Effects of exercise training and exhaustion on 45Ca uptake by rat skeletal muscle mitochondria and sarcoplasmic reticulum

International Nuclear Information System (INIS)

Bonner, H.W.; Leslie, S.W.; Combs, A.B.; Tate, C.A.

1976-01-01

Mitochondrial and sarcoplasmic reticular 45 Ca 2+ uptake and Ca 2+ -ATPase activity were determined in skeletal muscle from exercise trained and non-trained rats at rest or following short-term exhaustive exercise. In trained rats exercised to exhaustion, mitochondrial 45 Ca 2+ uptake was significantly depressed when compared to non-trained rats at rest. Ca 2+ -ATPase activity of sarcoplasmic reticulum from trained rats exercised to exhaustion was significantly increased as compared to trained rats at rest. These data suggest that the disruptive influence of Ca 2+ accumulation in mitochondria isolated following exhaustive exercise may be diminished as a result of training

Evaluation of the Ca2+ distribution in aortic tissue of spontaneously hypertensive and normotensive rats

International Nuclear Information System (INIS)

Spieker, C.; Zidek, W.; von Bassewitz, D.B.; Heck, D.; Rahn, K.H.

1991-01-01

In the present study, particle-induced X-ray emission (PIXE) was used to get information on the spatial distribution of Ca 2+ in aortas of spontaneously hypertensive rats (SHR) and normotensive controls aged 1 week, 4 weeks, and 12 weeks. To differentiate changes in Ca 2+ metabolism in hypertensive arteries from secondary phenomena due to the arteriosclerosis, the animals were examined in the earliest stage of hypertension. It was found that the Ca 2+ content was not elevated in the aortic smooth muscle of SHR aged 1 week (n = 11), as compared to normotensive controls (n = 10) (186.8 +/- 89.9 micrograms Ca 2+ /g tissue v 254.0 +/- 173.3 micrograms Ca 2+ /g). The Ca 2+ content was raised (P less than .05) in the aortic smooth muscle of SHR aged 4 weeks (n = 13), as compared to 12 WKY rats (4 weeks) (726.0 +/- 130.4 micrograms Ca 2+ /g tissue v 440.3 +/- 214.4 micrograms Ca 2+ /g) and in 17 SHR (3 months), as compared to 13 WKY rats, respectively (3390.1 +/- 729.9 micrograms Ca 2+ /g tissue v 1632.1 +/- 569.5 micrograms Ca 2+ /g). The results confirm the age-related increase in the arterial Ca 2+ content in normotensive rats and demonstrate additionally that this age-related rise in arterial Ca 2+ content is accelerated in SHR

Calcium metabolism in the rat: A temporal self-organized model

International Nuclear Information System (INIS)

Staub, J.F.; Tracqui, P.; Brezillon, P.; Milhaud, G.; Perault-Staub, A.M.

1988-01-01

Based on consideration of rat plasma Ca and 45 Ca concentrations, the authors analyze the circadian behavior of Ca metabolism of the rat as the temporal expression of a self-organized system. They present a self-oscillatory model M for rat Ca metabolism based on a compartmental formalism, which includes a second-order autocatalytic process. M describes the entire mass of Ca as made up of eight compartments and predicts a distinction between (1) the amount of Ca deposited in zones of rapid bone growth and reutilized during bone maturation and (2) the amount of Ca in mature bone subdivided into four compartments. Two of these compartments, largely self-oscillating, may represent Ca-P associations at bone liquid/solid interface and are subject to osteoblast-osteocyte control. The other two compartments can be thought of as made up of a large expanding pool of hydroxyapatite (HA) crystals, which are largely unavailable as such, and a small pool of more available HA crystals. Bone Ca influx and rhythmic efflux play a major role in the regulation of Ca in extracellular fluid but must be dissociated from bone accretion and resorption. Application to Ca deficiency was analyzed. Conceptual consequences of the connection of Ca metabolism to a self-regulated system are discussed

Cytomorphometric changes in hippocampal CA1 neurons exposed to simulated microgravity using rats as model

Directory of Open Access Journals (Sweden)

Amit eRanjan

2014-05-01

Full Text Available Microgravity and sleep loss lead to cognitive and learning deficits. These behavioral alterations are likely to be associated with cytomorphological changes and loss of neurons. To understand the phenomenon, we exposed rats (225-275g to 14 days simulated microgravity (SMg and compared its effects on CA1 hippocampal neuronal plasticity, with that of normal cage control rats. We observed that the mean area, perimeter, synaptic cleft and length of active zone of CA1 hippocampal neurons significantly decreased while dendritic arborization and number of spines significantly increased in SMg group as compared with controls. The mean thickness of the post synaptic density and total dendritic length remained unaltered. The changes may be a compensatory effect induced by exposure to microgravity; however, the effects may be transient or permanent, which need further study. These findings may be useful for designing effective prevention for those, including the astronauts, exposed to microgravity. Further, subject to confirmation we propose that SMg exposure might be useful for recovery of stroke patients.

