaired dose-dependently copulatory behavior, as shown by the increase in intromission and ejaculation latencies, mount frequency, post ejaculatory interval and the decrease in ejaculation frequency and copulatory efficacy induced by this drug. L-745,870 (5mg/kg) administered before PD-168,077 (0.2mg/kg) or ABT-724 (0.04mg/kg), also abolished completely the facilitatory effects of both PD-168,077 and ABT-724 on sexual behavior. These results confirm the involvement of D4 receptors in specific aspects of male rat copulatory behavior that overlap only partially with those influenced by apomorphine and haloperidol. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Peripherally Administered Y2-Receptor Antagonist BIIE0246 Prevents Diet-Induced Obesity in Mice With Excess Neuropeptide Y, but Enhances Obesity in Control Mice.

    Science.gov (United States)

    Ailanen, Liisa; Vähätalo, Laura H; Salomäki-Myftari, Henriikka; Mäkelä, Satu; Orpana, Wendy; Ruohonen, Suvi T; Savontaus, Eriika

    2018-01-01

    Neuropeptide Y (NPY) plays an important role in the regulation of energy homeostasis in the level of central and sympathetic nervous systems (SNSs). Genetic silencing of peripheral Y 2 -receptors have anti-obesity effects, but it is not known whether pharmacological blocking of peripheral Y 2 -receptors would similarly benefit energy homeostasis. The effects of a peripherally administered Y 2 -receptor antagonist were studied in healthy and energy-rich conditions with or without excess NPY. Genetically obese mice overexpressing NPY in brain noradrenergic nerves and SNS (OE-NPY DβH ) represented the situation of elevated NPY levels, while wildtype (WT) mice represented the normal NPY levels. Specific Y 2 -receptor antagonist, BIIE0246, was administered (1.3 mg/kg/day, i.p.) for 2 or 4.5 weeks to OE-NPY DβH and WT mice feeding on chow or Western diet. Treatment with Y 2 -receptor antagonist increased body weight gain in both genotypes on chow diet and caused metabolic disturbances (e.g., hyperinsulinemia and hypercholesterolemia), especially in WT mice. During energy surplus (i.e., on Western diet), blocking of Y 2 -receptors induced obesity in WT mice, whereas OE-NPY DβH mice showed reduced fat mass gain, hepatic glycogen and serum cholesterol levels relative to body adiposity. Thus, it can be concluded that with normal NPY levels, peripheral Y 2 -receptor antagonist has no potential for treating obesity, but oppositely may even induce metabolic disorders. However, when energy-rich diet is combined with elevated NPY levels, e.g., stress combined with an unhealthy diet, Y 2 -receptor antagonism has beneficial effects on metabolic status.

  2. WAY 267,464, a non-peptide oxytocin receptor agonist, impairs social recognition memory in rats through a vasopressin 1A receptor antagonist action.

    Science.gov (United States)

    Hicks, Callum; Ramos, Linnet; Reekie, Tristan A; Narlawar, Rajeshwar; Kassiou, Michael; McGregor, Iain S

    2015-08-01

    Recent in vitro studies suggest that the oxytocin receptor (OTR) agonist WAY 267,464 has vasopressin 1A receptor (V1AR) antagonist effects. This might limit its therapeutic potential due to the positive involvement of the V1AR in social behavior. The objective of this study was to assess functional V1AR antagonist-like effects of WAY 267,464 in vivo using a test of social recognition memory. Adult experimental rats were tested for their recognition of a juvenile conspecific rat that they had briefly met 30 or 120 min previously. The modulatory effects of vasopressin (AVP), the selective V1AR antagonist SR49059, and WAY 267,464 were examined together with those of the selective OTR antagonist Compound 25 (C25). Drugs were administered immediately after the first meeting. Control rats showed recognition of juveniles at a 30 min, but not a 120 min retention interval. AVP (0.005, but not 0.001 mg/kg intraperitoneal (i.p.)) improved memory such that recognition was evident after 120 min. This was prevented by pretreatment with SR49059 (1 mg/kg) and WAY 267,464 (10, 30, and 100 mg/kg). Given alone, SR49059 (1 mg/kg) and WAY 267,464 (30 and 100 mg/kg) impaired memory at a 30 min retention interval. The impairment with WAY 267,464 was not prevented by C25 (5 mg/kg), suggesting V1AR rather than OTR mediation of the effect. Given alone, C25 also impaired memory. These results highlight a tonic role for endogenous AVP (and oxytocin) in social recognition memory and indicate that WAY 267,464 functions in vivo as a V1AR antagonist to prevent the memory-enhancing effects of AVP.

  3. 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.

  4. Changes in haematological indices following local application of interleukin-1 receptor antagonist protein after tenotomy in rabbits

    Directory of Open Access Journals (Sweden)

    Marko Pecin

    2017-01-01

    Full Text Available Interleukin-1 (IL-1 is the most important cytokine in the inflammation cascade activation in all tissues and is present in acute and chronic phases of inflammation. By blocking IL-1 binding to target cells, numerous inflammation processes are prevented. The use of autologous conditioned serum rich with IL-1 receptor antagonist protein (IL-1Ra is a novel treatment method of tendon inflammation in domestic animals and humans. Injections of autologous conditioned serum (ACS have demonstrated clinical efficacy and safety in animal models and humans in the treatment of osteoarthritis, disc prolapse and muscles and tendons injuries with low side effect. Neutropaenia, reduced white blood cell count, and infections or local irritations are described as side effects of IL-1 antagonist use in humans. Therefore, a study of blood changes in rabbits after local administration of IL-1Ra in the Achilles tendon tissue after iatrogenic inflammation was conducted. Interleukin-1 receptor antagonist protein was used to prevent and reduce tendon inflammation after longitudinal tenotomy. The study was done on 26 white Californian rabbits, divided into two equal groups consisting of 13 animals each; the experimental interleukin-1 receptor antagonist protein (irap group, and the control group. In the irap group, autologous serum rich with IL-1Ra was used (Orthokine®vet irap, Alfa-Arthro, Croatia. Differences between two groups were considered significant as changes in the blood for certain blood elements at P < 0.01. The P value was P = 0.0153 for the white blood cells, P = 0.00153 for neutrophils, P = 0.00017 and for platelets. In the control group, an increased platelet count was noticed in 70% of blood samples and a decreased neutrophil count was found in all of the irap group samples at the end of the study in comparison to the initial blood count prior to application.

  5. Prolactin suppresses malonyl-CoA concentration in human adipose tissue

    DEFF Research Database (Denmark)

    Nilsson, L. A.; Roepstorff, Carsten; Kiens, Bente

    2009-01-01

    Prolactin is best known for its involvement in lactation, where it regulates mechanisms that supply nutrients for milk production. In individuals with pathological hyperprolactinemia, glucose and fat homeostasis have been reported to be negatively influenced. It is not previously known, however......, whether prolactin regulates lipogenesis in human adipose tissue. The aim of this study was to investigate the effect of prolactin on lipogenesis in human adipose tissue in vitro. Prolactin decreased the concentration of malonyl-CoA, the product of the first committed step in lipogenesis, to 77......+/-6% compared to control 100+/-5% (p=0.022) in cultured human adipose tissue. In addition, prolactin was found to decrease glucose transporter 4 ( GLUT4) mRNA expression, which may cause decreased glucose uptake. In conclusion, we propose that prolactin decreases lipogenesis in human adipose tissue...

  6. Ariadne merione ecdysone receptor (AmEcR protein: An in silico approach for comparison of agonist and antagonist compounds

    Directory of Open Access Journals (Sweden)

    Chandran Sundaravadivelan

    2017-12-01

    Full Text Available Ecdysteroid signal transduction plays a major role in insect metamorphosis, 20-hydroxyecdysone (20E binds to the nuclear receptor composed of the ecdysone receptor ligand binding domine (EcR-LBD and triggers the developmental transitions. Ariadne merione ecdysone receptor (AmEcR cDNA was amplified and partially sequenced of about 553 bp, which encodes a polypeptide of 184 amino acids (aa. The theoretical molecular weight (MW, isoelectric point (pI and aliphatic index of the deduced AmEcR protein were predicted using BIOEDIT (v7.2.5 to be 21.192 kDa, 9.31 and 101.739 respectively. Identified ecdysone receptor gene of A. merione showed maximum similarity with Precis coenia gene. In this research, we have employed ligand-receptor engineering technique to screen a specific compound which plays antagonist role and assist to formulate an insect specific pesticide. The EcR protein 3D structure of AmEcR modeled using Schrödinger maestro and virtual screening was performed using 5554 molecules from Zinc database, where ZINC20031812 showed highest glide score of −6.257 and Etoxazole chosen on literature basis and showed best glide score −6.671. We have compared the antagonist with agonist (20E by molecular dynamics (MD simulation. Root Mean Square Deviation (RMSD value of agonist and antagonist indicates the binding were stable in water with a range of distance from 2.3 to 2.6 Å, 1.8 to 2.3 Å and 1.9 to 2.3 Å with a variation over the time scale of 1 ps. Since Etoxazole and ZINC20031812 are antagonists, computationally they were more stable than 20E. Keywords: Ariadne merione, 20 Hydroxyecdysone (20E, Etoxazole, Schrödinger

  7. 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

  8. Meta-diamide insecticides acting on distinct sites of RDL GABA receptor from those for conventional noncompetitive antagonists.

    Science.gov (United States)

    Nakao, Toshifumi; Banba, Shinich; Nomura, Michikazu; Hirase, Kangetsu

    2013-04-01

    The RDL GABA receptor is an attractive target of insecticides. Here we demonstrate that meta-diamides [3-benzamido-N-(4-(perfluoropropan-2-yl)phenyl)benzamides] are a distinct class of RDL GABA receptor antagonists showing high insecticidal activity against Spodoptera litura. We also suggest that the mode of action of the meta-diamides is distinct from that of conventional noncompetitive antagonists (NCAs), such as fipronil, picrotoxin, lindane, dieldrin, and α-endosulfan. Using a membrane potential assay, we examined the effects of the meta-diamide 3-benzamido-N-(2-bromo-4-(perfluoropropan-2-yl)-6-(trifluoromethyl)phenyl)-2-fluorobenzamide (meta-diamide 7) and NCAs on mutant Drosophila RDL GABA receptors expressed in Drosophila Mel-2 cells. NCAs had little or no inhibitory activity against at least one of the three mutant receptors (A2'S, A2'G, and A2'N), which were reported to confer resistance to NCAs. In contrast, meta-diamide 7 inhibited all three A2' mutant receptors, at levels comparable to its activity with the wild-type receptor. Furthermore, the A2'S·T6'V mutation almost abolished the inhibitory effects of all NCAs. However, meta-diamide 7 inhibited the A2'S・T6'S mutant receptor at the same level as its activity with the wild-type receptor. In contrast, a G336M mutation in the third transmembrane domain of the RDL GABA receptor abolished the inhibitory activities of meta-diamide 7, although the G336M mutation had little effect on the inhibitory activities of conventional NCAs. Molecular modeling studies also suggested that the binding site of meta-diamides was different from those of NCAs. Meta-diamide insecticides are expected to be prominent insecticides effective against A2' mutant RDL GABA receptors with a different mode of action. Copyright © 2013 Elsevier Ltd. All rights reserved.

  9. 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...

  10. 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

  11. 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

  12. 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.

  13. 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

  14. 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

  15. Serum prolactin revisited

    DEFF Research Database (Denmark)

    Overgaard, Martin; Pedersen, Susanne Møller

    2017-01-01

    regimes across commonly used automated immunoassay platforms. METHODS: Parametric total and monomeric gender-specific reference intervals were determined for six immunoassay methods using female (n=96) and male sera (n=127) from healthy donors. The reference intervals were validated using 27...... and macroprolactinemic; n=27) showed higher discordant classification [mean=2.8; 95% confidence interval (CI) 1.2-4.4] for the monomer reference interval method compared to the post-polyethylene glycol (PEG) recovery cutoff method (mean=1.8; 95% CI 0.8-2.8). The two monomer/macroprolactin discrimination methods did...... not differ significantly (p=0.089). Among macroprolactinemic sera evaluated by both discrimination methods, the Cobas and Architect/Kryptor prolactin assays showed the lowest and the highest number of misclassifications, respectively. CONCLUSIONS: Current automated immunoassays for prolactin testing require...

  16. 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...

  17. Stability of tramadol with three 5-HT3 receptor antagonists in polyolefin bags for patient-controlled delivery systems

    Directory of Open Access Journals (Sweden)

    Chen FC

    2016-06-01

    Full Text Available Fu-chao Chen,1 Jun Zhu,1 Bin Li,1 Fang-jun Yuan,1 Lin-hai Wang2 1Department of Pharmacy, Dongfeng Hospital, 2Department of Pharmacy, Renmin Hospital, Hubei University of Medicine, Shiyan, Hubei, People’s Republic of China Background: Mixing 5-hydroxytryptamine-3 (5-HT3 receptor antagonists with patient-controlled analgesia (PCA solutions of tramadol has been shown to decrease the incidence of nausea and vomiting associated with the use of tramadol PCA for postoperative pain. However, such mixtures are not commercially available, and the stability of the drug combinations has not been duly studied. The study aimed to evaluate the stability of tramadol with three 5-HT3 receptor antagonists in 0.9% sodium chloride injection for PCA administration.Materials and methods: Test samples were prepared by adding 1,000 mg tramadol hydrochloride, 8 mg ondansetron hydrochloride, and 6 mg granisetron hydrochloride or 5 mg tropisetron hydrochloride to 100 mL of 0.9% sodium chloride injection in polyolefin bags. The samples were prepared in triplicates, stored at either 25°C or 4°C for 14 days, and assessed using the following compatibility parameters: precipitation, cloudiness, discoloration, and pH. Chemical stability was also determined using a validated high-pressure liquid chromatography method.Results: All of the mixtures were clear and colorless throughout the initial observation period. No change in the concentration of tramadol hydrochloride occurred with any of the 5-HT3 receptor antagonists during the 14 days. Similarly, little or no loss of the 5-HT3 receptor antagonists occurred over the 14-day period.Conclusion: Our results suggest that mixtures of tramadol hydrochloride, ondansetron hydrochloride, granisetron hydrochloride, or tropisetron hydrochloride in 0.9% sodium chloride injection were physically and chemically stable for 14 days when stored in polyolefin bags at both 4°C and 25°C. Keywords: tramadol, ondansetron, granisetron

  18. Synthesis of 11C-SCH 23390, a dopamine D-1 receptor antagonist, for use in in vivo receptor binding studies with PET

    International Nuclear Information System (INIS)

    Halldin, Christer; Stone-Elander, Sharon; Farde, Lars; Ehrin, Erling; Fasth, Karl-Johan; Langstroem, Bengt; Sedvall, Goeran; Karolinska Hospital, Stockholm; Uppsala Univ.

    1986-01-01

    Central dopamine receptors are generally accepted to exist in at least two distinct subtypes: D-1 and D-2. Recently a benzazepine, SCH 23390, was reported to be a selective D-1 dopaminergic antagonist. PET studies of the radio-brominated 76 Br-SCH 23390 reported by Friedman, et al. indicated that the analog exhibits specific binding in the striatum of the monkey brain. Here we report the synthesis of 11 C-SCH 23390 suitable for the in vivo study of dopamine D-1 receptors in the human brain. (author)

  19. Selective Allosteric Antagonists for the G Protein-Coupled Receptor GPRC6A Based on the 2-Phenylindole Privileged Structure Scaffold

    DEFF Research Database (Denmark)

    Johansson, Henrik; Boesgaard, Michael Worch; Nørskov-Lauritsen, Lenea

    2015-01-01

    G protein-coupled receptors (GPCRs) represent a biological target class of fundamental importance in drug therapy. The GPRC6A receptor is a newly deorphanized class C GPCR that we recently reported for the first allosteric antagonists based on the 2-arylindole privileged structure scaffold (e.g., 1...

  20. Affinity and selectivity of PD156707, a novel nonpeptide endothelin antagonist, for human ET(A) and ET(B) receptors.

    Science.gov (United States)

    Maguire, J J; Kuc, R E; Davenport, A P

    1997-02-01

    We have determined the affinity and selectivity of a new nonpeptide antagonist PD156707 (sodium 2-benzo(1,3ioxol-5-yl-4-(4-methoxy-pheny l)-4-oxo-3-(3,4,5-trime tho xybenzyl)-but-2-enoate) for human endothelin (ET)(A) and ET(B) receptors. In human coronary artery and saphenous vein the affinity of the ET(A) receptor for PD156707 was 0.15 +/- 0.06 nM and 0.5 +/- 0.13 nM, respectively. Competition experiments in human left ventricle and kidney revealed that PD156707 had 1,000- to 15,000-fold selectivity for the ET(A) receptor over the ET(B) receptor. This selectivity was confirmed autoradiographically. In human coronary artery, mammary artery and saphenous vein PD156707 (3-300 nM) potently antagonized the vasoconstrictor responses to ET-1. The pA2 values estimated from the Gaddum-Schild equation were 8.07 +/- 0.09, 8.45 +/- 0.11 and 8.70 +/- 0.13, respectively. The concentration-response curves to ET-1 were shifted to the right in parallel fashion, without reduction of the maximum response. However, the regression lines fitted to the resulting Schild data deviated significantly from one. PD156707 appeared to be a more effective antagonist at lower concentrations than at the higher ones. It is possible that PD156707, a sodium salt, was reverting to a less soluble form which results in underestimation of its potency. These data show that PD156707 is a potent and selective antagonist at human ET(A) receptors and will be useful in clarifying the role of the endothelin peptides in human cardiovascular disease.

  1. 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.

  2. Prolactin and Psychopathology in Schizophrenia: A Literature Review and Reappraisal

    Directory of Open Access Journals (Sweden)

    Ravi Philip Rajkumar

    2014-01-01

    Full Text Available Secretion of the anterior pituitary hormone prolactin can be significantly increased by antipsychotic drugs, leading to a range of adverse effects in patients with schizophrenia. However, there is evidence from a variety of studies that prolactin may also be related to symptom profile and treatment response in these patients, and recent work has identified variations in prolactin secretion even in drug-free patients. In this paper, a selective review of all relevant studies pertaining to prolactin and schizophrenia, including challenge and provocation studies, is presented. The implications of this work are discussed critically. A tentative model, which synthesizes these findings and argues for a significant role for prolactin in the development of schizophrenia, is outlined.