Acupuncture attenuates cognitive deficits and increases pyramidal neuron number in hippocampal CA1 area of vascular dementia rats.

Science.gov (United States)

Li, Fang; Yan, Chao-Qun; Lin, Li-Ting; Li, Hui; Zeng, Xiang-Hong; Liu, Yi; Du, Si-Qi; Zhu, Wen; Liu, Cun-Zhi

2015-04-28

Decreased cognition is recognized as one of the most severe and consistent behavioral impairments in dementia. Experimental studies have reported that acupuncture may improve cognitive deficits, relieve vascular dementia (VD) symptoms, and increase cerebral perfusion and electrical activity. Multi-infarction dementia was modeled in rats with 3% microemboli saline suspension. Two weeks after acupuncture at Zusanli (ST36), all rats were subjected to a hidden platform trial to test their 3-day spatial memory using the Morris water maze test. To estimate the numbers of pyramidal neuron, astrocytes, and synaptic boutons in hippocampal CA1 area, we adopted an unbiased stereology method to accurately sample and measure the size of cells. We found that acupuncture at ST36 significantly decreased the escape latency of VD rats. In addition, acupuncture significantly increased the pyramidal neuron number in hippocampal CA1 area (P area in any of the groups (P > 0.05). These findings suggest that acupuncture may improve cognitive deficits and increase pyramidal neuron number of hippocampal CA1 area in VD rats.

Increased transfer of 45Ca into brain and cerebrospinal fluid from plasma during chronic hypocalcemia in rats.

Science.gov (United States)

Murphy, V A; Rapoport, S I

1988-06-28

Recent studies have shown regulation of central nervous system [Ca] after chronic hypo- and hypercalcemia. To investigate the mechanism of this regulation, 3-week-old rats were fed diets for 8 weeks that contained low or normal levels of Ca. Plasma [Ca] was 40% less in rats fed the low Ca diet than in animals fed normal diet. Unidirectional transfer coefficients for Ca (KCa) and Cl (KCl) into cerebrospinal fluid (CSF) and brain were determined from the 10 min uptake of intravenously injected 45Ca and 36Cl in awake animals. KCa for CSF was 68% greater in low-Ca rats than in normal rats. Likewise, the values of KCa for brain regions with areas adjacent to the ventricles like the hippocampus and pons-medulla were 50% higher than in normal animals. On the other hand, KCas for parietal cortex, a brain region distant from the choroid plexus and not expected to be influenced by Ca entry into CSF, were similar between the groups. Comparison of the regional ratios of KCa/KCl revealed that a selective increase of Ca transport occurred into CSF and all brain regions except the parietal cortex in Ca-deficient rats. The results suggest that Ca homeostasis of CSF and brain [Ca] during chronic hypocalcemia is due to increased transfer of Ca from blood to brain, and that the regulation occurs via the CSF, possibly at the choroid plexus, but not via the cerebral capillaries.

Nifedipine-activated Ca(2+) permeability in newborn rat cortical collecting duct cells in primary culture.

Science.gov (United States)

Valencia, L; Bidet, M; Martial, S; Sanchez, E; Melendez, E; Tauc, M; Poujeol, C; Martin, D; Namorado, M D; Reyes, J L; Poujeol, P

2001-05-01

To characterize Ca(2+) transport in newborn rat cortical collecting duct (CCD) cells, we used nifedipine, which in adult rat distal tubules inhibits the intracellular Ca(2+) concentration ([Ca(2+)](i)) increase in response to hormonal activation. We found that the dihydropyridine (DHP) nifedipine (20 microM) produced an increase in [Ca(2+)](i) from 87.6 +/- 3.3 nM to 389.9 +/- 29.0 nM in 65% of the cells. Similar effects of other DHP (BAY K 8644, isradipine) were also observed. Conversely, DHPs did not induce any increase in [Ca(2+)](i) in cells obtained from proximal convoluted tubule. In CCD cells, neither verapamil nor diltiazem induced any rise in [Ca(2+)](i). Experiments in the presence of EGTA showed that external Ca(2+) was required for the nifedipine effect, while lanthanum (20 microM), gadolinium (100 microM), and diltiazem (20 microM) inhibited the effect. Experiments done in the presence of valinomycin resulted in the same nifedipine effect, showing that K(+) channels were not involved in the nifedipine-induced [Ca(2+)](i) rise. H(2)O(2) also triggered [Ca(2+)](i) rise. However, nifedipine-induced [Ca(2+)](i) increase was not affected by protamine. In conclusion, the present results indicate that 1) primary cultures of cells from terminal nephron of newborn rats are a useful tool for investigating Ca(2+) transport mechanisms during growth, and 2) newborn rat CCD cells in primary culture exhibit a new apical nifedipine-activated Ca(2+) channel of capacitive type (either transient receptor potential or leak channel).

Single molecular image of cytosolic free Ca2+ of skeletal muscle cells in rats pre- and post-exercise-induced fatigue

Science.gov (United States)

Liu, Yi; Zhang, Heming; Zhao, Yanping; Liu, Zhiming

2009-08-01

A growing body of literature indicated the cytosolic free Ca2+ concentration of skeletal muscle cells changes significantly during exercise-induced fatigue. But it is confusing whether cytosolic free Ca2+ concentration increase or decrease. Furthermore, current researches mainly adopt muscle tissue homogenate as experiment material, but the studies based on cellular and subcellular level is seldom. This study is aimed to establish rat skeletal muscle cell model of exercise-induced fatigue, and confirm the change of cytosolic free Ca2+ concentration of skeletal muscle cells in rats preand post- exercise-induced fatigue. In this research, six male Wistar rats were randomly divided into two groups: control group (n=3) and exercise-induced fatigue group (n=3). The former group were allowed to freely move and the latter were forced to loaded swimming to exhaustive. Three days later, all the rats were sacrificed, the muscle tissue from the same site of skeletal muscle were taken out and digested to cells. After primary culture of the two kinds of skeletal muscle cells from tissue, a fluorescent dye-Fluo-3 AM was used to label the cytosolic free Ca2+. The fluorescent of Ca2+ was recorded by confocal laser scanning microscopy. The results indicated that, the Ca2+ fluorescence intensity of cells from the rat of exercise-induced fatigue group was significantly higher than those in control group. In conclusion, cytosolic free Ca2+ concentration of skeletal muscle cells has a close relation with exercise-induced fatigue, and the increase of cytosolic free Ca2+ concentration may be one of the important factors of exercise-induced fatigue.

Deficits in synaptic function occur at medial perforant path-dentate granule cell synapses prior to Schaffer collateral-CA1 pyramidal cell synapses in the novel TgF344-Alzheimer's Disease Rat Model.

Science.gov (United States)

Smith, Lindsey A; McMahon, Lori L

2018-02-01

Alzheimer's disease (AD) pathology begins decades prior to onset of clinical symptoms, and the entorhinal cortex and hippocampus are among the first and most extensively impacted brain regions. The TgF344-AD rat model, which more fully recapitulates human AD pathology in an age-dependent manner, is a next generation preclinical rodent model for understanding pathophysiological processes underlying the earliest stages of AD (Cohen et al., 2013). Whether synaptic alterations occur in hippocampus prior to reported learning and memory deficit is not known. Furthermore, it is not known if specific hippocampal synapses are differentially affected by progressing AD pathology, or if synaptic deficits begin to appear at the same age in males and females in this preclinical model. Here, we investigated the time-course of synaptic changes in basal transmission, paired-pulse ratio, as an indirect measure of presynaptic release probability, long-term potentiation (LTP), and dendritic spine density at two hippocampal synapses in male and ovariectomized female TgF344-AD rats and wildtype littermates, prior to reported behavioral deficits. Decreased basal synaptic transmission begins at medial perforant path-dentate granule cell (MPP-DGC) synapses prior to Schaffer-collateral-CA1 (CA3-CA1) synapses, in the absence of a change in paired-pulse ratio (PPR) or dendritic spine density. N-methyl-d-aspartate receptor (NMDAR)-dependent LTP magnitude is unaffected at CA3-CA1 synapses at 6, 9, and 12months of age, but is significantly increased at MPP-DGC synapses in TgF344-AD rats at 6months only. Sex differences were only observed at CA3-CA1 synapses where the decrease in basal transmission occurs at a younger age in males versus females. These are the first studies to define presymptomatic alterations in hippocampal synaptic transmission in the TgF344-AD rat model. The time course of altered synaptic transmission mimics the spread of pathology through hippocampus in human AD and provides

In vitro model to study the effects of matrix stiffening on Ca2+ handling and myofilament function in isolated adult rat cardiomyocytes.