  3. Seasonal prolactin secretion and its role in seasonal reproduction: a review.

    Science.gov (United States)

    Curlewis, J D

    1992-01-01

    The majority of seasonally breeding mammals show a seasonal pattern of prolactin secretion with peak concentrations in spring or summer and a nadir in autumn or winter. Photoperiod influences prolactin secretion via its effects on the secretion of the pineal hormone melatonin. Preliminary evidence suggests that the effects of melatonin on both prolactin and gonadotrophin secretion are via a common target area, possibly within the anterior hypothalamus, and that differences in response to photoperiod may be due to differences in the processing and/or interpretation of the melatonin signal. In contrast to seasonal gonadotrophin secretion, the seasonal changes in prolactin are not due to changes in the sensitivity of a feedback loop and so must be due to direct effects on the hypothalamic pathways that control prolactin secretion. Little else can be said with confidence about the neuroendocrine mechanisms that lead to the seasonal changes in prolactin secretion. Dopamine and noradrenaline turnover in the arcuate nucleus and median eminence decrease under short daylength. If catecholamine turnover in these structures is positively correlated with catecholamine concentrations in the long or short hypophysial portal vessels, it is unlikely that the decrease in prolactin concentration in winter is due to the effects of increased concentrations of dopamine or noradrenaline in the portal vessels. There is, however, evidence for increased pituitary sensitivity to dopamine under short daylength, so increased dopamine concentrations may not be required for suppression of prolactin secretion at this time. In addition to the diminished secretion of prolactin under short daylength, rate of prolactin synthesis and pituitary content of prolactin also decline although the mechanisms that regulate these changes are poorly understood. Although all seasonal breeders show a seasonal change in prolactin secretion, there are continuously breeding species in which prolactin secretion is

  4. Involvement of N-methyl-d-aspartate receptors in the antidepressant-like effect of 5-hydroxytryptamine 3 antagonists in mouse forced swimming test and tail suspension test.

    Science.gov (United States)

    Kordjazy, Nastaran; Haj-Mirzaian, Arya; Amiri, Shayan; Ostadhadi, Sattar; Amini-Khoei, Hossein; Dehpour, Ahmad Reza

    2016-02-01

    Recent evidence indicates that 5-hydroxytryptamine 3 (5-HT3) antagonists such as ondansetron and tropisetron exert positive behavioral effects in animal models of depression. Due to the ionotropic nature of 5-HT3 and N-methyl-d-aspartate (NMDA) receptors, plus their contribution to the pathophysiology of depression, we investigated the possible role of NMDA receptors in the antidepressant-like effect of 5-HT3 receptor antagonists in male mice. In order to evaluate the animals' behavior in response to different treatments, we performed open-field test (OFT), forced swimming test (FST), and tail-suspension test (TST), which are considered as valid tasks for measuring locomotor activity and depressive-like behaviors in mice. Our data revealed that intraperitoneal (i.p.) administration of tropisetron (5, 10, and 30mg/kg) and ondansetron (0.01, and 0.1μg/kg) significantly decreased the immobility time in FST and TST. Also, co-administration of subeffective doses of tropisetron (1mg/kg, i.p.) or ondansetron (0.001μg/kg, i.p.) with subeffective doses of NMDA receptor antagonists, ketamine (1mg/kg, i.p.), MK-801 (0.05mg/kg, i.p.) and magnesium sulfate (10mg/kg, i.p.) resulted in a reduced immobility time both in FST and TST. The subeffective dose of NMDA (NMDA receptor agonist, 75mg/kg, i.p.) abolished the effects of 5-HT3 antagonists in FST and TST, further supporting the presumed interaction between 5-HT3 and NMDA receptors. These treatments did not affect the locomotor behavior of animals in OFT. Finally, the results of our study suggest that the positive effects of 5-HT3 antagonists on the coping behavior of mice in FST and TST are at least partly mediated through NMDA receptors participation. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. 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.

  6. 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

  7. Novel lipidized analogs of prolactin-releasing peptide have prolonged half-lives and exert anti-obesity effects after peripheral administration

    Czech Academy of Sciences Publication Activity Database

    Maletínská, L.; Nagelová, V.; Tichá, A.; Zemenová, J.; Pirník, Z.; Holubová, M.; Špolcová, A.; Mikulášková, Barbora; Blechová, M.; Sýkora, D.; Lacinová, Z.; Haluzík, M.; Železná, B.; Kuneš, Jaroslav

    2015-01-01

    Roč. 39, č. 6 (2015), s. 986-993 ISSN 0307-0565 R&D Projects: GA TA ČR(CZ) TE01020028 Institutional support: RVO:67985823 Keywords : food intake * prolactin-releasing peptide * GPR10 receptor Subject RIV: CE - Biochemistry Impact factor: 5.337, year: 2015

  8. Carboxypeptidase-D is elevated in prostate cancer and its anti-apoptotic activity is abolished by combined androgen and prolactin receptor targeting.

    Science.gov (United States)

    Thomas, Lynn N; Merrimen, Jennifer; Bell, David G; Rendon, Ricardo; Goffin, Vincent; Too, Catherine K L

    2014-05-01

    Carboxypeptidase-D (CPD) cleaves C-terminal arginine for nitric oxide (NO) production. CPD and NO levels are upregulated by testosterone (T) and prolactin (PRL) to promote survival of prostate cancer (pCa) cells. This study evaluated CPD immunostaining and T/PRL regulation of CPD and NO levels in benign and malignant prostate tissues/cells to determine the role of CPD in pCa. Immunohistochemistry (IHC) and tissue microarrays (TMA) were used to determine CPD immunostaining in prostate specimens. QPCR and immunoblotting were used to quantify CPD mRNA/protein expression in prostate cells. NO production was measured using 4,5-diaminofluorescein diacetate assay. CPD staining increased from 8.9 ± 3.8% (Mean ± SEM, n = 15) of benign epithelial cell area to 30.9 ± 2.9% (n = 30) of tumor cell area in one set of TMAs (P = 0.0008) and from 5.9 ± 0.9% (n = 45) of benign epithelial cell area to 18.8 ± 1.9% (n = 55) of tumor area in another (P prostate tissues (≥50 mm(2)) confirmed increased CPD staining, from 13.1 ± 2.9% in benign (n = 16) to 29.5 ± 4.4% in pCa (n = 31, P = 0.0095). T and/or PRL increased CPD expression in several pCa but not benign cell lines. T and PRL acted synergistically to increase NO production, which was abolished only when receptor antagonists flutamide and Δ1-9-G129R-hPRL were used together. CPD immunostaining and T/PRL-stimulated CPD expression were higher in pCa than benign tissues/cells. Elevated CPD increased NO production, which was abolished when both AR and PRLR were inhibited. Our study implicates a critical role for the T/PRL-stimulated CPD-Arg-NO pathway in pCa progression, and suggests that AR+PRLR inhibition is a more effective treatment for pCa. © 2014 Wiley Periodicals, Inc.

  9. Evaluation of the human prolactin of National Production for use in radioimmunoassay (RIA)

    International Nuclear Information System (INIS)

    Caso, R.; Arranz, C.

    1996-01-01

    In this work was studied the possibility of using the Prolactin hormone as raw material to produce Kits-RIA of Prolactin. Was used the prolactin, which is obtained in Cuba by the Pharmaceutical Institute Mario Munoz. Was made the labbeling of Prolactin with I-125, was used the hormone as standard and were done the probes of quality control. The Prolactin Hormone had the necesary quality to produce Kits-RIA-Prolactin

  10. Combinatorial assembly of small molecules into bivalent antagonists of TrkC or TrkA receptors.

    Directory of Open Access Journals (Sweden)

    Fouad Brahimi

    Full Text Available A library of peptidomimetics was assembled combinatorially into dimers on a triazine-based core. The pharmacophore corresponds to β-turns of the neurotrophin polypeptides neurotrophin-3 (NT-3, nerve growth factor (NGF, or brain-derived neurotrophic factor (BDNF. These are the natural ligands for TrkC, TrkA, and TrkB receptors, respectively. The linker length and the side-chain orientation of each monomer within the bivalent mimics were systematically altered, and the impact of these changes on the function of each ligand was evaluated. While the monovalent peptidomimetics had no detectable binding or bioactivity, four bivalent peptidomimetics (2c, 2d, 2e, 3f are selective TrkC ligands with antagonistic activity, and two bivalent peptidomimetics (1a, 1b are TrkC and TrkA ligands with antagonistic activity. All these bivalent compounds block ligand-dependent receptor activation and cell survival, without affecting neuritogenic differentiation. This work adds to our understanding of how the neurotrophins function through Trk receptors, and demonstrates that peptidomimetics can be designed to selectively disturb specific biological signals, and may be used as pharmacological probes or as therapeutic leads. The concept of altering side-chain, linker length, and sequence orientation of a subunit within a pharmacophore provides an easy modular approach to generate larger libraries with diversified bioactivity.

  11. Effects of mecamylamine (a nicotinic receptor antagonist on harman induced-amnesia in an inhibitory avoidance test

    Directory of Open Access Journals (Sweden)

    Mohammad Nasehi

    2011-10-01

    Full Text Available Introduction: β-carbolines alkaloids suchv as harmane have been found in common plant-derived foodstuffs (wheat, rice, corn, barley, grape and mushrooms. These alkaloids have many cognitive effects including alteration short and long term memory. In the present study, the effect of intra-CA1 injection of the nicotinic receptor antagonist mecamylamine on amnesia induced by harmane was examined in mice. Materials and Methods: Mice were bilaterally implanted with chronic cannulae in the CA1 regions of the dorsal hippocampus. One week after cannulae implantation, mice were trained in a step-down type inhibitory avoidance task, and were tested 24 h after training to measure step-down latency as a scale of memory. Results: Pre-training or post-training systemic injection of harmane induced amnesia. Pre-testing intra-dorsal hippocampus administration of the high dose of nicotinic receptor antagonist, mecamylamine (4 µg/mice also induced amnesia. On the other hand, pre-test intra-CA1 injection of ineffective doses of mecamylamine (0.5, 1 and 2 µg/mice fully restored harmane induced amnesia. Conclusion: The present finding in this study indicated that a complex interaction exists between nicotinic receptor of dorsal hippocampus and amnesia induced by Harmane.

  12. 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.

  13. Homologous radioimmunoassay for canine prolactin and its application in various physiological states

    International Nuclear Information System (INIS)

    Graef, K.-J.; Friedreich, E.; Matthes, S.; Hasan, S.H.

    1977-01-01

    The purification of canine prolactin and the development of an homologous radioimmunoassay including several physiological studies in the Beagle dog are described. The assay measured immunoreactive canine prolactin with a sensitivity limit of 0.6 ng/ml. Purified canine luteinizing hormone gave no significant inhibition in the assay whereas purified canine growth hormone inhibited the binding of 125 I-labelled canine prolactin to antiserum only at very high dose levels. In Beagle dogs, basal serum prolactin concentrations were in the range 1 to 2 ng/ml in normal male, normal female (metoestrus and anoestrus) and oophorectomized-hysterectomized female dogs. The prolactin concentration in one sample of amniotic fluid was in the same range, while in hypophysectomized make dogs no serum prolactin could be detected by the assay system. Serum prolactin concentrations tended to increase during late pregnancy and parturition, remaining high during the first 9 days of lactation. In consequence, a negative correlation was suggested between serum prolactin and serum progesterone concentrations. (author)

  14. Effects of cannabinoid CB1 receptor antagonist rimonabant in consolidation and reconsolidation of methamphetamine reward memory in mice.

    Science.gov (United States)

    Yu, Lu-lu; Wang, Xue-yi; Zhao, Mei; Liu, Yu; Li, Yan-qin; Li, Fang-qiong; Wang, Xiaoyi; Xue, Yan-xue; Lu, Lin

    2009-06-01

    Previous studies have shown that cannabinoid CB1 receptors play an important role in specific aspects of learning and memory, yet there has been no systematic study focusing on the involvement of cannabinoid CB1 receptors in methamphetamine-related reward memory. The purpose of this study was to examine whether rimonabant, a cannabinoid CB1 receptor antagonist, would disrupt the consolidation and reconsolidation of methamphetamine-related reward memory, using conditioned place preference paradigm (CPP). Separate groups of male Kunming mice were trained to acquire methamphetamine CPP. Vehicle or rimonabant (1 mg/kg or 3 mg/kg, i.p.) was given at different time points: immediately after each CPP training session (consolidation), 30 min before the reactivation of CPP (retrieval), or immediately after the reactivation of CPP (reconsolidation). Methamphetamine CPP was retested 24 h and 1 and 2 weeks after rimonabant administration. Rimonabant at doses of 1 and 3 mg/kg significantly inhibited the consolidation of methamphetamine CPP. Only high-dose rimonabant (3 mg/kg) disrupted the retrieval and reconsolidation of methamphetamine CPP. Rimonabant had no effect on methamphetamine CPP in the absence of methamphetamine CPP reactivation. Our findings suggest that cannabinoid CB1 receptors play a major role in methamphetamine reward memory, and cannabinoid CB1 receptor antagonists may be a potential pharmacotherapy to manage relapse associated with drug-reward-related memory.

  15. 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.

  16. 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

  17. [3H]AVP binding to rat renal tubular receptors during long-term treatment with an antagonist of arginine vasopressin

    International Nuclear Information System (INIS)

    Mah, S.C.; Whitebread, S.E.; De Gasparo, M.; Hofbauer, K.G.

    1988-01-01

    The interaction of an antagonist of arginine vasopressin (AVP), d(CH2)5-D-Tyr(Et)VAVP, with renal tubular V2 receptors were studied in medullary membrane preparations from kidneys of Sprague-Dawley and Brattleboro rats. In both rat strains, V2 receptors had comparable KD and Bmax values for binding of [3H]AVP. In vitro studies revealed that the V2-antagonist was more potent than cold AVP in displacing [3H]AVP. In vivo treatment of Sprague-Dawley rats with the antagonist over one week resulted only in a transient state of diabetes insipidus (DI). No specific [3H]AVP binding was detectable throughout the period of administration. Chronic treatment of Brattleboro rats resulted in a complete normalization of water intake. This agonistic effect was also associated with undetectable [3H]AVP binding. After stopping the infusion of d(CH2)5-D-Tyr(Et)VAVP, Bmax values tended to rise but had still not reached base line values after 6 days. In contrast, the chronic infusion of AVP in Brattleboro rats resulted in a reduction in water intake which was accompanied by a decreased Bmax. [3H]AVP binding remained detectable during the entire treatment period. Thereafter Bmax was restored to base line values within 2 days of stopping the infusion. These results suggest that d(CH2)5-D-Tyr(Et)VAVP has a high affinity for V2 receptors in both Sprague-Dawley and Brattleboro rats. Its rate of dissociation from the receptor appears to be much slower than that of AVP. In Brattleboro rats, the binding of d(CH2)5-D-Tyr(Et)VAVP leads to an antidiuretic response. In Sprague-Dawley rats, a transient diuretic response is followed by a progressive normalization in water intake. This occurs despite persistent and complete blockade of renal medullary V2 receptors

  18. Interactions of CB1 and mGlu5 receptor antagonists in food intake, anxiety and memory models in rats.

    Science.gov (United States)

    Varga, Balázs; Kassai, Ferenc; Gyertyán, István

    2012-12-01

    CB(1) receptor antagonists proved to be effective anti-obesity drugs, however, their depressive and anxiogenic effects became also evident. Finding solution to overcome these psychiatric side effects is still in focus of research. Based on the available clinical and preclinical results we hypothesized that the combination of CB(1) and mGlu(5) receptor antagonisms may result in a pharmacological intervention, where the anxiolytic mGlu(5) receptor inhibition may counteract the anxiogenic psychiatric side effects of CB(1) antagonism, while CB(1) antagonism may ameliorate the memory impairing effect of mGlu(5) receptor antagonism. Further, the two components will synergistically interact in blocking food-intake and reducing obesity. For testing the interaction of mGlu(5) and CB(1) receptor antagonism MTEP [3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pridine; SIB-1757, 6-methyl-2-(phenylazo)-3-pyridinol)] (mGlu(5) antagonist) and rimonabant [(5-(4-Chlorophenyl)-1-(2,4-dichloro-phenyl)-4-methyl-N-(piperidin-1-yl)-1H-pyrazole-3-carboxamide)hydrochloride] (CB(1) antagonist) were used. All experiments were carried out in rats. Effects of the compounds on anxiety were tested in two foot shock induced ultrasonic vocalization paradigms, appetite suppression was assessed in the food intake test, while memory effects were tested in a context conditioned ultrasonic vocalization setup. MTEP abolished the anxiogenic effect of rimonabant, while there was an additive cooperation in suppressing appetite. However, rimonabant did not ameliorate the memory impairing effect of MTEP. By combination of CB(1) and mGluR5 antagonism, anxiety related side effects might be attenuated, appetite suppression maintained, nevertheless, the possible emergence of unwanted memory impairments can overshadow its therapeutic success. Copyright © 2012 Elsevier Inc. All rights reserved.

  19. Casopitant: a novel NK(1)-receptor antagonist in the prevention of chemotherapy-induced nausea and vomiting

    DEFF Research Database (Denmark)

    Ruhlmann, Christina; Herrstedt, Jørn

    2009-01-01

    Chemotherapy-induced nausea and vomiting (CINV) are among the most feared and distressing symptoms experienced by patients with cancer. The knowledge of the pathogenesis and neuropharmacology of CINV has expanded enormously over the last decades, the most significant discoveries being the role of 5......-hydroxytryptamine (5-HT)(3)- and neurokinin (NK)(1) receptors in the emetic reflex arch. This has led to the development of two new classes of antiemetics acting as highly selective antagonists at one of these receptors. These drugs have had a huge impact in the protection from chemotherapy-induced vomiting...

  20. 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...

  1. Development and characterization of a homologous radioimmunoassay for equine prolactin

    International Nuclear Information System (INIS)

    Roser, J.F.; Chang, Y.S.; Papkoff, H.; Li, C.H.