Science.gov (United States)

van Deel, Elza D; Najafi, Aref; Fontoura, Dulce; Valent, Erik; Goebel, Max; Kardux, Kim; Falcão-Pires, Inês; van der Velden, Jolanda

2017-07-15

This paper describes a novel model that allows exploration of matrix-induced cardiomyocyte adaptations independent of the passive effect of matrix rigidity on cardiomyocyte function. Detachment of adult cardiomyocytes from the matrix enables the study of matrix effects on cell shortening, Ca 2+ handling and myofilament function. Cell shortening and Ca 2+ handling are altered in cardiomyocytes cultured for 24 h on a stiff matrix. Matrix stiffness-impaired cardiomyocyte contractility is reversed upon normalization of extracellular stiffness. Matrix stiffness-induced reduction in unloaded shortening is more pronounced in cardiomyocytes isolated from obese ZSF1 rats with heart failure with preserved ejection fraction compared to lean ZSF1 rats. Extracellular matrix (ECM) stiffening is a key element of cardiac disease. Increased rigidity of the ECM passively inhibits cardiac contraction, but if and how matrix stiffening also actively alters cardiomyocyte contractility is incompletely understood. In vitro models designed to study cardiomyocyte-matrix interaction lack the possibility to separate passive inhibition by a stiff matrix from active matrix-induced alterations of cardiomyocyte properties. Here we introduce a novel experimental model that allows exploration of cardiomyocyte functional alterations in response to matrix stiffening. Adult rat cardiomyocytes were cultured for 24 h on matrices of tuneable stiffness representing the healthy and the diseased heart and detached from their matrix before functional measurements. We demonstrate that matrix stiffening, independent of passive inhibition, reduces cell shortening and Ca 2+ handling but does not alter myofilament-generated force. Additionally, detachment of adult cultured cardiomyocytes allowed the transfer of cells from one matrix to another. This revealed that stiffness-induced cardiomyocyte changes are reversed when matrix stiffness is normalized. These matrix stiffness-induced changes in cardiomyocyte

Different Densities of Na-Ca Exchange Current in T-Tubular and Surface Membranes and Their Impact on Cellular Activity in a Model of Rat Ventricular Cardiomyocyte

Czech Academy of Sciences Publication Activity Database

Pásek, Michal; Šimurda, J.; Christé, G.

2017-01-01

Roč. 2017, č. 2017 (2017), č. článku 6343821. ISSN 2314-6133 Institutional support: RVO:61388998 Keywords : rat ventricular cell * mathematical model * Na-Ca current * t-tubules Subject RIV: BO - Biophysics OBOR OECD: Biophysics Impact factor: 2.476, year: 2016

1,25(OH)2D3 and Ca-binding protein in fetal rats: Relationship to the maternal vitamin D status

International Nuclear Information System (INIS)

Verhaeghe, J.; Thomasset, M.; Brehier, A.; Van Assche, F.A.; Bouillon, R.