    1984-01-01

    A specific and sensitive homologous radioimmunoassay has been developed for equine prolactin, suitable for measuring prolactin concentrations in serum of horses. The sensitivity of the assay ranged from 0.4 to 0.6 ng/ml and the intra- and inter-assay coefficients of variation averaged 6.9 and 15.4%, respectively, for five doses of hormone. Cross-reactivity with other mammalian and nonmammalian prolactins and growth hormones was less than 20 and 0.3%, respectively. Cross-reactivity with equine growth hormone was less than 0.07%. Equine serum and pituitary extracts showed parallel dilution-response curves with equine prolactin. The percentage recovery of exogenous equine prolactin in serum was 89%. Preliminary analysis of several physiological samples (stallions, pregnant, and nonpregnant mares) yielded values from 0.6 to 12.0 ng/ml

  2. QSAR study on the histamine (H3 receptor antagonists using the genetic algorithm: Multi parameter linear regression

    Directory of Open Access Journals (Sweden)

    Adimi Maryam

    2012-01-01

    Full Text Available A quantitative structure activity relationship (QSAR model has been produced for predicting antagonist potency of biphenyl derivatives as human histamine (H3 receptors. The molecular structures of the compounds are numerically represented by various kinds of molecular descriptors. The whole data set was divided into training and test sets. Genetic algorithm based multiple linear regression is used to select most statistically effective descriptors. The final QSAR model (N =24, R2=0.916, F = 51.771, Q2 LOO = 0.872, Q2 LGO = 0.847, Q2 BOOT = 0.857 was fully validated employing leaveone- out (LOO cross-validation approach, Fischer statistics (F, Yrandomisation test, and predictions based on the test data set. The test set presented an external prediction power of R2 test=0.855. In conclusion, the QSAR model generated can be used as a valuable tool for designing similar groups of new antagonists of histamine (H3 receptors.

  3. 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

  4. Tritium labelling and characterization of the potent imidazoline I1 receptor antagonist [5,7-{sup 3}H] ({+-})-efaroxan at high specific activity

    Energy Technology Data Exchange (ETDEWEB)

    Egan, J.A.; Filer, C.N. E-mail: crist.filer@perkinelmer.com

    2003-06-01

    ({+-})-Efaroxan 1 is a selective antagonist at the imidazoline I1 receptor. [{sup 3}H] ({+-})-Efaroxan was required to explore its mechanism of action via receptor binding assay, and the radioligand was prepared by means of catalytic dehalogenation of a dibrominated precursor with tritium.

  5. Transfer of milk prolactin ro the plasma of neonatal rats by intestinal absorption

    Energy Technology Data Exchange (ETDEWEB)

    Whitworth, N S; Grosvenor, C E [Tennessee Univ., Memphis (USA). Dept. of Physiology and Biophysics

    1978-11-01

    Prolactin passes from the systemic circulation of lactating rats into the milk where it can be consumed by the young rats during suckling. /sup 131/- labelled rat prolactin was detected in the plasma of 9- to 14-day-old rats after being nursed by mothers previously injected with /sup 131/I-labelled rat prolactin and after the pups had received /sup 131/I-labelled rat prolactin by gastric intubation. It was estimated that 16% of the /sup 131/I-labelled rat prolactin given by gastric intubation subsequently appeared in the plasma of the neonate. Gastric administration of 10.5 or 21.0 ..mu..g B-1 rat prolactin significantly raised the level of prolactin in the plasma of 13-day-old pups, but a similar increase was not observed when 27-day-old rats were given 46.2 ..mu..g B-1 prolactin by gastric intubation. The concentration of prolactin in the plasma of 13-to 14-day-old rats rose to 55 ng/ml 30 min after the onset of nursing by mothers whose mammary glands were full of milk, whereas the concentration in the plasma of mothers with empty mammary glands remained at basal values. It is concluded that the intestine of the newborn is permeable to prolactin and that milk may constitute an exogeneous source of prolactin for the suckled offspring.

  6. The IL-6 receptor super-antagonist Sant7 enhances antiproliferative and apoptotic effects induced by dexamethasone and zoledronic acid on multiple myeloma cells.

    Science.gov (United States)

    Tassone, Pierfrancesco; Galea, Eulalia; Forciniti, Samantha; Tagliaferri, Pierosandro; Venuta, Salvatore

    2002-10-01

    Interleukin-6 (IL-6) is the major growth and survival factor for multiple myeloma (MM), and has been shown to protect MM cells from apoptosis induced by a variety of agents. IL-6 receptor antagonists, which prevent the assembly of functional IL-6 receptor complexes, inhibit cell proliferation and induce apoptosis in MM cells. We have investigated whether the IL-6 receptor super-antagonist Sant7 might enhance the antiproliferative and apoptotic effects induced by the combination of dexamethasone (Dex) and zoledronic acid (Zln) on human MM cell lines and primary cells from MM patients. Here we show that each of these compounds individually induced detectable antiproliferative effects on MM cells. Sant7 significantly enhanced growth inhibition and apoptosis induced by Dex and Zln on both MM cell lines and primary MM cells. These results indicate that overcoming IL-6 mediated cell resistance by Sant7 potentiates the effect of glucocorticoides and bisphosphonates on MM cell growth and survival, providing a rationale for therapies including IL-6 antagonists in MM.

  7. Does alpha 1-acid glycoprotein act as a non-functional receptor for alpha 1-adrenergic antagonists?

    Science.gov (United States)

    Qin, M; Oie, S

    1994-11-01

    The ability of a variety of alpha 1-acid glycoproteins (AAG) to affect the intrinsic activity of the alpha 1-adrenergic antagonist prazosin was studied in rabbit aortic strip preparations. From these studies, the activity of AAG appears to be linked to their ability to bind the antagonist. However, a capability to bind prazosin was not the only requirement for this effect. The removal of sialic acid and partial removal of the galactose and mannose residues by periodate oxidation of human AAG all but eliminated the ability of AAG to affect the intrinsic pharmacologic activity of prazosin, although the binding of prazosin was not significantly affected. The presence of bovine AAG, a protein that has a low ability to bind prazosin, reduced the effect of human AAG on prazosin activity. Based upon these results, we propose that AAG is able to bind in the vicinity of the alpha 1-adrenoceptors, therefore extending the binding region for antagonists in such a way as to decrease the ability of the antagonist to interact with the receptor. The carbohydrate side-chains are important for the binding of AAG in the region of the adrenoceptor.

  8. Naloxone : actions of an antagonist

    NARCIS (Netherlands)

    Dorp, Eveline Louise Arianna van

    2009-01-01

    The opioid antagonist naloxone has a special place in pharmacology – it has no intrinsic action of its own, but it is able to save lives in the case of life threatening side-effects caused by other drugs. Naloxone is an antagonist for all opioid receptors, but most specifically for the μ-opioid

  9. The Three Dimensional Quantitative Structure Activity Relationships (3D-QSAR and Docking Studies of Curcumin Derivatives as Androgen Receptor Antagonists

    Directory of Open Access Journals (Sweden)

    Jing Yang

    2012-05-01

    Full Text Available Androgen receptor antagonists have been proved to be effective anti-prostate cancer agents. 3D-QSAR and Molecular docking methods were performed on curcumin derivatives as androgen receptor antagonists. The bioactive conformation was explored by docking the potent compound 29 into the binding site of AR. The constructed Comparative Molecular Field Analysis (CoMFA and Comparative Similarity Indices Analysis (CoMSIA models produced statistically significant results with the cross-validated correlation coefficients q2 of 0.658 and 0.567, non-cross-validated correlation coefficients r2 of 0.988 and 0.978, and predicted correction coefficients r2pred of 0.715 and 0.793, respectively. These results ensure the CoMFA and CoMSIA models as a tool to guide the design of novel potent AR antagonists. A set of 30 new analogs were proposed by utilizing the results revealed in the present study, and were predicted with potential activities in the developed models.

  10. 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

  11. 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

  12. Molecular sampling of the allosteric binding pocket of the TSH receptor provides discriminative pharmacophores for antagonist and agonists.

    Science.gov (United States)

    Hoyer, Inna; Haas, Ann-Karin; Kreuchwig, Annika; Schülein, Ralf; Krause, Gerd

    2013-02-01

    The TSHR (thyrotropin receptor) is activated endogenously by the large hormone thyrotropin and activated pathologically by auto-antibodies. Both activate and bind at the extracellular domain. Recently, SMLs (small-molecule ligands) have been identified, which bind in an allosteric binding pocket within the transmembrane domain. Modelling driven site-directed mutagenesis of amino acids lining this pocket led to the delineation of activation and inactivation sensitive residues. Modified residues showing CAMs (constitutively activating mutations) indicate signalling-sensitive positions and mark potential trigger points for agonists. Silencing mutations lead to an impairment of basal activity and mark contact points for antagonists. Mapping these residues on to a structural model of TSHR indicates locations where an SML may switch the receptor to an inactive or active conformation. In the present article, we report the effects of SMLs on these signalling-sensitive amino acids at the TSHR. Surprisingly, the antagonistic effect of SML compound 52 was reversed to an agonistic effect, when tested at the CAM Y667A. Switching agonism to antagonism and the reverse by changing either SMLs or residues covering the binding pocket provides detailed knowledge about discriminative pharmacophores. It prepares the basis for rational optimization of new high-affinity antagonists to interfere with the pathogenic activation of the TSHR.

  13. A DFT approach to discriminate the antagonist and partial agonist activity of ligands binding to the NMDA receptor

    Science.gov (United States)

    Haslak, Zeynep Pinar; Bozkurt, Esra; Dutagaci, Bercem; De Proft, Frank; Aviyente, Viktorya; De Vleeschouwer, Freija

    2018-02-01

    The activation of N-methyl-D-aspartate receptors is found to be intimately associated with neurodegenerative diseases which make them promising therapeutic targets. Despite the significantly increasing multidisciplinary interests centred on this ionotropic channel, design of new ligands with intended functional activity remains a great challenge. In this article, a computational study based on density functional theory is presented to understand the structural factors of ligands determining their function as antagonists and partial agonists. With this aim, the GluN1 subunit is chosen as being one of the essential components in the activation mechanism, and quantum chemical calculations are implemented for 30 antagonists and 30 partial agonists known to bind to this subunit with different binding affinities. Several quantum chemical descriptors are investigated which might unlock the difference between antagonists and partial agonists.

  14. Pubertal dependent effects of cadmium on episodic prolactin secretion in male rats

    Energy Technology Data Exchange (ETDEWEB)

    Lafuente, A.; Alvarez-Demanuel, E.; Marquez, N. [Fac. de Cienicas, Orense (Spain). Lab. de Toxicologia; Esquifino, A.I. [Dept. Bioquimica, Facultad de Medicina, Universidad Complutense, 28040-Madrid (Spain)

    1999-02-01

    This work was undertaken to assess if exposure to cadmium related to puberty may affect the episodic pattern of prolactin. Male rats were submitted to cadmium exposure, from day 30 to 60 or from day 60 to 90 of life respectively, at a dose of 50 ppm in the drinking water. Control age-matched rats received cadmium-free water. Prepubertal cadmium administration decreased mean serum prolactin levels and the absolute amplitude of the prolactin pulses. Subchronic exposure to cadmium of adult rats decreased mean serum prolactin levels, the absolute amplitude of the prolactin pulses and their duration, and the mean half-life of the hormone. These results suggest that subchronic cadmium exposure changes the secretory pattern of prolactin in adult male rats in a puberty-dependent way. (orig.) With 1 fig., 1 tab., 37 refs.

  15. 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)

  16. The Effect of Sympathetic Antagonists on the Antidepressant Action of Alprazolam

    Directory of Open Access Journals (Sweden)

    Gorash ZM

    2008-01-01

    Full Text Available Alprazolam is an anti-anxiety drug shown to be effective in the treatment of depression. In this study, the effect of sympathetic receptor antagonists on alprazolam–induced antidepressant action was studied using a mouse model of forced swimming behavioral despair. The interaction of three sympathetic receptor antagonists with benzodiazepines, which may impact the clinical use of alprazolam, was also studied. Behavioral despair was examined in six groups of albino mice. Drugs were administered intraperitoneally. The control group received only a single dose of 1% Tween 80. The second group received a single dose of alprazolam, and the third group received an antagonist followed by alprazolam. The fourth group was treated with imipramine, and the fifth group received an antagonist followed by imipramine. The sixth group was treated with a single dose of an antagonist alone (atenolol, a β1-selective adrenoceptor antagonist; propranolol, a non selective β-adrenoceptor antagonist; and prazocin, an α1-adrenoceptor antagonist. Results confirmed the antidepressant action of alprazolam and imipramine. Prazocin treatment alone produced depression, but it significantly potentiated the antidepressant actions of imipramine and alprazolam. Atenolol alone produced an antidepressant effect and potentiated the antidepressant action of alprazolam. Propranolol treatment alone produced depression, and antagonized the effects of alprazolam and imipramine, even producing depression in combined treatments. In conclusion, our results reveal that alprazolam may produce antidepressant effects through the release of noradrenaline, which stimulates β2 receptors to produce an antidepressant action. Imipramine may act by activating β2 receptors by blocking or down-regulating β1 receptors.

  17. A peptide antagonist of the ErbB1 receptor inhibits receptor activation, tumor cell growth and migration in vitro and xenograft tumor growth in vivo

    DEFF Research Database (Denmark)

    Xu, Ruodan; Povlsen, Gro Klitgaard; Soroka, Vladislav

    2010-01-01

    The epidermal growth factor family of receptor tyrosine kinases (ErbBs) plays essential roles in tumorigenesis and cancer disease progression, and therefore has become an attractive target for structure-based drug design. ErbB receptors are activated by ligand-induced homo- and heterodimerization...... constitutes part of the dimerization arm of ErbB3. Inherbin3 binds to the extracellular domains of all four ErbB receptors, with the lowest peptide binding affinity for ErbB4. Inherbin3 functions as an antagonist of epidermal growth factor (EGF)-ErbB1 signaling. We show that Inherbin3 inhibits EGF-induced Erb....... Structural studies have revealed that ErbB receptor dimers are stabilized by receptor-receptor interactions, primarily mediated by a region in the second extracellular domain, termed the "dimerization arm". The present study is the first biological characterization of a peptide, termed Inherbin3, which...

  18. Primary Hypothyroidism with Exceptionally High Prolactin-A Really Big Deal.

    Science.gov (United States)

    Khorassanizadeh, Rahim; Sundaresh, Vishnu; Levine, Steven N

    2016-07-01

    Primary hypothyroidism can cause both hyperprolactinemia and pituitary hyperplasia. The degree of hyperprolactinemia is generally modest, and rarely do prolactin concentrations exceed 100 ng/mL (4.34 nmol/L). This combination of hyperprolactinemia and pituitary gland enlargement might raise suspicion for a prolactinoma or a nonfunctioning adenoma limiting the ability of hypothalamic dopamine to inhibit prolactin production, the so-called "stalk effect." We describe a 30-year-old female with headaches, galactorrhea, and hyperprolactinemia with a presumptive diagnosis of a prolactinoma. She had hypothyroidism after treatment of Graves disease at age 17 years but was noncompliant with levothyroxine replacement. Thyroid-stimulating hormone (TSH) was 263 mIU/L, FT4 was 3.01 pmol/L, and prolactin was 323 ng/mL (14.06 nmol/L). Magnetic resonance imaging (MRI) demonstrated increased volume of the pituitary gland with homogeneous enhancement with gadolinium. Levothyroxine treatment for 2 weeks decreased her TSH to130 mIU/L, but her total prolactin remained elevated at 386 ng/mL (16.78 nmol/L). Further testing identified that 76% of the total prolactin was macroprolactin. Primary hypothyroidism can cause hyperprolactinemia, and prolonged disease may lead to pituitary hyperplasia. However, a marked elevation of prolactin should raise suspicion to investigate additional etiologies for hyperprolactinemia. Our case exemplifies a dual etiology for hyperprolactinemia and pituitary hyperplasia caused by both hypothyroidism and macroprolactin. This knowledge is invaluable for clinicians to avoid unnecessary management with dopamine agonists and/or surgery. This patient's prolactin was 323 ng/mL (14.06 nmol/L). Before our case, the highest prolactin in a hypothyroid patient reported in the literature was 253 ng/mL (11.0 nmol/L). Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Receptor-mediated mechanism for the transport of prolactin from blood to cerebrospinal fluid

    International Nuclear Information System (INIS)

    Walsh, R.J.; Slaby, F.J.; Posner, B.I.

    1987-01-01

    Prolactin (PRL) interacts with areas of the central nervous system which reside behind the blood-brain barrier. While vascular PRL does not cross this barrier, it is readily accessible to the cerebrospinal fluid (CSF) from which it may gain access to the PRL-responsive areas of the brain. Studies were undertaken to characterize the mechanism responsible for the translocation of PRL from blood to CSF. Rats were given external jugular vein injections of [ 125 -I]iodo-PRL in the presence or absence of an excess of unlabeled ovine PRL (oPRL), human GH, bovine GH, or porcine insulin. CSF and choroid plexus were removed 60 min later. CSF samples were electrophoresed on sodium dodecyl sulfate-polyacrylamide slab gels and resultant autoradiographs were analyzed with quantitative microdensitometry. The data revealed that unlabeled lactogenic hormones, viz. oPRL and human GH, caused a statistically significant inhibition of [ 125 I]iodo-PRL transport from blood to CSF. In contrast, nonlactogenic hormones, viz bovine GH and insulin, had no effect on [ 125 I]iodo-PRL transport into the CSF. An identical pattern of competition was observed in the binding of hormone to the choroid plexus. Furthermore, vascular injections of [ 125 I]iodo-PRL administered with a range of concentrations of unlabeled oPRL revealed a dose-response inhibition in the transport of [ 125 I]iodo-PRL from blood to CSF. The study demonstrates that PRL enters the CSF by a specific, PRL receptor-mediated transport mechanism. The data is consistent with the hypothesis that the transport mechanism resides at the choroid plexus. The existence of this transport mechanism reflects the importance of the cerebroventricular system in PRL-brain interactions

  20. EFFECT OF ADRENALECTOMY ON PROLACTIN SECRETION IN PRIMIPAROUS AND MULTIPAROUS LACTATING RATS

    Directory of Open Access Journals (Sweden)

    C. D. C. Sanches

    2018-04-01

    Full Text Available The adenohypophysis produces among other hormones prolactin, which plays an important role in reproduction, especially on the mammary glands and lactation of mammals. Prolactin is tonically controlled by tufo-infundibular dopamine, but several studies indicate that prolactin secretion is altered by the action of glucocorticoids and, therefore, is related to stress. However, the exact contribution of corticosteroids in the control of prolactin secretion is poorly understood. On the other hand, it is also known that reproductive experience can modify prolactin secretion by adenohypophysis. Thus, the present study aims to study the hormonal relationships of the hypothalamic-pituitary-adrenal axis, in particular, the glucocorticoid relationship on prolactin secretion as a function of the reproductive experience in females during lactation. The results show that reproductive experience may be a factor modifying the sensitivity of the neuroendocrine response of prolactin secretion to glucocorticoids. However, more studies are needed to understand the possible mechanisms involved, as well as possible modifications in this response as a function of the reproductive status of the females.

  1. 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.

  2. Discovery of Indazoles as Potent, Orally Active Dual Neurokinin 1 Receptor Antagonists and Serotonin Transporter Inhibitors for the Treatment of Depression.

    Science.gov (United States)

    Degnan, Andrew P; Tora, George O; Huang, Hong; Conlon, David A; Davis, Carl D; Hanumegowda, Umesh M; Hou, Xiaoping; Hsiao, Yi; Hu, Joanna; Krause, Rudolph; Li, Yu-Wen; Newton, Amy E; Pieschl, Rick L; Raybon, Joseph; Rosner, Thorsten; Sun, Jung-Hui; Taber, Matthew T; Taylor, Sarah J; Wong, Michael K; Zhang, Huiping; Lodge, Nicholas J; Bronson, Joanne J; Macor, John E; Gillman, Kevin W

    2016-12-21

    Combination studies of neurokinin 1 (NK1) receptor antagonists and serotonin-selective reuptake inhibitors (SSRIs) have shown promise in preclinical models of depression. Such a combination may offer important advantages over the current standard of care. Herein we describe the discovery and optimization of an indazole-based chemotype to provide a series of potent dual NK1 receptor antagonists/serotonin transporter (SERT) inhibitors to overcome issues of ion channel blockade. This effort culminated in the identification of compound 9, an analogue that demonstrated favorable oral bioavailability, excellent brain uptake, and robust in vivo efficacy in a validated depression model. Over the course of this work, a novel heterocycle-directed asymmetric hydrogenation was developed to facilitate installation of the key stereogenic center.

  3. Immunological properties of prolactin and studies on a gonadotropin binding inhibitor

    International Nuclear Information System (INIS)

    Chang, Y.S.

    1985-01-01

    The physiological role of prolactin in horses has not yet been well defined. With the availability of highly purified ePRL for inducing antibody formation in rabbits and for radiolabeling with Na 125 I, a very sensitive (0.4-0.6 ng/ml) and highly specific homologous RIA for ePRL was developed. A heterologous RIA using 125 I-labeled ovine PRL and anti-ePRL antiserum was also developed and compared to the homologous RIA for ePRL. Of the two systems, it is concluded that this homologous RIA system is more suitable and more reliable for measuring prolactin concentration in horse serum samples. Until now, biochemical information on PRL has not been available for reptilian species. Sea turtle (Chelonia mydas) prolactin was purified from pituitary extracts by selective precipitation, DEAE-cellulose chromatography and gel filtration. Similar to other species of PRL, sea turtle PRL is a 22,000-24,000 daltons protein and contains a high content of glutamic acid, aspartic acid, serine and leucine, the N-terminal amino acid residue. Gonadotropin (FSH) binding inhibitor was partially purified from sheep testes by ammonium sulfate fractionation and ion exchange chromatography. The FSH-BI (molecular weight: 50,000 daltons, estimated by gel filtration) contains a protein moiety necessary for binding inhibitory activity. The inhibition of the binding of 125 I-labeled ovine FSH to its receptor by the FSH-BI is not competitive. Both in vivo and in vitro biological studies of FSH-BI preparations in rats indicated various effects on FSH and LH activities at the gonadal level. These findings suggest a physiological role for FSH-BI in the regulation of reproduction

  4. Variation in prolactin is related to variation in sexual behavior and contact affiliation.

    Directory of Open Access Journals (Sweden)

    Charles T Snowdon

    Full Text Available Prolactin is associated with both maternal and paternal care and appears important in developing a bond between parent and infant. In contrast with oxytocin, another hormone important in infant care, there is scant information on the role of prolactin in maintaining adult heterosexual relationships. We present here the first results demonstrating a relationship between prolactin levels and sexual and contact affiliation behavior in a pair-bonded species. We studied cotton-top tamarins, a socially-monogamous, cooperatively-breeding primate. We measured chronic urinary prolactin levels over a four week period to include the entire female ovulatory cycle and correlated prolactin levels in males and females with simultaneous measures of contact affiliation and sexual behavior. Current mothers who were no longer nursing displayed lower amounts of sexual behavior and proximity than non-breeding females and also had marginally lower levels of prolactin. The prolactin levels of males and females were similar within pairs, and variation in prolactin levels for both sexes was explained both by the amount of sexual behavior and contact affiliation. The results parallel a previous study that compared oxytocin levels with sociosexual behavior in the same species, and supports the hypothesis that both prolactin and oxytocin are involved in pair-bonding as well as in infant care.

  5. Effect of THIP and SL 76002, two clinically experimented GABA-mimetic compounds, on anterior pituitary GABA receptors and prolactin secretion in the rat

    International Nuclear Information System (INIS)

    Apud, J.A.; Masotto, C.; Racagni, G.

    1987-01-01

    In the present study, the ability of three direct GABA agonists, muscimol, THIP and SL 76002 to displace 3 H-GABA binding from anterior pituitary and medio-basal hypothalamus membranes was evaluated. Further, the effect of both THIP and SL 76002 on baseline prolactin levels or after stimulation of hormone release with haloperidol has been also studied. Either muscimol, THIP or SL 76002 have shown to posses 7-, 7- and 3-fold higher affinity, respectively, for the central nervous system than for the anterior pituitary 3 H-GABA binding sites. Moreover, THIP and SL 76002 have demonstrated to be respectively, 25- and 1000- fold less potent than muscimol in inhibiting 3 H- GABA binding at the level of the anterior pituitary and about 25- and 2700-fold less potent at the level of the medio-basal hypothalamus. Under basal conditions, either THIP or SL 76002 were ineffective to reduce prolactin release. However, after stimulation of prolactin secretion through blockade of the dopaminergic neurotransmission with haloperidol (0.1 mg/kg), both THIP (10 mg/kg) and SL 76002 (200 mg/kg) significantly counteracted the neuroleptic-induced prolactin rise with a potency which is in line with their ability to inhibit 3 H-GABA binding in the anterior pituitary. The present results indicate that both compounds inhibit prolactin release under specific experimental situations probably through a GABAergic mechanism. In view of the endocrine effects of these GABA-mimetic compounds, the possibility arises for an application of these type of drugs in clinical neuroendocrinology. 35 references, 3 figures, 2 tables

  6. Prolactin protects retinal pigment epithelium by inhibiting sirtuin 2-dependent cell death

    Directory of Open Access Journals (Sweden)

    Rodrigo Meléndez García

    2016-05-01

    Full Text Available The identification of pathways necessary for retinal pigment epithelium (RPE function is fundamental to uncover therapies for blindness. Prolactin (PRL receptors are expressed in the retina, but nothing is known about the role of PRL in RPE. Using the adult RPE 19 (ARPE-19 human cell line and mouse RPE, we identified the presence of PRL receptors and demonstrated that PRL is necessary for RPE cell survival via anti-apoptotic and antioxidant actions. PRL promotes the antioxidant capacity of ARPE-19 cells by reducing glutathione. It also blocks the hydrogen peroxide-induced increase in deacetylase sirtuin 2 (SIRT2 expression, which inhibits the TRPM2-mediated intracellular Ca2+ rise associated with reduced survival under oxidant conditions. RPE from PRL receptor-null (prlr−/− mice showed increased levels of oxidative stress, Sirt2 expression and apoptosis, effects that were exacerbated in animals with advancing age. These observations identify PRL as a regulator of RPE homeostasis.

  7. The effects of N-methyl D-aspartate and B-adrenergic receptor antagonists on the reconsolidation of reward memory: a meta-analysis.

    Science.gov (United States)

    Das, Ravi K; Freeman, Tom P; Kamboj, Sunjeev K

    2013-03-01

    Pharmacological memory reconsolidation blockade provides a potential mechanism for ameliorating the maladaptive reward memories underlying relapse in addiction. Two of the most promising classes of drug that interfere with reconsolidation and have translational potential for human use are N-methyl-D-aspartate receptor (NMDAR) and B-Adrenergic receptor (B-AR) antagonists. We used meta-analysis and meta-regression to assess the effects of these drugs on the reconsolidation of reward memory in preclinical models of addiction. Pharmacokinetic, mnemonic and methodological factors were assessed for their moderating impact on effect sizes. An analysis of 52 independent effect sizes (NMDAR=30, B-AR=22) found robust effects of both classes of drug on memory reconsolidation, but a far greater overall effect of NMDAR antagonism than B-AR antagonism. Significant moderating effects of drug dose, relapse process and primary reinforcer were found. The findings suggest that reward memory reconsolidation can be robustly targeted by NMDAR antagonists and to a lesser extent, by B-AR antagonists. Implications for future clinical work are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  8. Activation of protein kinase C inhibits synthesis and release of decidual prolactin

    International Nuclear Information System (INIS)

    Harman, I.; Costello, A.; Ganong, B.; Bell, R.M.; Handwerger, S.

    1986-01-01

    Activation of calcium-activated, phospholipid-dependent protein kinase C by diacylglycerol and phorbol esters has been shown to mediate release of hormones in many systems. To determine whether protein kinase C activation is also involved in the regulation of prolactin release from human decidual, the authors have examined the effects of various acylglycerols and phorbol esters on the synthesis and release of prolactin from cultured human decidual cells. sn-1,2-Dioctanolyglycerol (diC 8 ), which is known to stimulate protein kinase C in other systems, inhibited prolactin release in a dose-dependent manner with maximal inhibition of 53.1% at 100 μM. Diolein (100 μM), which also stimulates protein kinase C activity in some systems, inhibited prolactin release by 21.3%. Phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-didecanoate, and 4β-phorbol 12,13-dibutyrate, which activate protein kinase C in other systems, also inhibited the release of prolactin, which the protein kinase C inactivate 4α-phorbol-12,13-didecanoate was without effect. The inhibition of prolactin release was secondary to a decrease in prolactin synthesis. Although diC 8 and PMA inhibited the synthesis and release of prolactin, these agents had no effect on the synthesis or release of trichloroacetic acid-precipitable [ 35 S]methionine-labeled decidual proteins and did not cause the release of the cytosolic enzymes lactic dehydrogenase and alkaline phosphatase. DiC 8 and PMA stimulates the specific activity of protein kinase C in decidual tissue by 14.6 and 14.0-fold, respectively. The inhibition of the synthesis and release of prolactin by diC 8 and phorbol esters strongly implicates protein kinase C in the regulation of the production and release of prolactin from the decidua

  9. 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.

  10. Structure-based prediction of subtype selectivity of histamine H3 receptor selective antagonists in clinical trials.

    Science.gov (United States)

    Kim, Soo-Kyung; Fristrup, Peter; Abrol, Ravinder; Goddard, William A

    2011-12-27

    Histamine receptors (HRs) are excellent drug targets for the treatment of diseases, such as schizophrenia, psychosis, depression, migraine, allergies, asthma, ulcers, and hypertension. Among them, the human H(3) histamine receptor (hH(3)HR) antagonists have been proposed for specific therapeutic applications, including treatment of Alzheimer's disease, attention deficit hyperactivity disorder (ADHD), epilepsy, and obesity. However, many of these drug candidates cause undesired side effects through the cross-reactivity with other histamine receptor subtypes. In order to develop improved selectivity and activity for such treatments, it would be useful to have the three-dimensional structures for all four HRs. We report here the predicted structures of four HR subtypes (H(1), H(2), H(3), and H(4)) using the GEnSeMBLE (GPCR ensemble of structures in membrane bilayer environment) Monte Carlo protocol, sampling ∼35 million combinations of helix packings to predict the 10 most stable packings for each of the four subtypes. Then we used these 10 best protein structures with the DarwinDock Monte Carlo protocol to sample ∼50 000 × 10(20) poses to predict the optimum ligand-protein structures for various agonists and antagonists. We find that E206(5.46) contributes most in binding H(3) selective agonists (5, 6, 7) in agreement with experimental mutation studies. We also find that conserved E5.46/S5.43 in both of hH(3)HR and hH(4)HR are involved in H(3)/ H(4) subtype selectivity. In addition, we find that M378(6.55) in hH(3)HR provides additional hydrophobic interactions different from hH(4)HR (the corresponding amino acid of T323(6.55) in hH(4)HR) to provide additional subtype bias. From these studies, we developed a pharmacophore model based on our predictions for known hH(3)HR selective antagonists in clinical study [ABT-239 1, GSK-189,254 2, PF-3654746 3, and BF2.649 (tiprolisant) 4] that suggests critical selectivity directing elements are: the basic proton

  11. Structural basis of subunit selectivity for competitive NMDA receptor antagonists with preference for GluN2A over GluN2B subunits

    Energy Technology Data Exchange (ETDEWEB)

    Lind, Genevieve E.; Mou, Tung-Chung; Tamborini, Lucia; Pomper, Martin G.; De Micheli, Carlo; Conti, Paola; Pinto, Andrea; Hansen, Kasper B. (JHU); (Milan); (Montana)

    2017-07-31

    NMDA-type glutamate receptors are ligand-gated ion channels that contribute to excitatory neurotransmission in the central nervous system (CNS). Most NMDA receptors comprise two glycine-binding GluN1 and two glutamate-binding GluN2 subunits (GluN2A–D). We describe highly potent (S)-5-[(R)-2-amino-2-carboxyethyl]-4,5-dihydro-1H-pyrazole-3-carboxylic acid (ACEPC) competitive GluN2 antagonists, of which ST3 has a binding affinity of 52 nM at GluN1/2A and 782 nM at GluN1/2B receptors. This 15-fold preference of ST3 for GluN1/2A over GluN1/2B is improved compared with NVP-AAM077, a widely used GluN2A-selective antagonist, which we show has 11-fold preference for GluN1/2A over GluN1/2B. Crystal structures of the GluN1/2A agonist binding domain (ABD) heterodimer with bound ACEPC antagonists reveal a binding mode in which the ligands occupy a cavity that extends toward the subunit interface between GluN1 and GluN2A ABDs. Mutational analyses show that the GluN2A preference of ST3 is primarily mediated by four nonconserved residues that are not directly contacting the ligand, but positioned within 12 Å of the glutamate binding site. Two of these residues influence the cavity occupied by ST3 in a manner that results in favorable binding to GluN2A, but occludes binding to GluN2B. Thus, we reveal opportunities for the design of subunit-selective competitive NMDA receptor antagonists by identifying a cavity for ligand binding in which variations exist between GluN2A and GluN2B subunits. This structural insight suggests that subunit selectivity of glutamate-site antagonists can be mediated by mechanisms in addition to direct contributions of contact residues to binding affinity.

  12. Progress in the development of histamine H3 receptor antagonists/inverse agonists: a patent review (2013-2017).

    Science.gov (United States)

    Łażewska, Dorota; Kieć-Kononowicz, Katarzyna

    2018-03-01

    Since years, ligands blocking histamine H 3 receptor (H 3 R) activity (antagonists/inverse agonists) are interesting targets in the search for new cures for CNS disorders. Intensive works done by academic and pharmaceutical company researchers have led to many potent and selective H 3 R antagonists/inverse agonists. Some of them have reached to clinical trials. Areas covered: Patent applications from January 2013 to September 2017 and the most important topics connected with H 3 R field are analysed. Espacenet, Patentscope, Pubmed, GoogleScholar or Cochrane Library online databases were principially used to collect all the materials. Expert opinion: The research interest in histamine H 3 R field is still high although the number of patent applications has decreased during the past 4 years (around 20 publications). Complexity of histamine H 3 R biology e.g. many isoforms, constitutive activity, heteromerization with other receptors (dopamine D 2 , D 1 , adenosine A 2A ) and pharmacology make not easy realization and evaluation of therapeutic potential of anti-H 3 R ligands. First results from clinical trials have verified potential utility of histamine H 3 R antagonist/inverse agonists in some diseases. However, more studies are necessary for better understanding of an involvement of the histaminergic system in CNS-related disorders and helping more ligands approach to clinical trials and the market. Lists of abbreviations: hAChEI - human acetylcholinesterase inhibitor; hBuChEI - human butyrylcholinesterase inhibitor; hMAO - human monoamine oxidase; MAO - monoamine oxidase.

  13. Radiodinated L-703,606: a potent selective antagonist to the human NK[sub 1] receptor

    Energy Technology Data Exchange (ETDEWEB)

    Francis, B E; Burns, H D [Merck Research Labs., West Point, PA (United States). Dept. of Radiopharmacology; Swain, C; Sabin, V [Merck Sharp and Dohme Research Labs., Harlow (United Kingdom). The Neuroscience Centre

    1994-01-01

    A new, radioiodinated, NK[sub 1] selective radiotracer ([[sup 125]I]L-703,606) was prepared. L-703,606 is an iodinated analog of the NK[sub 1] antagonist CP-96,345 in which the methoxy group has been replaced by an iodine substituent. [[sup 125]I]L-703,606 was made from the corresponding trimethylsilyl compound by treatment with no carrier added Na[sub 125]I and an Iodobead in TFA. The tracer was prepared at a specific activity of approx. 1100 Ci/mmol and preliminary binding studies demonstrated that [[sup 125]I]L=703,606 binds selectively to NK[sub 1] receptors. These results suggest that this radioligand will be useful for the biochemical and pharmacological characterization of the human NK[sub 1] receptor and, if labeled with I-123, may be useful for non-invasive NK[sub 1] receptor imaging via SPECT. (author).

  14. Functional ET(A)-ET(B) Receptor Cross-talk in Basilar Artery In Situ From ET(B) Receptor Deficient Rats.

    Science.gov (United States)

    Yoon, SeongHun; Gariepy, Cheryl E; Yanagisawa, Masashi; Zuccarello, Mario; Rapoport, Robert M

    2016-03-01

    The role of endothelin (ET)(A)-ET(B) receptor cross-talk in limiting the ET(A) receptor antagonist inhibition of ET-1 constriction is revealed by the partial or complete dependency of the ET(A) receptor antagonist inhibition on functional removal of the ET(B) receptor. Although functional removal of the ET(B) receptor is generally accomplished with ET(B) receptor antagonist, a novel approach using rats containing a naturally occurring deletion mutation in the ET(B) receptor [rescued "spotting lethal" (sl) rats; ET(B)(sl/sl)] demonstrated increased ET(A) receptor antagonist inhibition of ET-1 constriction in vena cava. We investigated whether this deletion mutation was also sufficient to remove the ET(B) receptor dependency of the ET(A) receptor antagonist inhibition of ET-1 constriction in the basilar artery. Consistent with previous reports, ET-1 plasma levels were elevated in ET(B)(sl/sl) as compared with ET(B)(+/+) rats. ET(B) receptor antagonist failed to relax the ET-1 constricted basilar artery from ET(B)(+/+) and ET(B)(sl/sl) rats. Relaxation to combined ET(A) and ET(B) receptor antagonist was greater than relaxation to ET(A) receptor antagonist in the basilar artery from ET(B)(+/+) and, unexpectedly, ET(B)(sl/sl) rats. These findings confirm the presence of ET(A)-ET(B) receptor cross-talk in the basilar artery. We speculate that mutant ET(B) receptor expression produced by alternative splicing may be sufficient to allow cross-talk.