1988-01-01

The autonomy and functional role of fetal 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ] were investigated in nondiabetic and diabetic BB rats fed diets containing 0.85% calcium-0.7% phosphorus or 0.2% calcium and phosphorus and in semistarved rats on the low calcium-phosphorus diet. The changes in maternal and fetal plasma 1,25(OH) 2 D 3 were similar: the levels were increased by calcium-phosphorus restriction and decreased by diabetes and semistarvation. Maternal and fetal 1,25(OH) 2 D 3 levels were correlated. The vitamin D-dependent calcium-binding proteins (CaBP 9K and CaBP 28K ) were measured in multiple maternal and fetal tissues and in the placenta of nondiabetic, diabetic, and calcium-phosphorus-restricted rats. The distributions of CaBP 9K and CaBP 28K in the pregnant rat were similar to that of the growing rat. The increased maternal plasma 1,25(OH) 2 D 3 levels in calcium-phosphorus-restricted rats were associated with higher duodenal CaBP 9K and renal CaBPs, but placental CaBP 9K was not different. In diabetic pregnant rats, duodenal CaBP 9K was not different. In diabetic pregnant rats, duodenal CaBP 9K tended to be lower, while renal CaBPs were normal; placental CaBP 9K was decreased. The results indicate that in the rat fetal 1,25(OH) 2 D 3 depends on maternal 1,25(OH) 2 D 3 or on factors regulating maternal 1,25(OH) 2 D 3 . The lack of changes in fetal CaBP in the presence of altered fetal plasma 1,25(OH) 2 D 3 levels confirms earlier data showing that 1,25(H) 2 D 3 has a limited hormonal function during perinatal development in the rat

Renal hypertension prevents run training modification of cardiomyocyte diastolic Ca2+ regulation in male rats.

Science.gov (United States)

Palmer, B M; Lynch, J M; Snyder, S M; Moore, R L

2001-06-01

The combined effects of endurance run training and renal hypertension on cytosolic Ca2+ concentration ([Ca2+]c) dynamics and Na+-dependent Ca2+ regulation in rat left ventricular cardiomyocytes were examined. Male Fischer 344 rats underwent stenosis of the left renal artery [hypertensive (Ht), n = 18] or a sham operation [normotensive (Nt), n = 20]. One-half of the rats from each group were treadmill trained for >16 wk. Cardiomyocyte fura 2 fluorescence ratio transients were recorded for 7 min during electrical pacing at 0.5 Hz, 2 mM extracellular Ca2+ concentration, and 29 degrees C. The rate of [Ca2+]c decline was not changed by run training in the Nt group but was reduced in the Ht group. At 7 min, cardiomyocytes were exposed to 10 mM caffeine in the absence of Na+ and Ca2+, which triggered sarcoplasmic reticular Ca2+ release and suppressed Ca2+ efflux via Na+/Ca2+ exchanger. External Na+ was then added, and Na+-dependent Ca2+ efflux rate was recorded. Treadmill training significantly enhanced Na+-dependent Ca2+ efflux rate under these conditions in the Nt group but not in the Ht group. These data provide evidence that renal hypertension prevents the normal run training-induced modifications in diastolic [Ca2+]c regulation mechanisms, including Na+/Ca2+ exchanger.

Temperature dependence of intracellular Ca2+ homeostasis in rat meiotic and postmeiotic spermatogenic cells.

Science.gov (United States)

Herrera, E; Salas, K; Lagos, N; Benos, D J; Reyes, J G

2001-10-01

The hypothesis that intracellular [Ca2+] is a cell parameter responsive to extreme temperatures in rat meiotic and postmeiotic spermatogenic cells was tested using intracellular fluorescent probes for Ca2+ and pH. In agreement with this hypothesis, extreme temperatures induced a rapid increase of cytosolic [Ca2+] in rat pachytene spermatocytes and round spermatids. Oscillatory changes in temperature can induce oscillations in cytosolic [Ca2+] in these cells. Intracellular [Ca2+] homeostasis in round spermatids was more sensitive to high temperatures compared with pachytene spermatocytes. The calculated activation energies for SERCA ATPase-mediated fluxes in pachytene spermatocytes and round spermatids were 62 and 75 kJ mol(-1), respectively. The activation energies for leak fluxes from intracellular Ca2+ stores were 55 and 68 kJ mol(-1) for pachytene spermatocytes and round spermatids, respectively. Together with changes in cytosolic [Ca2+], round spermatids undergo a decrease in pH(i) at high temperatures. This temperature-induced decrease in pH(i) appears to be partially responsible for the increase in cytosolic [Ca2+] of round spermatids induced by high temperatures. This characteristic of rat meiotic and postmeiotic spermatogenic cells to undergo an increment in cytosolic Ca2+ at temperatures > 33 degrees C can be related to the induction of programmed cell death by high temperatures in these cells.

Model of excitation-contraction coupling of rat neonatal ventricular myocytes.