  15. Novel lipidized analogs of prolactin-releasing peptide have prolonged half-lives and exert anti-obesity effects after peripheral administration

    Czech Academy of Sciences Publication Activity Database

    Maletínská, Lenka; Nagelová, Veronika; Tichá, Anežka; Zemenová, Jana; Pirník, Zdenko; Holubová, Martina; Špolcová, Andrea; Mikulášková, Barbora; Blechová, Miroslava; Sýkora, D.; Lacinová, Z.; Haluzík, M.; Železná, Blanka; Kuneš, Jaroslav

    2015-01-01

    Roč. 39, č. 6 (2015), s. 986-993 ISSN 0307-0565 R&D Projects: GA ČR GAP303/10/1368; GA ČR GAP303/12/0576; GA TA ČR(CZ) TE01020028 Institutional support: RVO:61388963 Keywords : food intake * prolactin-releasing peptide * GPR10 receptor Subject RIV: CE - Biochemistry Impact factor: 5.337, year: 2015

  16. Potential Activity of Fevicordin-A from Phaleria macrocarpa (Scheff Boerl. Seeds as Estrogen Receptor Antagonist Based on Cytotoxicity and Molecular Modelling Studies

    Directory of Open Access Journals (Sweden)

    Muchtaridi Muchtaridi

    2014-04-01

    Full Text Available Fevicordin-A (FevA isolated from Phaleria macrocarpa (Scheff Boerl. seeds was evaluated for its potential anticancer activity by in vitro and in silico approaches. Cytotoxicity studies indicated that FevA was selective against cell lines of human breast adenocarcinoma (MCF-7 with an IC50 value of 6.4 µM. At 11.2 µM, FevA resulted in 76.8% cell death of T-47D human breast cancer cell lines. Critical pharmacophore features amongst human Estrogen Receptor-α (hERα antagonists were conserved in FevA with regard to a hypothesis that they could make notable contributions to its pharmacological activity. The binding stability as well as the dynamic behavior of FevA towards the hERα receptor in agonist and antagonist binding sites were probed using molecular dynamics (MD simulation approach. Analysis of MD simulation suggested that the tail of FevA was accountable for the repulsion of the C-terminal of Helix-11 (H11 in both agonist and antagonist receptor forms. The flexibility of loop-534 indicated the ability to disrupt the hydrogen bond zipper network between H3 and H11 in hERα. In addition, MM/GBSA calculation from the molecular dynamic simulations also revealed a stronger binding affinity of FevA in antagonistic action as compared to that of agonistic action. Collectively, both the experimental and computational results indicated that FevA has potential as a candidate for an anticancer agent, which is worth promoting for further preclinical evaluation.

  17. Identification of an endogenous alpha-adrenergic receptor antagonist: studies on its possible role in endocrine and cardiovascular function

    International Nuclear Information System (INIS)

    Dunbar, J.C.; Wider, M.; House, F.; Campbell, R.

    1986-01-01

    The concept of α and β adrenergic receptors that are regulated by epinephrine or norepinephrine (NE) is well established. The reported receptor antagonists have been synthetic. A peptide extracted from the duodenal mucosa with α-2 antagonist properties has been identified. It specifically inhibits 3 H-yohimbine binding (α-2) but not 3 H dihydroalprenolol (β) binding in whole brain membranes. Partially purified preparations of the alpha receptor binding inhibitor (ABI) were tested for endocrine pancreatic and cardiovascular effects. When isolated islets were incubated in the presence of ABI with and without NE, ABI along did not alter insulin secretion but completely reversed the NE suppression of glucose stimulated insulin release. Glucagon secretion by these same islets was enhanced by ABI and augmented the stimulatory effect of NE. Intravenous (I.V.) infusion of ABI increased serum insulin in the presence of NE and decreased the serum glucose response to a glucose load. Infusion of ABI into the 4th ventricle, or I.V. resulted in a decrease (50-60%) in systolic and diastolic blood pressure as well as a decrease (10-20%) in heart rate. From these studies the authors conclude that a duodenal peptide with the capacity to inhibit α-2 agonist binding may play a role in endocrine and cardiovascular functions

  18. 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...

  19. Ranakinestatin-PPF from the skin secretion of the Fukien gold-striped pond frog, Pelophylax plancyi fukienensis: a prototype of a novel class of bradykinin B2 receptor antagonist peptide from ranid frogs.

    Science.gov (United States)

    Ma, Jie; Luo, Yu; Ge, Lilin; Wang, Lei; Zhou, Mei; Zhang, Yingqi; Duan, Jinao; Chen, Tianbao; Shaw, Chris

    2014-01-01

    The defensive skin secretions of many amphibians are a rich source of bradykinins and bradykinin-related peptides (BRPs). Members of this peptide group are also common components of reptile and arthropod venoms due to their multiple biological functions that include induction of pain, effects on many smooth muscle types, and lowering systemic blood pressure. While most BRPs are bradykinin receptor agonists, some have curiously been found to be exquisite antagonists, such as the maximakinin gene-related peptide, kinestatin-a specific bradykinin B2-receptor antagonist from the skin of the giant fire-bellied toad, Bombina maxima. Here, we describe the identification, structural and functional characterization of a heptadecapeptide (DYTIRTRLHQGLSRKIV), named ranakinestatin-PPF, from the skin of the Chinese ranid frog, Pelophylax plancyi fukienensis, representing a prototype of a novel class of bradykinin B2-receptor specific antagonist. Using a preconstricted preparation of rat tail arterial smooth muscle, a single dose of 10(-6)M of the peptide effectively inhibited the dose-dependent relaxation effect of bradykinin between 10(-11)M and 10(-5)M and subsequently, this effect was pharmacologically-characterized using specific bradykinin B1- (desArg-HOE140) and B2-receptor (HOE140) antagonists; the data from which demonstrated that the antagonism of the novel peptide was mediated through B2-receptors. Ranakinestatin-PPF-thus represents a prototype of an amphibian skin peptide family that functions as a bradykinin B2-receptor antagonist herein demonstrated using mammalian vascular smooth muscle.

  20. 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.

  1. Dopamine D2/3- and μ-opioid receptor antagonists reduce cue-induced responding and reward impulsivity in humans.

    Science.gov (United States)

    Weber, S C; Beck-Schimmer, B; Kajdi, M-E; Müller, D; Tobler, P N; Quednow, B B

    2016-07-05

    Increased responding to drug-associated stimuli (cue reactivity) and an inability to tolerate delayed gratification (reward impulsivity) have been implicated in the development and maintenance of drug addiction. Whereas data from animal studies suggest that both the dopamine and opioid system are involved in these two reward-related processes, their role in humans is less clear. Moreover, dopaminergic and opioidergic drugs have not been directly compared with regard to these functions, even though a deeper understanding of the underlying mechanisms might inform the development of specific treatments for elevated cue reactivity and reward impulsivity. In a randomized, double-blind, between-subject design we administered the selective dopamine D2/D3 receptor antagonist amisulpride (400 mg, n=41), the unspecific opioid receptor antagonist naltrexone (50 mg, n=40) or placebo (n=40) to healthy humans and measured cue-induced responding with a Pavlovian-instrumental transfer task and reward impulsivity with a delay discounting task. Mood was assessed using a visual analogue scale. Compared with placebo, amisulpride significantly suppressed cue-induced responding and reward impulsivity. The effects of naltrexone were similar, although less pronounced. Both amisulpride and naltrexone decreased average mood ratings compared with placebo. Our results demonstrate that a selective blockade of dopamine D2/D3 receptors reduces cue-induced responding and reward impulsivity in healthy humans. Antagonizing μ-opioid receptors has similar effects for cue-induced responding and to a lesser extent for reward impulsivity.

  2. Minocycline exacerbates apoptotic neurodegeneration induced by the NMDA receptor antagonist MK-801 in the early postnatal mouse brain.

    Science.gov (United States)

    Inta, Ioana; Vogt, Miriam A; Vogel, Anne S; Bettendorf, Markus; Gass, Peter; Inta, Dragos

    2016-10-01

    NMDA receptor (NMDAR) antagonists induce in perinatal rodent cortical apoptosis and protracted schizophrenia-like alterations ameliorated by antipsychotic treatment. The broad-spectrum antibiotic minocycline elicits antipsychotic and neuroprotective effects. Here we tested, if minocycline protects also against apoptosis triggered by the NMDAR antagonist MK-801 at postnatal day 7. Surprisingly, minocycline induced widespread cortical apoptosis and exacerbated MK-801-triggered cell death. In some areas such as the subiculum, the pro-apoptotic effect of minocycline was even more pronounced than that elicited by MK-801. These data reveal among antipsychotics unique pro-apoptotic properties of minocycline, raising concerns regarding consequences for brain development and the use in children.

  3. Effects of the 5-HT7 receptor antagonists SB-269970 and DR 4004 in autoshaping Pavlovian/instrumental learning task.

    Science.gov (United States)

    Meneses, Alfredo

    2004-12-06

    There is an important debate regarding the functional role of the 5-HT(1A) and 5-HT(7) receptor in memory systems. Hence, the objective of this paper is to investigate the function of serotonin (5-hydroxytryptamine, 5-HT) in memory consolidation, utilising an autoshaping Pavlovian/instrumental learning test. Specific antagonists at 5-HT(1A) (WAY 100635) and 5-HT(7) (SB-269970 or DR 4004) receptors administered i.p. or s.c.) after training, significantly decreased the improvement of performance produced by the 5-HT(1A/7) agonist 8-OH-DPAT to levels lower than controls'. These same antagonists attenuated the decreased level of performance produced by mCPP, although they decrease the performance levels after p-chloroamphetamine (PCA) lesion of the 5-HT system, which has no effect on its own on the conditioned response. Moreover, SB-269970 or DR 4004 reversed amnesia induced by scopolamine and dizocilpine. These data confirm a role for 5-HT(1A) and 5-HT(7) receptors in memory formation and support the hypothesis that serotonergic, cholinergic, and glutamatergic systems interact in cognitively impaired animals. These findings support a potential role for both 5-HT(1A) and 5-HT(7) receptors in the pathophysiology and/or treatment of schizophrenia, cognitive deficits and the mechanism of action of atypical antipsychotic drugs.

  4. 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

  5. Positive Modulatory Interactions of NMDA Receptor GluN1/2B Ligand Binding Domains Attenuate Antagonists Activity

    Directory of Open Access Journals (Sweden)

    Douglas Bledsoe

    2017-05-01

    Full Text Available N-methyl D-aspartate receptors (NMDAR play crucial role in normal brain function and pathogenesis of neurodegenerative and psychiatric disorders. Functional tetra-heteromeric NMDAR contains two obligatory GluN1 subunits and two identical or different non-GluN1 subunits that include six different gene products; four GluN2 (A–D and two GluN3 (A–B subunits. The heterogeneity of subunit combination facilities the distinct function of NMDARs. All GluN subunits contain an extracellular N-terminal Domain (NTD and ligand binding domain (LBD, transmembrane domain (TMD and an intracellular C-terminal domain (CTD. Interaction between the GluN1 and co-assembling GluN2/3 subunits through the LBD has been proven crucial for defining receptor deactivation mechanisms that are unique for each combination of NMDAR. Modulating the LBD interactions has great therapeutic potential. In the present work, by amino acid point mutations and electrophysiology techniques, we have studied the role of LBD interactions in determining the effect of well-characterized pharmacological agents including agonists, competitive antagonists, and allosteric modulators. The results reveal that agonists (glycine and glutamate potency was altered based on mutant amino acid sidechain chemistry and/or mutation site. Most antagonists inhibited mutant receptors with higher potency; interestingly, clinically used NMDAR channel blocker memantine was about three-fold more potent on mutated receptors (N521A, N521D, and K531A than wild type receptors. These results provide novel insights on the clinical pharmacology of memantine, which is used for the treatment of mild to moderate Alzheimer's disease. In addition, these findings demonstrate the central role of LBD interactions that can be exploited to develop novel NMDAR based therapeutics.

  6. Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids

    DEFF Research Database (Denmark)

    Kromann, Hasse; Sløk, Frank A; Stensbøl, Tine B

    2002-01-01

    Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are bot...... antagonists at group I mGluRs. Here we report the synthesis and molecular pharmacology of HIBO analogues 9b-h containing different 4-aryl substituents. All of these compounds possess antagonist activity at group I mGluRs but are inactive at group II and III mGluRs....

  7. A systematic review and meta-analysis of the impact of mineralocorticoid receptor antagonists on glucose homeostasis

    OpenAIRE

    Korol, Sandra; Mottet, Fannie; Perreault, Sylvie; Baker, William L.; White, Michel; de Denus, Simon

    2017-01-01

    Abstract Background: Spironolactone, a nonselective mineralocorticoid receptor antagonist (MRA), may have a deleterious effect on glycemia. The objective of this review was to assess current knowledge on MRAs’ influence (spironolactone, eplerenone, and canrenone) on glucose homeostasis and the risk of diabetes. Method: A systematic review was conducted using the Medline database on articles published from 1946 to January 2017 that studied the effects of MRAs on any glucose-related endpoints, ...

  8. Opioid analgesics as noncompetitive N-methyl-D-aspartate (NMDA) antagonists

    DEFF Research Database (Denmark)

    Ebert, B; Thorkildsen, C; Andersen, S

    1998-01-01

    Much evidence points to the involvement of N-methyl-D-aspartate (NMDA) receptors in the development and maintainance of neuropathic pain. In neuropathic pain, there is generally involved a presumed opioid-insensitive component, which apparently can be blocked by NMDA receptor antagonists. However...... for the NMDA receptor antagonism of these compounds and its relevance for clinical pain treatment; an overview of structure-activity relationships for the relevant opioids as noncompetitive NMDA receptor antagonists also is given. It is concluded that although the finding that some opioids are weak...

  9. The effects of intraperitoneal and intracerebroventricular administration of the GABAB receptor antagonist CGP 35348 on food intake in rats.

    Science.gov (United States)

    Patel, Sunit M; Ebenezer, Ivor S

    2004-10-25

    In order to test the hypothesis that endogenous gamma-aminobutyric acid (GABA), acting at central GABAB receptors, plays a physiological role in the control of feeding behaviour, it was reasoned that blocking these receptors with a centrally active GABAB receptor antagonist should reduce food intake in hungry rats. In the present study, experiments were carried out to test this possibility using the GABAB receptor antagonist 3-aminopropyl-diethoxy-methyl-phosphinic acid (CGP 35348), which is water-soluble and can penetrate the blood-brain barrier from the systemic circulation. CGP 35348 (50 and 100 mg/kg, i.p.) had no effect on food intake in 22-h fasted rats, but a higher dose (i.e. 500 mg/kg., i.p.) significantly reduced cumulative food consumption. These findings are consistent with previous observations that high systemic doses of CGP 35348 are needed to block central GABAB receptors. However, to eliminate the possibility that the 500 mg/kg dose of CGP 35348 decreased food intake by a peripheral, rather than a central mode of action, further experiments were undertaken where the drug was given directly into the brain by the intracerebroventricular (i.c.v.) route. I.c.v. administration of CGP 35348 (5 and 10 microg) significantly decreased cumulative food intake food intake in rats that had been fasted for 22 h. By contrast, i.c.v. administration of CGP 35348 (10 microg) had no effect on water intake in 16-h water-deprived rats. The results indicate that CGP 35348 reduces food consumption in hungry rats by blocking central GABAB receptors in a behaviourally specific manner. These findings suggest that endogenous GABA acting at central GABAB receptors plays a physiological role in the regulation of feeding behaviour.

  10. Ontogenic studies of the neural control of adenohypophyseal hormones in the rat. II. Prolactin.

    Science.gov (United States)

    Becú-Villalobos, D; Lacau-Mengido, I M; Díaz-Torga, G S; Libertun, C

    1992-02-01

    1. Serum prolactin levels are low during the first 20 days of life and gradually increase toward puberty, in both male and female rats. 2. There is an age-related increase in the cell population engaged in prolactin secretion, as well as an increase in the synthesis of prolactin and of the amount of prolactin secreted from individual lactotropes. 3. The gradual increase in prolactin levels in the third week of life is not related to a decrease in dopaminergic inhibition but to an increase in the efficiency of prolactin releasing factors such as estrogen, serotonin, opiates, and posterior pituitary extracts. 4. Prolactin release induced by physiological factors, such as stress, cervical stimulation, or the expression of spontaneous diurnal and nocturnal surges, requires maturational events within the hypothalamic-pituitary axis which are evident at the end of the third week of life. 5. In the female rat the steadily increasing levels of prolactin are involved in the timing of puberty eclosion acting at the ovary and at the brain. 6. In the prepubertal male rat increasing titers of prolactin may be involved in testicular and accessory organ development and may facilitate the actions of luteinizing hormone, follicle stimulating hormone, and testosterone on male sexual organs.

  11. 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.

  12. Correlation between FSH, LH and prolactin serum levels. [Radioimmunoassay of hormones

    Energy Technology Data Exchange (ETDEWEB)

    Krause, W [Giessen Univ. (Germany, F.R.)

    1978-01-01

    In 188 males FSH, LH, and prolactin serum levels determined by radioimmunoassay from a single blood sample were found to be closely correlated. No correlation appeared to testosterone levels. The same correlation is observed, if serum levels of FSH, LH, and prolactin are measured after stimulation with LH-RH and TRH. In order to explain the close correlation, in five young men hormone levels were measured at 2-min-intervals over a period of 2 hours. Peaks of prolactin often correspond to those of FSH and LH, and a statistical correlation was found in two cases between FSH and prolactin. Results suggest a common releasing mechanism, which is superposed to the main mediating mechanism.

  13. Relationship between structure, conformational flexibility, and biological activity of agonists and antagonists at the N-methyl-D-aspartic acid subtype of excitatory amino acid receptors

    DEFF Research Database (Denmark)

    Madsen, U; Brehm, L; Schaumburg, Kjeld

    1990-01-01

    The relationship between conformational flexibility and agonist or antagonist actions at the N-Methyl-D-aspartic acid (NMDA) subtype of central L-glutamic acid (GLU) receptors of a series of racemic piperidinedicarboxylic acids (PDAs) was studied. The conformational analyses were based on 1H NMR...... receptors. Each of the three cyclic acidic amino acids showing NMDA agonist activities was found to exist as an equilibrium mixture of two conformers in aqueous solution. In contrast, the NMDA antagonists cis-2,3-PDA and cis-2,4-PDA as well as the inactive compounds trans-2,5-PDA and cis-2,6-PDA were shown...

  14. Effect of leukotriene receptor antagonists on vascular permeability during endotoxic shock

    International Nuclear Information System (INIS)

    Cook, J.A.; Li, E.J.; Spicer, K.M.; Wise, W.C.; Halushka, P.V.

    1990-01-01

    Evidence has accumulated that sulfidopeptide leukotrienes are significant pathogenic mediators of certain hematologic and hemodynamic sequelae of endotoxic shock. In the present study, the effects of a selective LTD4/E4 receptor antagonist, LY171883 (LY), or a selective LTD4 receptor antagonist, SKF-104353 (SKF), were assessed on splanchnic and pulmonary localization of 99mTechnetium-labeled human serum albumin (99mTc-HSA) in acute endotoxic shock in the rat. Dynamic gamma camera imaging of heart (H), midabdominal (GI), and lung regions of interest generated time activity curves for baseline and at 5-35 min after Salmonella enteritidis endotoxin (10 mg/kg, i.v.). Slopes of GI/H and lung/H activity (permeability index, GI/H or lung/H X 10(-3)/min) provided indices of intestinal and lung localization. Rats received LY (30 mg/kg, i.v.), LY vehicle (LY Veh), SKF (10 mg/kg), or SKF vehicle (SK Veh) 10 min prior to endotoxin or endotoxin vehicle. In rats receiving the LY Veh and endotoxin (n = 8) or SKF Veh and endotoxin (n = 12), the splanchnic permeability indices to 99mTc-HSA were increased 11.2-fold and 5.1-fold, respectively (P less than 0.05) compared to vehicle control groups not given endotoxin (n = 5). Pulmonary permeability index for 99mTc-HSA was increased (P less than 0.05) to a lesser extent (3.2-fold) by endotoxin compared to vehicle controls. Pretreatment with SKF reduced the mesenteric permeability index to control levels (P less than 0.05) during the 5-35 min time interval post-endotoxin. LY reduced the mesenteric permeability index by 70%. Pulmonary relative permeability to 99mTc-HSA was not affected by LY pretreatment. Both splanchnic and lung relative permeability to the isotope was transient; at 135-225 min post-endotoxin, splanchnic localization of 99mTc-HSA (n = 4) was not significantly different from vehicle controls in these vascular beds

  15. Dynamical Binding Modes Determine Agonistic and Antagonistic Ligand Effects in the Prostate-Specific G-Protein Coupled Receptor (PSGR).

    Science.gov (United States)

    Wolf, Steffen; Jovancevic, Nikolina; Gelis, Lian; Pietsch, Sebastian; Hatt, Hanns; Gerwert, Klaus

    2017-11-22

    We analysed the ligand-based activation mechanism of the prostate-specific G-protein coupled receptor (PSGR), which is an olfactory receptor that mediates cellular growth in prostate cancer cells. Furthermore, it is an olfactory receptor with a known chemically near identic antagonist/agonist pair, α- and β-ionone. Using a combined theoretical and experimental approach, we propose that this receptor is activated by a ligand-induced rearrangement of a protein-internal hydrogen bond network. Surprisingly, this rearrangement is not induced by interaction of the ligand with the network, but by dynamic van der Waals contacts of the ligand with the involved amino acid side chains, altering their conformations and intraprotein connectivity. Ligand recognition in this GPCR is therefore highly stereo selective, but seemingly lacks any ligand recognition via polar contacts. A putative olfactory receptor-based drug design scheme will have to take this unique mode of protein/ligand action into account.

  16. Methylmercury inhibits prolactin release in a cell line of pituitary origin

    Directory of Open Access Journals (Sweden)

    L.A.L. Maués

    2015-08-01

    Full Text Available Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6. Exposure to methylmercury (0-100 μM was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.

  17. Chronic psychosocial stress in tree shrews : effect of the substance P (NK1 receptor) antagonist L-760735 and clomipramine on endocrine and behavioral parameters

    NARCIS (Netherlands)

    van der Hart, MGC; de Biurrun, G; Czeh, B; Rupniak, NMJ; den Boer, JA; Fuchs, E

    Rationale: Substance P and its preferred receptor, the neurokinin 1 receptor (NK1R), have been proposed as possible targets for new antidepressant therapies, although results of a recently completed phase III trial failed to demonstrate that the NK1R antagonist MK-869 is more effective than placebo

  18. Enhanced prolactin levels in opium smokers.

    Science.gov (United States)

    Moshtaghi-Kashanian, Ghollam-Reza; Esmaeeli, Farzaneh; Dabiri, Shahriar

    2005-12-01

    In Iran, opium is smoked for pleasure or as a medication by some people. It is a complex mixture of 40 different alkaloids, including morphine and codeine along with many impurities. Although it is well established that opioids or tobacco affect many physiological functions in humans, to our knowledge there has been no specific study looking at these effects in opium smokers. To assess that, we investigated the circulating levels of prolactin, TSH, LH, FSH and testosterone in male opium smokers who also smoke cigarettes (n=23, aged 28.4+/- 4.1 years), and comparing this with the corresponding values for nicotine abusers (n=12, 15-25 cigarettes/day) or a healthy control group (n=20) of the same age. Our results showed that 86.96% of the opium-dependent and 41.67 % of the nicotine-dependent group displayed high prolactin values (popium and the plasma prolactin level of opium dependents (p=0.748, popium smokers and 50% of the cigarette smokers (popium smokers was also lower than that of the other two groups (popium and cigarette smoking may synergistically influence pituitary hormone production through the effects on neuropeptides produced either locally or systemic.

  19. Prolactin and Dehydroepiandrosterone Levels in Women with Systemic Lupus Erythematosus: The Role of the Extrapituitary Prolactin Promoter Polymorphism at −1149G/T

    Directory of Open Access Journals (Sweden)

    Edward L. Treadwell

    2015-01-01

    Full Text Available Systemic lupus erythematosus (SLE has shown an association with high levels of prolactin, low levels of dehydroepiandrosterone (DHEA, and induction of inflammatory cytokines in the serum of patients with the disease. This preliminary study examined the relevance of a −1149G/T functional single-nucleotide polymorphism (SNP (rs1341239 in the promoter of the extrapituitary prolactin gene in a cohort of African American and European American women with lupus. Examination of this SNP revealed that the −1149TT genotype was correlated with higher levels of prolactin in serum and prolactin gene expression (p=0.0001 in peripheral blood mononuclear cells (PBMCs. Lower levels of DHEA in serum were demonstrated in lupus patients (p=0.001; those with the −1149TT genotype had the lowest levels of DHEA. Furthermore, a small subset of women who were on DHEA therapy and had a TT genotype showed a significant decrease in prolactin gene expression and lower disease activity scores (SLEDAI. Lupus patients, particularly African Americans, had significantly higher levels of IL-6 (p=0.0001 and TNF-α (p=0.042. This study suggests that the −1149TT genotype may be a risk factor for lupus and may predict who could possibly benefit from DHEA therapy; therefore, these results should be validated in a larger cohort with all ethnic groups.

  20. Ranakinestatin-PPF from the Skin Secretion of the Fukien Gold-Striped Pond Frog, Pelophylax plancyi fukienensis: A Prototype of a Novel Class of Bradykinin B2 Receptor Antagonist Peptide from Ranid Frogs

    Directory of Open Access Journals (Sweden)

    Jie Ma

    2014-01-01

    Full Text Available The defensive skin secretions of many amphibians are a rich source of bradykinins and bradykinin-related peptides (BRPs. Members of this peptide group are also common components of reptile and arthropod venoms due to their multiple biological functions that include induction of pain, effects on many smooth muscle types, and lowering systemic blood pressure. While most BRPs are bradykinin receptor agonists, some have curiously been found to be exquisite antagonists, such as the maximakinin gene-related peptide, kinestatin—a specific bradykinin B2-receptor antagonist from the skin of the giant fire-bellied toad, Bombina maxima. Here, we describe the identification, structural and functional characterization of a heptadecapeptide (DYTIRTRLHQGLSRKIV, named ranakinestatin-PPF, from the skin of the Chinese ranid frog, Pelophylax plancyi fukienensis, representing a prototype of a novel class of bradykinin B2-receptor specific antagonist. Using a preconstricted preparation of rat tail arterial smooth muscle, a single dose of 10−6 M of the peptide effectively inhibited the dose-dependent relaxation effect of bradykinin between 10−11 M and 10−5 M and subsequently, this effect was pharmacologically-characterized using specific bradykinin B1- (desArg-HOE140 and B2-receptor (HOE140 antagonists; the data from which demonstrated that the antagonism of the novel peptide was mediated through B2-receptors. Ranakinestatin—PPF—thus represents a prototype of an amphibian skin peptide family that functions as a bradykinin B2-receptor antagonist herein demonstrated using mammalian vascular smooth muscle.

  1. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

    Science.gov (United States)

    Michinaga, Shotaro; Nagase, Marina; Matsuyama, Emi; Yamanaka, Daisuke; Seno, Naoki; Fuka, Mayu; Yamamoto, Yui; Koyama, Yutaka

    2014-01-01

    Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs) are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice). Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV) administration of BQ788 (ETB antagonist), IRL-2500 (ETB antagonist), or FR139317 (ETA antagonist) prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  2. Prolactin and cortisol levels in women with endometriosis

    Directory of Open Access Journals (Sweden)

    A.P. Lima

    2006-08-01

    Full Text Available Endometriosis is a progressive estrogen-dependent disease affecting women during their reproductive years. The objective of the present study was to investigate whether endometriosis is associated with stress parameters. We determined cortisol and prolactin levels in serum, peritoneal and follicular fluid from infertile women with endometriosis and fertile women without the disease. The extent of the disease was staged according to the revised American Fertility Society classification (1997. Serum and peritoneal fluid were collected from 49 women aged 19 to 39 years undergoing laparoscopy. Eighteen women had stage I-II endometriosis and 10 had stage III-IV. Controls were 21 women undergoing laparoscopy for tubal sterilization. Follicular fluid was obtained from 39 women aged 25-39 years undergoing in vitro fertilization (21 infertile women with endometriosis and 18 infertile women without endometriosis. Serum prolactin levels were significantly higher in infertile women with stage III-IV endometriosis (28.9 ± 2.1 ng/mL than in healthy controls (13.2 ± 2.1 ng/mL. Serum cortisol levels were significantly higher in infertile women with stage III-IV endometriosis (20.1 ± 1.3 ng/mL than in controls (10.5 ± 1.4 ng/mL. Cortisol and prolactin levels in follicular fluid and peritoneal fluid did not differ significantly between groups. The high levels of cortisol and prolactin in the serum from women with endometriosis might contribute to the subfertility frequently associated with the disease. Moreover, since higher levels of cortisol and prolactin are often associated with stress, it is probable that stress might contribute to the development of endometriosis and its progression to advanced stages of the disease.

  3. Discovery of (1R,2S)-2-{[(2,4-Dimethylpyrimidin-5-yl)oxy]methyl}-2-(3-fluorophenyl)-N-(5-fluoropyridin-2-yl)cyclopropanecarboxamide (E2006): A Potent and Efficacious Oral Orexin Receptor Antagonist.

    Science.gov (United States)

    Yoshida, Yu; Naoe, Yoshimitsu; Terauchi, Taro; Ozaki, Fumihiro; Doko, Takashi; Takemura, Ayumi; Tanaka, Toshiaki; Sorimachi, Keiichi; Beuckmann, Carsten T; Suzuki, Michiyuki; Ueno, Takashi; Ozaki, Shunsuke; Yonaga, Masahiro

    2015-06-11

    The orexin/hypocretin receptors are a family of G protein-coupled receptors and consist of orexin-1 (OX1) and orexin-2 (OX2) receptor subtypes. Orexin receptors are expressed throughout the central nervous system and are involved in the regulation of the sleep/wake cycle. Because modulation of these receptors constitutes a promising target for novel treatments of disorders associated with the control of sleep and wakefulness, such as insomnia, the development of orexin receptor antagonists has emerged as an important focus in drug discovery research. Here, we report the design, synthesis, characterization, and structure-activity relationships (SARs) of novel orexin receptor antagonists. Various modifications made to the core structure of a previously developed compound (-)-5, the lead molecule, resulted in compounds with improved chemical and pharmacological profiles. The investigation afforded a potential therapeutic agent, (1R,2S)-2-{[(2,4-dimethylpyrimidin-5-yl)oxy]methyl}-2-(3-fluorophenyl)-N-(5-fluoropyridin-2-yl)cyclopropanecarboxamide (E2006), an orally active, potent orexin antagonist. The efficacy was demonstrated in mice in an in vivo study by using sleep parameter measurements.

  4. Characterization of JNJ-42847922, a Selective Orexin-2 Receptor Antagonist, as a Clinical Candidate for the Treatment of Insomnia.

    Science.gov (United States)

    Bonaventure, Pascal; Shelton, Jonathan; Yun, Sujin; Nepomuceno, Diane; Sutton, Steven; Aluisio, Leah; Fraser, Ian; Lord, Brian; Shoblock, James; Welty, Natalie; Chaplan, Sandra R; Aguilar, Zuleima; Halter, Robin; Ndifor, Anthony; Koudriakova, Tatiana; Rizzolio, Michele; Letavic, Michael; Carruthers, Nicholas I; Lovenberg, Timothy; Dugovic, Christine

    2015-09-01

    Dual orexin receptor antagonists have been shown to promote sleep in various species, including humans. Emerging research indicates that selective orexin-2 receptor (OX2R) antagonists may offer specificity and a more adequate sleep profile by preserving normal sleep architecture. Here, we characterized JNJ-42847922 ([5-(4,6-dimethyl-pyrimidin-2-yl)-hexahydro-pyrrolo[3,4-c]pyrrol-2-yl]-(2-fluoro-6-[1,2,3]triazol-2-yl-phenyl)-methanone), a high-affinity/potent OX2R antagonist. JNJ-42847922 had an approximate 2-log selectivity ratio versus the human orexin-1 receptor. Ex vivo receptor binding studies demonstrated that JNJ-42847922 quickly occupied OX2R binding sites in the rat brain after oral administration and rapidly cleared from the brain. In rats, single oral administration of JNJ-42847922 (3-30 mg/kg) during the light phase dose dependently reduced the latency to non-rapid eye movement (NREM) sleep and prolonged NREM sleep time in the first 2 hours, whereas REM sleep was minimally affected. The reduced sleep onset and increased sleep duration were maintained upon 7-day repeated dosing (30 mg/kg) with JNJ-42847922, then all sleep parameters returned to baseline levels following discontinuation. Although the compound promoted sleep in wild-type mice, it had no effect in OX2R knockout mice, consistent with a specific OX2R-mediated sleep response. JNJ-42847922 did not increase dopamine release in rat nucleus accumbens or produce place preference in mice after subchronic conditioning, indicating that the compound lacks intrinsic motivational properties in contrast to zolpidem. In a single ascending dose study conducted in healthy subjects, JNJ-42847922 increased somnolence and displayed a favorable pharmacokinetic and safety profile for a sedative/hypnotic, thus emerging as a promising candidate for further clinical development for the treatment of insomnia. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  5. 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...

  6. Brain prolactin is involved in stress-induced REM sleep rebound.

    Science.gov (United States)

    Machado, Ricardo Borges; Rocha, Murilo Ramos; Suchecki, Deborah

    2017-03-01

    REM sleep rebound is a common behavioural response to some stressors and represents an adaptive coping strategy. Animals submitted to multiple, intermittent, footshock stress (FS) sessions during 96h of REM sleep deprivation (REMSD) display increased REM sleep rebound (when compared to the only REMSD ones, without FS), which is correlated to high plasma prolactin levels. To investigate whether brain prolactin plays a role in stress-induced REM sleep rebound two experiments were carried out. In experiment 1, rats were either not sleep-deprived (NSD) or submitted to 96h of REMSD associated or not to FS and brains were evaluated for PRL immunoreactivity (PRL-ir) and determination of PRL concentrations in the lateral hypothalamus and dorsal raphe nucleus. In experiment 2, rats were implanted with cannulas in the dorsal raphe nucleus for prolactin infusion and were sleep-recorded. REMSD associated with FS increased PRL-ir and content in the lateral hypothalamus and all manipulations increased prolactin content in the dorsal raphe nucleus compared to the NSD group. Prolactin infusion in the dorsal raphe nucleus increased the time and length of REM sleep episodes 3h after the infusion until the end of the light phase of the day cycle. Based on these results we concluded that brain prolactin is a major mediator of stress-induced REMS. The effect of PRL infusion in the dorsal raphe nucleus is discussed in light of the existence of a bidirectional relationship between this hormone and serotonin as regulators of stress-induced REM sleep rebound. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. 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.

  8. Effect of Changes in Prolactin RIA Reactants on the Validity of the Results

    International Nuclear Information System (INIS)

    Ahmed, A.M.; Megahed, Y.M.; El Mosallamy, M.A.F.; El-Khoshnia, R.A.M.

    1998-01-01

    Human prolactin plays an essential role in the secretion of milk and has the ability to suppress gonadal function. This study is considered as atrial to discuss some technical problems which made by operator in the RIA technique to select an optimized reliable and valid parameters for the measurement of prolactin concentration in human sera. Prolactin concentration was measured in normal control group and chronic renal failure group using the optimized technique. Finally the present optimized technique is very suitable selected one for measurement of prolactin

  9. General, kappa, delta and mu opioid receptor antagonists mediate feeding elicited by the GABA-B agonist baclofen in the ventral tegmental area and nucleus accumbens shell in rats: reciprocal and regional interactions.