Science.gov (United States)

Korhonen, Topi; Hänninen, Sandra L; Tavi, Pasi

2009-02-01

The neonatal rat ventricular myocyte culture is one of the most popular experimental cardiac cell models. To our knowledge, the excitation-contraction coupling (ECC) of these cells, i.e., the process linking the electrical activity to the cytosolic Ca2+ transient and contraction, has not been previously analyzed, nor has it been presented as a complete system in detail. Neonatal cardiomyocytes are in the postnatal developmental stage, and therefore, the features of their ECC differ vastly from those of adult ventricular myocytes. We present the first complete analysis of ECC in these cells by characterizing experimentally the action potential and calcium signaling and developing the first mathematical model of ECC in neonatal cardiomyocytes that we know of. We show that in comparison to adult cardiomyocytes, neonatal cardiomyocytes have long action potentials, heterogeneous cytosolic Ca2+ signals, weaker sarcoplasmic reticulum Ca2+ handling, and stronger sarcolemmal Ca2+ handling, with a significant contribution by the Na+/Ca2+ exchanger. The developed model reproduces faithfully the ECC of rat neonatal cardiomyocytes with a novel description of spatial cytosolic [Ca2+] signals. Simulations also demonstrate how an increase in the cell size (hypertrophy) affects the ECC in neonatal cardiomyocytes. This model of ECC in developing cardiomyocytes provides a platform for developing future models of cardiomyocytes at different developmental stages.

Intercellular communication within the rat anterior pituitary gland. XV. Properties of spontaneous and LHRH-induced Ca2+ transients in the transitional zone of the rat anterior pituitary in situ.

Science.gov (United States)

Hattori, Kazuki; Shirasawa, Nobuyuki; Suzuki, Hikaru; Otsuka, Takanobu; Wada, Ikuo; Yashiro, Takashi; Herbert, Damon C; Soji, Tsuyoshi; Hashitani, Hikaru

2013-01-01

In the transitional zone of the rat anterior pituitary, spontaneous and LHRH-induced Ca(2+) dynamics were visualized using fluo-4 fluorescence Ca(2+) imaging. A majority of cells exhibited spontaneous Ca(2+) transients, while small populations of cells remained quiescent. Approximately 70% of spontaneously active cells generated fast, oscillatory Ca(2+) transients that were inhibited by cyclopiazonic acid (10 μm) but not nicardipine (1 μm), suggesting that Ca(2+) handling by endoplasmic reticulum, but not Ca(2+) influx through voltage-dependent L-type Ca(2+) channels, plays a fundamental role in their generation. In the adult rat anterior pituitary, LHRH (100 μg/ml) caused a transient increase in the Ca(2+) level in a majority of preparations taken from the morning group rats killed between 0930 h and 1030 h. However, the second application of LHRH invariably failed to elevate Ca(2+) levels, suggesting that the long-lasting refractoriness to LHRH stimulation was developed upon the first challenge of LHRH. In contrast, LHRH had no effect in most preparations taken from the afternoon group rats euthanized between 1200 h and 1400 h. In the neonatal rat anterior pituitary, LHRH caused a suppression of spontaneous Ca(2+) transients. Strikingly, the second application of LHRH was capable of reproducing the suppression of Ca(2+) signals, indicating that the refractoriness to LHRH had not been established in neonatal rats. These results suggest that responsiveness to LHRH has a long-term refractoriness in adult rats, and that the physiological LHRH surge may be clocked in the morning. Moreover, LHRH-induced excitation and associated refractoriness appear to be incomplete in neonatal rats and may be acquired during development.

Na+-independent, nifedipine-resistant rat afferent arteriolar Ca2+ responses to noradrenaline

DEFF Research Database (Denmark)

Salomonsson, Max; Braunstein, Thomas Hartig; von Holstein-Rathlou, Niels-Henrik

2010-01-01

Abstract Aim: In rat afferent arterioles we investigated the role of Na(+) entry in noradrenaline (NA)-induced depolarization and voltage-dependent Ca(2+) entry together with the importance of the transient receptor potential channel (TRPC) subfamily for non-voltage-dependent Ca(2+) entry. Methods...

Chronic Stress Decreases Basal Levels of Memory-Related Signaling Molecules in Area CA1 of At-Risk (Subclinical) Model of Alzheimer's Disease.