    Science.gov (United States)

    Miner, Patricia; Shimonova, Lyudmila; Khaimov, Arthur; Borukhova, Yaffa; Ilyayeva, Ester; Ranaldi, Robert; Bodnar, Richard J

    2012-03-14

    Food intake is significantly increased following administration of agonists of GABA and opioid receptors into the nucleus accumbens shell (NACs) and ventral tegmental area (VTA). GABA-A or GABA-B receptor antagonist pretreatment within the VTA or NACs differentially affects mu-opioid agonist-induced feeding elicited from the same site. Correspondingly, general or selective opioid receptor antagonist pretreatment within the VTA or NACs differentially affects GABA agonist-induced feeding elicited from the same site. Regional interactions have been evaluated in feeding studies by administering antagonists in one site prior to agonist administration in a second site. Thus, opioid antagonist-opioid agonist and GABA antagonist-GABA agonist feeding interactions have been identified between the VTA and NACs. However, pretreatment with GABA-A or GABA-B receptor antagonists in the VTA failed to affect mu opioid agonist-induced feeding elicited from the NACs, and correspondingly, these antagonists administered in the NACs failed to affect mu opioid-induced feeding elicited from the VTA. To evaluate whether regional and reciprocal VTA and NACs feeding interactions occur for opioid receptor modulation of GABA agonist-mediated feeding, the present study examined whether feeding elicited by the GABA-B agonist, baclofen microinjected into the NACs was dose-dependently blocked by pretreatment with general (naltrexone: NTX), mu (beta-funaltrexamine: BFNA), kappa (nor-binaltorphamine: NBNI) or delta (naltrindole: NTI) opioid antagonists in the VTA, and correspondingly, whether VTA baclofen-induced feeding was dose-dependently blocked by NACs pretreatment with NTX, BFNA, NBNI or NTI in rats. Bilateral pairs of cannulae aimed at the VTA and NACs were stereotaxically implanted in rats, and their food intakes were assessed following vehicle and baclofen (200 ng) in each site. Baclofen produced similar magnitudes of increased food intake following VTA and NACs treatment. Baclofen

  10. ACTH antagonists

    Directory of Open Access Journals (Sweden)

    Adrian John Clark

    2016-08-01

    Full Text Available ACTH acts via a highly selective receptor that is a member of the melanocortin receptor subfamily of type 1 G protein-coupled receptors. The ACTH receptor, also known as the melanocortin 2 receptor (MC2R is unusual in that it is absolutely dependent on a small accessory protein, melanocortin receptor accessory protein (MRAP for cell surface expression and function. ACTH is the only known naturally occurring agonist for this receptor. This lack of redundancy and high degree of ligand specificity suggests that antagonism of this receptor could provide a useful therapeutic aid and a potential investigational tool. Clinical situations in which this could be useful include (1 Cushing’s disease and ectopic ACTH syndrome – especially whilst preparing for definitive treatment of a causative tumour, or in refractory cases, or (2 congenital adrenal hyperplasia – as an adjunct to glucocorticoid replacement. A case for antagonism in other clinical situations in which there is ACTH excess can also be made. In this article we will explore the scientific and clinical case for an ACTH antagonist, and will review the evidence for existing and recently described peptides and modified peptides in this role.

  11. Biotransformation of the mineralocorticoid receptor antagonists spironolactone and canrenone by human CYP11B1 and CYP11B2: Characterization of the products and their influence on mineralocorticoid receptor transactivation.

    Science.gov (United States)

    Schiffer, Lina; Müller, Anne-Rose; Hobler, Anna; Brixius-Anderko, Simone; Zapp, Josef; Hannemann, Frank; Bernhardt, Rita

    2016-10-01

    Spironolactone and its major metabolite canrenone are potent mineralocorticoid receptor antagonists and are, therefore, applied as drugs for the treatment of primary aldosteronism and essential hypertension. We report that both compounds can be converted by the purified adrenocortical cytochromes P450 CYP11B1 and CYP11B2, while no conversion of the selective mineralocorticoid receptor antagonist eplerenone was observed. As their natural function, CYP11B1 and CYP11B2 carry out the final steps in the biosynthesis of gluco- and mineralocorticoids. Dissociation constants for the new exogenous substrates were determined by a spectroscopic binding assay and demonstrated to be comparable to those of the natural substrates, 11-deoxycortisol and 11-deoxycorticosterone. Metabolites were produced at preparative scale with a CYP11B2-dependent Escherichia coli whole-cell system and purified by HPLC. Using NMR spectroscopy, the metabolites of spironolactone were identified as 11β-OH-spironolactone, 18-OH-spironolactone and 19-OH-spironolactone. Canrenone was converted to 11β-OH-canrenone, 18-OH-canrenone as well as to the CYP11B2-specific product 11β,18-diOH-canrenone. Therefore, a contribution of CYP11B1 and CYP11B2 to the biotransformation of drugs should be taken into account and the metabolites should be tested for their potential toxic and pharmacological effects. A mineralocorticoid receptor transactivation assay in antagonist mode revealed 11β-OH-spironolactone as pharmaceutically active metabolite, whereas all other hydroxylation products negate the antagonist properties of spironolactone and canrenone. Thus, human CYP11B1 and CYP11B2 turned out to metabolize steroid-based drugs additionally to the liver-dependent biotransformation of drugs. Compared with the action of the parental drug, changed properties of the metabolites at the target site have been observed. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Development of a human vasopressin V1a-receptor antagonist from an evolutionary-related insect neuropeptide

    Science.gov (United States)

    di Giglio, Maria Giulia; Muttenthaler, Markus; Harpsøe, Kasper; Liutkeviciute, Zita; Keov, Peter; Eder, Thomas; Rattei, Thomas; Arrowsmith, Sarah; Wray, Susan; Marek, Ales; Elbert, Tomas; Alewood, Paul F.; Gloriam, David E.; Gruber, Christian W.

    2017-02-01

    Characterisation of G protein-coupled receptors (GPCR) relies on the availability of a toolbox of ligands that selectively modulate different functional states of the receptors. To uncover such molecules, we explored a unique strategy for ligand discovery that takes advantage of the evolutionary conservation of the 600-million-year-old oxytocin/vasopressin signalling system. We isolated the insect oxytocin/vasopressin orthologue inotocin from the black garden ant (Lasius niger), identified and cloned its cognate receptor and determined its pharmacological properties on the insect and human oxytocin/vasopressin receptors. Subsequently, we identified a functional dichotomy: inotocin activated the insect inotocin and the human vasopressin V1b receptors, but inhibited the human V1aR. Replacement of Arg8 of inotocin by D-Arg8 led to a potent, stable and competitive V1aR-antagonist ([D-Arg8]-inotocin) with a 3,000-fold binding selectivity for the human V1aR over the other three subtypes, OTR, V1bR and V2R. The Arg8/D-Arg8 ligand-pair was further investigated to gain novel insights into the oxytocin/vasopressin peptide-receptor interaction, which led to the identification of key residues of the receptors that are important for ligand functionality and selectivity. These observations could play an important role for development of oxytocin/vasopressin receptor modulators that would enable clear distinction of the physiological and pathological responses of the individual receptor subtypes.

  13. 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.

  14. Polymorphism of the prolactin gene and its association with egg ...

    African Journals Online (AJOL)

    p2492989

    In this study, polymorphism of the prolactin gene was screened in six Chinese native ... Prolactin (PRL) is a single-chain polypeptide hormone that belongs to the growth hormone gene ..... Enhance the efficiency of single-strand conformation polymorphism analysis by short polyacrylamide gel and modified silver staining.

  15. Mammalian Prolactin – An Ancient But Still A Mysterious Hormone

    Indian Academy of Sciences (India)

    Table of contents. Mammalian Prolactin – An Ancient But Still A Mysterious Hormone · Prolactin inhibits LHRH action during lactational ammenorrhoea · Slide 3 · Slide 4 · REDUCTIONIST VIEW OF HORMONES · CONCERN · PURIFICATION PROTOCOLS · CHARACTERIZATION OF HORMONES · Slide 9 · Slide 10.

  16. Combined receptor antagonist stimulation of the hypothalamic-pituitary-adrenal axis test identifies impaired negative feedback sensitivity to cortisol in obese men.

    Science.gov (United States)

    Mattsson, Cecilia; Reynolds, Rebecca M; Simonyte, Kotryna; Olsson, Tommy; Walker, Brian R

    2009-04-01

    Hypothalamic-pituitary-adrenal (HPA) axis dysregulation may underlie disorders including obesity, depression, cognitive decline, and the metabolic syndrome. Conventional tests of HPA axis negative feedback rely on glucocorticoid receptor (GR) agonists such as dexamethasone but do not test feedback by endogenous cortisol, potentially mediated by both GR and mineralocorticoid receptors (MR). The objective of the study was to use a combination of GR (RU38486, mifepristone) and MR (spironolactone) antagonists to explore the poorly understood activation of the HPA axis that occurs in obesity. This was a double-blind, placebo-controlled, randomized, crossover study. The study was conducted at a clinical research facility. Participants included 15 lean (body mass index 22.0 +/- 1.6 kg/m(2)) and 16 overweight/obese (body mass index 30.1 +/- 3.5 kg/m(2)) men. Subjects attended on four occasions for blood and saliva sampling every 30 min between 1800 and 2200 h. At 1100 and 1600 h before visits, subjects took 200 mg spironolactone, 400 mg RU38486, 200 mg spironolactone + 400 mg RU38486, or placebo orally. Serum cortisol levels after drug or placebo were measured. Cortisol levels did not differ between lean and obese after placebo. Spironolactone and RU38486 alone had modest effects, increasing cortisol by less than 50% in both groups. However, combined spironolactone plus RU38486 elevated cortisol concentrations substantially, more so in lean than obese men [2.9- (0.3) vs. 2.2 (0.3)-fold elevation, P = 0.002]. Combined receptor antagonist stimulation of the HPA axis reveals redundancy of MR and GR in negative feedback in humans. Obese men have impaired responses to combined receptor antagonist stimulation, suggesting impaired negative feedback by endogenous cortisol. Such an approach may be useful to dissect abnormal HPA axis control in neuropsychiatric and other disorders.

  17. The effects of dopamine receptor 1 and 2 agonists and antagonists on sexual and aggressive behaviors in male green anoles.

    Science.gov (United States)

    Smith, Alexandra N; Kabelik, David

    2017-01-01

    The propensity to exhibit social behaviors during interactions with same-sex and opposite-sex conspecifics is modulated by various neurotransmitters, including dopamine. Dopamine is a conserved neurotransmitter among vertebrates and dopaminergic receptors are also highly conserved among taxa. Activation of D1 and D2 dopamine receptor subtypes has been shown to modulate social behaviors, especially in mammalian and avian studies. However, the specific behavioral functions of these receptors vary across taxa. In reptiles there have been few studies examining the relationship between dopaminergic receptors and social behaviors. We therefore examined the effects of D1 and D2 agonists and antagonists on sexual and aggressive behaviors in the male green anole lizard (Anolis carolinensis). Treatment with high doses of both D1 and D2 agonists was found to impair both sexual and aggressive behaviors. However, the D1 agonist treatment was also found to impair motor function, suggesting that those effects were likely nonspecific. Lower doses of both agonists and antagonists failed to affect social behaviors. These findings provide some evidence for D2 receptor regulation of social behaviors, but in contrast with previous research, these effects are all inhibitory and no effects were found for manipulations of D1 receptors. A potential reason for the lack of more widespread effects on social behaviors using moderate or low drug doses is that systemic injection of drugs resulted in effects throughout the whole brain, thus affecting counteracting circuits which negated one another, making measurable changes in behavioral output difficult to detect. Future studies should administer drugs directly into brain regions known to regulate sexual and aggressive behaviors.

  18. The effects of dopamine receptor 1 and 2 agonists and antagonists on sexual and aggressive behaviors in male green anoles.

    Directory of Open Access Journals (Sweden)

    Alexandra N Smith

    Full Text Available The propensity to exhibit social behaviors during interactions with same-sex and opposite-sex conspecifics is modulated by various neurotransmitters, including dopamine. Dopamine is a conserved neurotransmitter among vertebrates and dopaminergic receptors are also highly conserved among taxa. Activation of D1 and D2 dopamine receptor subtypes has been shown to modulate social behaviors, especially in mammalian and avian studies. However, the specific behavioral functions of these receptors vary across taxa. In reptiles there have been few studies examining the relationship between dopaminergic receptors and social behaviors. We therefore examined the effects of D1 and D2 agonists and antagonists on sexual and aggressive behaviors in the male green anole lizard (Anolis carolinensis. Treatment with high doses of both D1 and D2 agonists was found to impair both sexual and aggressive behaviors. However, the D1 agonist treatment was also found to impair motor function, suggesting that those effects were likely nonspecific. Lower doses of both agonists and antagonists failed to affect social behaviors. These findings provide some evidence for D2 receptor regulation of social behaviors, but in contrast with previous research, these effects are all inhibitory and no effects were found for manipulations of D1 receptors. A potential reason for the lack of more widespread effects on social behaviors using moderate or low drug doses is that systemic injection of drugs resulted in effects throughout the whole brain, thus affecting counteracting circuits which negated one another, making measurable changes in behavioral output difficult to detect. Future studies should administer drugs directly into brain regions known to regulate sexual and aggressive behaviors.

  19. Discovery and characterization of ACT-335827, an orally available, brain penetrant orexin receptor type 1 selective antagonist.

    Science.gov (United States)

    Steiner, Michel A; Gatfield, John; Brisbare-Roch, Catherine; Dietrich, Hendrik; Treiber, Alexander; Jenck, Francois; Boss, Christoph

    2013-06-01

    Stress relief: Orexin neuropeptides regulate arousal and stress processing through orexin receptor type 1 (OXR-1) and 2 (OXR-2) signaling. A selective OXR-1 antagonist, represented by a phenylglycine-amide substituted tetrahydropapaverine derivative (ACT-335827), is described that is orally available, penetrates the brain, and decreases fear, compulsive behaviors and autonomic stress reactions in rats. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Pharmacokinetic/pharmaco-dynamic modelling and simulation of the effects of different cannabinoid receptor type 1 antagonists on (9)-tetrahydrocannabinol challenge tests

    NARCIS (Netherlands)

    Guan, Zheng; Klumpers, Linda E.; Oyetayo, Olubukayo-Opeyemi; Heuberger, Jules; van Gerven, Joop M. A.; Stevens, Jasper

    Aim: The severe psychiatric side effects of cannabinoid receptor type 1 (CB1) antagonists hampered their wide development but this might be overcome by careful management of drug development with pharmacokinetic/pharmacodynamic (PK/PD) analyses. PK/PD models suitable for direct comparison of

  1. Current position of 5HT3 antagonists and the additional value of NK1 antagonists; a new class of antiemetics

    NARCIS (Netherlands)

    R. de Wit (Ronald)

    2003-01-01

    textabstractThe advent of the 5HT3 receptor antagonists (5HT3 antagonists) in the 1990s and the combination with dexamethasone has resulted in acute emesis protection in 70% of patients receiving highly emetogenic chemotherapy. Despite complete protection in the acute phase, however, 40% of patients

  2. Effects of chronic alternating cadmium exposure on the episodic secretion of prolactin in male rats

    Energy Technology Data Exchange (ETDEWEB)

    Esquifino, A.I. [Madrid Univ. (Spain). Facultad de Medicina Complutense; Marquez, N.; Alvarez-Demanuel, E.; Lafuente, A. [Vigo Univ., Orense (Spain). Lab. de Toxicologia

    1998-07-01

    Cadmium increases or decreases prolactin secretion depending on the dose and duration of the exposure to the metal. However, whether there are cadmium effects on the episodic prolactin secretion is less well known. This study was undertaken to address whether chronic alternating exposure to two different doses of cadmium affects the episodic pattern of prolactin and to what extent the effects of cadmium are age-dependent. Male rats were treated s.c. with cadmium chloride (0.5 or 1.0 mg/kg) from day 30 to 60, or from day 60 to 90 of age, with alteration of the doses every 4 days, starting with the smaller dose. Controls received vehicle every 4 days. The last dose of cadmium was given 48 h prior to the pulsatility study. Prolactin secretion in the 4 experimental groups studied was episodic and changed significantly after cadmium exposure. Cadmium administration from day 30 to 60 of life significantly decreased the mean half-life of prolactin. On the other hand, when administered from day 60 to 90 cadmium significantly decreased the mean as well as serum prolactin levels and the absolute amplitude of the prolactin pulses, their duration, the relative amplitude or the mean half-life of the hormone. The frequency of prolactin peaks was not changed by cadmium administration. The results indicate that low intermittent doses of cadmium chronically administered change the episodic secretion pattern of prolactin in rats. The effects of cadmium on prolactin secretion were age dependent. (orig.)

  3. Studies on an (S)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor antagonist IKM-159

    DEFF Research Database (Denmark)

    Juknaite, Lina; Sugamata, Yutaro; Tokiwa, Kazuya

    2013-01-01

    IKM-159 was developed and identified as a member of a new class of heterotricyclic glutamate analogs that act as AMPA receptor-selective antagonists. However, it was not known which enantiomer of IKM-159 was responsible for its pharmacological activities. Here, we report in vivo and in vitro neur...

  4. Solid-phase synthesis and pharmacological evaluation of analogues of PhTX-12-A potent and selective nicotinic acetylcholine receptor antagonist

    DEFF Research Database (Denmark)

    Strømgaard, Kristian; Mellor, Ian R; Andersen, Kim

    2002-01-01

    Philanthotoxin-12 (PhTX-12) is a novel potent and selective, noncompetitive antagonist of nicotinic acetylcholine receptors (nAChRs). Homologues of PhTX-12 with 7-11 methylene groups between the primary amino group and the aromatic head-group were synthesized using solid-phase methodology. In vitro...

  5. Amelioration of cold injury-induced cortical brain edema formation by selective endothelin ETB receptor antagonists in mice.

    Directory of Open Access Journals (Sweden)

    Shotaro Michinaga

    Full Text Available Brain edema is a potentially fatal pathological condition that often occurs in stroke and head trauma. Following brain insults, endothelins (ETs are increased and promote several pathophysiological responses. This study examined the effects of ETB antagonists on brain edema formation and disruption of the blood-brain barrier in a mouse cold injury model (Five- to six-week-old male ddY mice. Cold injury increased the water content of the injured cerebrum, and promoted extravasation of both Evans blue and endogenous albumin. In the injury area, expression of prepro-ET-1 mRNA and ET-1 peptide increased. Intracerebroventricular (ICV administration of BQ788 (ETB antagonist, IRL-2500 (ETB antagonist, or FR139317 (ETA antagonist prior to cold injury significantly attenuated the increase in brain water content. Bolus administration of BQ788, IRL-2500, or FR139317 also inhibited the cold injury-induced extravasation of Evans blue and albumin. Repeated administration of BQ788 and IRL-2500 beginning at 24 h after cold injury attenuated both the increase in brain water content and extravasation of markers. In contrast, FR139317 had no effect on edema formation when administrated after cold injury. Cold injury stimulated induction of glial fibrillary acidic protein-positive reactive astrocytes in the injured cerebrum. Induction of reactive astrocytes after cold injury was attenuated by ICV administration of BQ788 or IRL-2500. These results suggest that ETB receptor antagonists may be an effective approach to ameliorate brain edema formation following brain insults.

  6. 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

  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. 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.

  9. Clopidogrel (Plavix®), a P2Y(12) receptor antagonist, inhibits bone cell function in vitro and decreases trabecular bone in vivo

    DEFF Research Database (Denmark)

    Syberg, Susanne; Brandao-Burch, Andrea; Patel, Jessal J

    2012-01-01

    Clopidogrel (Plavix®), a selective P2Y(12) receptor antagonist, is widely prescribed to reduce the risk of heart attack and stroke and acts via the inhibition of platelet aggregation. Accumulating evidence now suggests that extracellular nucleotides, signalling through P2 receptors, play...... a significant role in bone, modulating both osteoblast and osteoclast function. In this study, we investigated the effects of clopidogrel treatment on (1) bone cell formation, differentiation and activity in vitro; and, (2) trabecular and cortical bone parameters in vivo. P2Y(12) receptor expression...

  10. RELATIONSHIP BETWEEN PROLACTIN HORMONE LEVEL, MOLTING AND DUCK EGG PRODUCTION

    Directory of Open Access Journals (Sweden)

    T. Susanti

    2012-09-01

    Full Text Available The aims of this study were to obtain information on the mechanism of molting and the prolactin hormone levels affecting egg production. The study utilized AP (crossbred of Alabio ♂ with Peking ♀ and PA (crossbred of Peking ♂ and Alabio ♀ ducks with a total of 180 birds. The observed variables were the duration of cessation of egg production before and after molting, the prolactin hormone level in the period of molting, the egg production period before and after molting. The data was analyzed using ANOVA, regression and correlation. The results showed that AP crossbred had fewer molting (23.33% compared to PA (50.00%. The mechanism of molting is always preceded by cessation of egg production, molting and relaying. The prolactin hormone concentrations of AP and PA in the period before and after molting were significantly higher than in the period of molting. At the egg production period before molting, the prolactin hormone concentration of AP ducks was higher than the PA ducks. So that the egg production of AP before molting (0-16 weeks was higher than the PA. The egg production of AP was higher than PA, 256.66±6.00 vs 232.22±6.64 eggs for 48 weeks. So it can be concluded that the prolactin hormone affects the molting and egg production.

  11. 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

  12. Synthesis of [18F]-labelled nebivolol as a β1-adrenergic receptor antagonist for PET imaging agent

    International Nuclear Information System (INIS)

    Kim, Taek Soo; Park, Jeong Hoon; Lee, Jun Young; Yang, Seung Dae; Chang, Dong Jo

    2017-01-01

    Selective β 1 -agonist and antagonists are used for the treatment of cardiac diseases including congestive heart failure, angina pectoris and arrhythmia. Selective β 1 -antagonists including nebivolol have high binding affinity on β 1 -adrenergic receptor, not β 2 -receptor mainly expressed in smooth muscle. Nebivolol is one of most selective β 1 -blockers in clinically used β 1 - blockers including atenolol and bisoprolol. We tried to develop clinically useful cardiac PET tracers using a selective β 1 -blocker. Nebivolol is C 2 -symmetric and has two chromane moiety with a secondary amino alcohol and aromatic fluorine. We adopted the general synthetic strategy using epoxide ring opening reaction. Unlike formal synthesis of nebivolol, we prepared two chromane building blocks with fluorine and iodine which was transformed to diaryliodonium salt for labelling of 18 F. Two epoxide building blocks were readily prepared from commercially available chromene carboxylic acids (1, 8). Then, the amino alcohol building block (15) was prepared by ammonolysis of epoxide (14) followed by coupling reaction with the other building block, epoxide (7). Diaryliodonium salt, a precursor for 18 F-aromatic substitution, was synthesized in moderate yield which was readily subjected to 18 F-aromatic substitution to give 18 F-labelled nebivolol

  13. Wake-promoting effects of ONO-4127Na, a prostaglandin DP1 receptor antagonist, in hypocretin/orexin deficient narcoleptic mice.

    Science.gov (United States)

    Sagawa, Yohei; Sato, Masatoshi; Sakai, Noriaki; Chikahisa, Sachiko; Chiba, Shintaro; Maruyama, Takashi; Yamamoto, Junki; Nishino, Seiji

    2016-11-01

    Prostaglandin (PG)D2 is an endogenous sleep substance, and a series of animal studies reported that PGD2 or PGD2 receptor (DP1) agonists promote sleep, while DP1 antagonists promote wakefulness. This suggests the possibility of use of PG DP1 antagonists as wake-promoting compounds. We therefore evaluated the wake-promoting effects of ONO-4127Na, a DP1 antagonist, in a mouse model of narcolepsy (i.e., orexin/ataxin-3 transgenic mice) and compared those to effects of modafinil. ONO-4127Na perfused in the basal forebrain (BF) area potently promoted wakefulness in both wild type and narcoleptic mice, and the wake-promoting effects of ONO-4127Na at 2.93 × 10(-4) M roughly corresponded to those of modafinil at 100 mg/kg (p.o.). The wake promoting effects of ONO-4127Na was observed both during light and dark periods, and much larger effects were seen during the light period when mice slept most of the time. ONO-4127Na, when perfused in the hypothalamic area, had no effects on sleep. We further demonstrated that wake-promoting effects of ONO-4127Na were abolished in DP1 KO mice, confirming that the wake-promoting effect of ONO-4127Na is mediated by blockade of the PG DP1 receptors located in the BF area. ONO-4127Na reduced DREM, an EEG/EMG assessment of behavioral cataplexy in narcoleptic mice, suggesting that ONO-4127Na is likely to have anticataplectic effects. DP1 antagonists may be a new class of compounds for the treatment of narcolepsy-cataplexy, and further studies are warranted. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. 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.

  15. 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.

  16. Adenosine AA Receptor Antagonists Do Not Disrupt Rodent Prepulse Inhibition: An Improved Side Effect Profile in the Treatment of Parkinson's Disease

    Directory of Open Access Journals (Sweden)

    Carina J. Bleickardt

    2012-01-01

    Full Text Available Parkinson's disease (PD is characterized by loss of dopaminergic neurons in the substantia nigra. Current treatments for PD focus on dopaminergic therapies, including L-dopa and dopamine receptor agonists. However, these treatments induce neuropsychiatric side effects. Psychosis, characterized by delusions and hallucinations, is one of the most serious such side effects. Adenosine A2A receptor antagonism is a nondopaminergic treatment for PD with clinical and preclinical efficacy. The present studies assessed A2A antagonists SCH 412348 and istradefylline in rodent prepulse inhibition (PPI, a model of psychosis. Dopamine receptor agonists pramipexole (0.3–3 mg/kg, pergolide (0.3–3 mg/kg, and apomorphine (0.3–3 mg/kg significantly disrupted PPI; ropinirole (1–30 mg/kg had no effect; L-dopa (100–300 mg/kg disrupted rat but not mouse PPI. SCH 412348 (0.3–3 mg/kg did not disrupt rodent PPI; istradefylline (0.1–1 mg/kg marginally disrupted mouse but not rat PPI. These results suggest that A2A antagonists, unlike dopamine agonists, have an improved neuropsychiatric side effect profile.

  17. Obtention of antibodies anti prolactin from human prolactin of national production; Obtencion de anticuerpos anti-prolactina a partir de prolactina humana de produccion nacional

    Energy Technology Data Exchange (ETDEWEB)

    Caso, R; Mosquera, M [Centro de Isotopos, La Habana (Cuba); Perez, E [Centro de Investigaciones de Mejoramiento Animal, La Habana (Cuba); Amanz, C [Instituto Nacional de Endocrinologia, La Habana (Cuba)

    1996-07-01

    In this work was studied the use of the the Prolactin hormone as immuno gen, which is obtained in Cuba by the pharmaceutical institute Mario Munoz, to produce the antibody antiprolactin. Was made the validation of obtained antibody (tritatium, specificity and affinity) The produced antibody had necessary quality to be use as a component of the Kits-RIA Prolactin.

  18. ACTIONS OF PROLACTIN IN THE BRAIN: FROM PHYSIOLOGICAL ADAPTATIONS TO STRESS AND NEUROGENESIS TO PSYCHOPATHOLOGY

    Directory of Open Access Journals (Sweden)

    Luz eTorner

    2016-03-01

    Full Text Available Prolactin is one of the most versatile hormones known. It is considered an adaptive hormone due to the key roles it plays in the modulation of the stress response and during pregnancy and lactation. Within the brain, prolactin acts as a neuropeptide to promote physiological responses related to reproduction, stress adaptation, neurogenesis, and neuroprotection. The action of prolactin on the nervous system contributes to the wide array of changes that occur in the female brain during pregnancy and result in the attenuation of the hypothalamic pituitary adrenal axis. Together, all these changes promote behavioral and physiological adaptations of the new mother to enable reproductive success. Brain adaptations driven by prolactin are also important for the regulation of maternal emotionality and wellbeing Prolactin also affects the male brain during the stress response but its effects have been less studied. Prolactin regulates neurogenesis both in the subventricular zone and in the hippocampus. Therefore, alterations in the prolactin system due to stress, or exposure to substances that reduce neurogenesis or other conditions, could contribute to maladaptive responses and pathological behavioral outcomes. Here we review the prolactin system and the role it plays in the modulation of stress response and emotion regulation. We discuss the effects of prolactin on neurogenesis and neuroprotection, the putative neuronal mechanisms underlying these effects, and their contribution to the onset of psychopathological states like depression.

  19. 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.

  20. Brain penetrant small molecule 18F-GnRH receptor (GnRH-R) antagonists: Synthesis and preliminary positron emission tomography imaging in rats

    International Nuclear Information System (INIS)

    Olberg, Dag E.; Bauer, Nadine; Andressen, Kjetil W.; Hjørnevik, Trine; Cumming, Paul; Levy, Finn O.; Klaveness, Jo; Haraldsen, Ira; Sutcliffe, Julie L.

    2016-01-01

    Introduction: The gonadotropin releasing hormone receptor (GnRH-R) has a well-described neuroendocrine function in the anterior pituitary. However, little is known about its function in the central nervous system (CNS), where it is most abundantly expressed in hippocampus and amygdala. Since peptide ligands based upon the endogenous decapetide GnRH do not pass the blood–brain-barrier, we are seeking a high-affinity small molecule GnRH-R ligand suitable for brain imaging by positron emission tomography. We have previously reported the radiosynthesis and in vitro evaluation of two novel [ 18 F]fluorinated GnRH-R ligands belonging to the furamide class of antagonists, with molecular weight less than 500 Da. We now extend this work using palladium coupling for the synthesis of four novel radioligands, with putatively reduced polar surface area and hydrophilicity relative to the two previously described compounds, and report the uptake of these 18 F-labeled compounds in brain of living rats. Methods: We synthesized reference standards of the small molecule GnRH-R antagonists as well as mesylate precursors for 18 F-labeling. The antagonists were tested for binding affinity for both human and rat GnRH-R. Serum and blood stability in vitro and in vivo were studied. Biodistribution and PET imaging studies were performed in male rats in order to assess brain penetration in vivo. Results: A palladium coupling methodology served for the synthesis of four novel fluorinated furamide GnRH receptor antagonists with reduced heteroatomic count. Radioligand binding assays in vitro revealed subnanomolar affinity of the new fluorinated compounds for both human and rat GnRH-R. The 18 F-GnRH antagonists were synthesized from the corresponding mesylate precursors in 5–15% overall radiochemical yield. The radiolabeled compounds demonstrated good in vivo stability. PET imaging with the 18 F-radiotracers in naive rats showed good permeability into brain and rapid washout, but absence of

  1. Follow-up of prolactin levels in patients with breast cancer metastases treated by cryohypophysectomy

    International Nuclear Information System (INIS)

    Rozsival, V.; Petr, R.; Kubicek, J.; Hajek, P.; Fingerova, H.; Talas, M.; Janouskova, M.

    1981-01-01

    In the years 1977 to 1979, prolactin levels were examined in the blood of 39 patients with breast cancer metastases in the skeleton. In 27 patients undergoing surgery, prolactin values were obtained prior to the operation and on the 7th day after stereotactic cryohypophysectomy; in 19 patients the values were obtained also at later intervals. Prolactin was examined using RIA. Prior to surgery, the prolactin levels ranged between 4.3 and above 100 μg/l, with an average of 24.69. Seven days after cryohypophysectomy, the average was 14.01 μg/l, i.e., a remarkable decrease was observed showing considerable significance in the pair test. Prolactin examination in patients with breast cancer metastases showed increased levels above the menopausal standard in almost 80% of the group of patients prior to hypophysectomy. After surgery, a prolactin level decrease was observed in 60% of patients, which confirmed that the intervention in the hypophysis was effective. (author)

  2. Panicolytic-like effects caused by substantia nigra pars reticulata pretreatment with low doses of endomorphin-1 and high doses of CTOP or the NOP receptors antagonist JTC-801 in male Rattus norvegicus.

    Science.gov (United States)

    da Silva, Juliana Almeida; Biagioni, Audrey Franceschi; Almada, Rafael Carvalho; de Freitas, Renato Leonardo; Coimbra, Norberto Cysne

    2017-10-01

    Gamma-aminobutyric acid (GABA)ergic neurons of the substantia nigra pars reticulata (SNpr) are connected to the deep layers of the superior colliculus (dlSC). The dlSC, in turn, connect with the SNpr through opioid projections. Nociceptin/orphanin FQ peptide (N/OFQ) is a natural ligand of a Gi protein-coupled nociceptin receptor (ORL1; NOP) that is also found in the SNpr. Our hypothesis is that tectonigral opioid pathways and intranigral orphanin-mediated mechanisms modulate GABAergic nigrotectal connections. Therefore, the aim of this work was to study the role of opioid and NOP receptors in the SNpr during the modulation of defence reactions organised by the dlSC. The SNpr was pretreated with either opioid or NOP receptor agonists and antagonists, followed by dlSC treatment with bicuculline. Blockade of GABA A receptors in the dlSC elicited fear-related defensive behaviour. Pretreatment of the SNpr with naloxone benzoylhydrazone (NalBzoH), a μ-, δ-, and κ 1 -opioid receptor antagonist as well as a NOP receptor antagonist, decreased the aversive effect of bicuculline treatment on the dlSC. Either μ-opioid receptor activation or blockade by SNpr microinjection of endomorphin-1 (EM-1) and CTOP promoted pro-aversive and anti-aversive actions, respectively, that modulated the defensive responses elicited by bicuculline injection into the dlSC. Pretreatment of the SNpr with the selective NOP receptor antagonist JTC801 decreased the aversive effect of bicuculline, and microinjections of the selective NOP receptor agonist NNC 63-0532 promoted the opposite effect. These results demonstrate that opioid pathways and orphanin-mediated mechanisms have a critical role in modulating the activity of nigrotectal GABAergic pathways during the organisation of defensive behaviours.

  3. SERUM PROLACTIN LEVEL IN ACNE PATIENTS VERSUS CONTROL GROUP: STUDY ON 14 TO 35 YEARS OLD WOMEN

    Directory of Open Access Journals (Sweden)

    G FAGHIHI

    2002-03-01

    Full Text Available Introduction. Androgens have a main role in acne pathogenesis. The interaction between prolactin and androgens generate the hypothesis of prolactin role in acne pathogenesis. Methods. In a case - control study, 71 women with modearte to severe acne were compaired with 71 healthy women about their serum prolactin levels. Results. Mean of serum prolactin level was 533 632 miu/lit in cases. Mean of serum prolactin level was 365 363 in control group (P > 0.05. There was a significant correlation between serum prolactin level and severity of acne. Discussion. Despite the non significant difference between serum prolactin level in acne patients and healthy women, thare was a significant relationship between serum prolactin level and severity of acne. It may be due to our small sample size. However, the more powerful studies is needed.

  4. GHRH excess and blockade in X-LAG syndrome.

    Science.gov (United States)

    Daly, Adrian F; Lysy, Philippe A; Desfilles, Céline; Rostomyan, Liliya; Mohamed, Amira; Caberg, Jean-Hubert; Raverot, Veronique; Castermans, Emilie; Marbaix, Etienne; Maiter, Dominique; Brunelle, Chloe; Trivellin, Giampaolo; Stratakis, Constantine A; Bours, Vincent; Raftopoulos, Christian; Beauloye, Veronique; Barlier, Anne; Beckers, Albert

    2016-03-01

    X-linked acrogigantism (X-LAG) syndrome is a newly described form of inheritable pituitary gigantism that begins in early childhood and is usually associated with markedly elevated GH and prolactin secretion by mixed pituitary adenomas/hyperplasia. Microduplications on chromosome Xq26.3 including the GPR101 gene cause X-LAG syndrome. In individual cases random GHRH levels have been elevated. We performed a series of hormonal profiles in a young female sporadic X-LAG syndrome patient and subsequently undertook in vitro studies of primary pituitary tumor culture following neurosurgical resection. The patient demonstrated consistently elevated circulating GHRH levels throughout preoperative testing, which was accompanied by marked GH and prolactin hypersecretion; GH demonstrated a paradoxical increase following TRH administration. In vitro, the pituitary cells showed baseline GH and prolactin release that was further stimulated by GHRH administration. Co-incubation with GHRH and the GHRH receptor antagonist, acetyl-(d-Arg(2))-GHRH (1-29) amide, blocked the GHRH-induced GH stimulation; the GHRH receptor antagonist alone significantly reduced GH release. Pasireotide, but not octreotide, inhibited GH secretion. A ghrelin receptor agonist and an inverse agonist led to modest, statistically significant increases and decreases in GH secretion, respectively. GHRH hypersecretion can accompany the pituitary abnormalities seen in X-LAG syndrome. These data suggest that the pathology of X-LAG syndrome may include hypothalamic dysregulation of GHRH secretion, which is in keeping with localization of GPR101 in the hypothalamus. Therapeutic blockade of GHRH secretion could represent a way to target the marked hormonal hypersecretion and overgrowth that characterizes X-LAG syndrome. © 2016 Society for Endocrinology.

  5. Monepantel is a non-competitive antagonist of nicotinic acetylcholine receptors from Ascaris suum and Oesophagostomum dentatum

    Directory of Open Access Journals (Sweden)

    Melanie Abongwa

    2018-04-01

    Full Text Available Zolvix® is a recently introduced anthelmintic drench containing monepantel as the active ingredient. Monepantel is a positive allosteric modulator of DEG-3/DES-2 type nicotinic acetylcholine receptors (nAChRs in several nematode species. The drug has been r