Science.gov (United States)

Alkadhi, Karim A; Tran, Trinh T

2015-08-01

An important factor that may affect the severity and time of onset of Alzheimer's disease (AD) is chronic stress. Epidemiological studies report that chronically stressed individuals are at an increased risk for developing AD. The purpose of this study was to reveal whether chronic psychosocial stress could hasten the appearance of AD symptoms including changes in basal levels of cognition-related signaling molecules in subjects who are at risk for the disease. We investigated the effect of chronic psychosocial stress on basal levels of memory-related signaling molecules in area CA1 of subclinical rat model of AD. The subclinical symptomless rat model of AD was induced by osmotic pump continuous intracerebroventricular (ICV) infusion of 160 pmol/day Aβ1-42 for 14 days. Rats were chronically stressed using the psychosocial stress intruder model. Western blot analysis of basal protein levels of important signaling molecules in hippocampal area CA1 showed no significant difference between the subclinical AD rat model and control rat. Following six weeks of psychosocial stress, molecular analysis showed that subclinical animals subjected to stress have significantly reduced basal levels of p-CaMKII and decreased p-CaMKII/t-CaMKII ratio as well as decreased basal levels of p-CREB, total CREB, and BDNF. The present results suggest that these changes in basal levels of signaling molecules may be responsible for impaired learning, memory, and LTP in this rat model, which support the proposition that chronic stress may accelerate the emergence of AD in susceptible individuals.

Modulation of voltage-gated Ca2+ channels by G protein-coupled receptors in celiac-mesenteric ganglion neurons of septic rats.

Directory of Open Access Journals (Sweden)

Mohamed Farrag

Full Text Available Septic shock, the most severe complication associated with sepsis, is manifested by tissue hypoperfusion due, in part, to cardiovascular and autonomic dysfunction. In many cases, the splanchnic circulation becomes vasoplegic. The celiac-superior mesenteric ganglion (CSMG sympathetic neurons provide the main autonomic input to these vessels. We used the cecal ligation puncture (CLP model, which closely mimics the hemodynamic and metabolic disturbances observed in septic patients, to examine the properties and modulation of Ca2+ channels by G protein-coupled receptors in acutely dissociated rat CSMG neurons. Voltage-clamp studies 48 hr post-sepsis revealed that the Ca2+ current density in CMSG neurons from septic rats was significantly lower than those isolated from sham control rats. This reduction coincided with a significant increase in membrane surface area and a negligible increase in Ca2+ current amplitude. Possible explanations for these findings include either cell swelling or neurite outgrowth enhancement of CSMG neurons from septic rats. Additionally, a significant rightward shift of the concentration-response relationship for the norepinephrine (NE-mediated Ca2+ current inhibition was observed in CSMG neurons from septic rats. Testing for the presence of opioid receptor subtypes in CSMG neurons, showed that mu opioid receptors were present in ~70% of CSMG, while NOP opioid receptors were found in all CSMG neurons tested. The pharmacological profile for both opioid receptor subtypes was not significantly affected by sepsis. Further, the Ca2+ current modulation by propionate, an agonist for the free fatty acid receptors GPR41 and GPR43, was not altered by sepsis. Overall, our findings suggest that CSMG function is affected by sepsis via changes in cell size and α2-adrenergic receptor-mediated Ca2+ channel modulation.

Intracellular [Ca2+] and Vo2 after manipulation of the free-energy of the Na+/Ca(2+)-exchanger in isolated rat ventricular myocytes

NARCIS (Netherlands)

Fiolet, J. W.; Baartscheer, A.; Schumacher, C. A.

1995-01-01

We have investigated whether the Na+/Ca(2+)-exchanger has a functional regulatory role in the control of oxidative metabolism in suspensions of isolated rat ventricular myocytes. Therefore we simultaneously measured intracellular [Ca2+] ([Ca2+]i) with Indo-1 and respiratory rate (Vo2) after abrupt

Synbiotic loaded chitosan-Ca-alginate microparticles reduces inflammation in the TNBS model of rat colitis.

Science.gov (United States)

Ivanovska, Tanja Petreska; Mladenovska, Kristina; Zhivikj, Zoran; Pavlova, Maja Jurhar; Gjurovski, Ivica; Ristoski, Trpe; Petrushevska-Tozi, Lidija

2017-07-15

New therapeutic strategies against inflammatory bowel disease (IBD) consider the usage of probiotics, prebiotics and synbiotics as beneficial for the intestinal microbial balance. Limitations of such an approach are addressed into difference in survival, persistence, colonization and variable effects among different probiotic strains, lack in understanding of probiotic mechanisms of action, as well the complex etiology of IBD. The anti-inflammatory activity of Lactobacillus casei 01 (L. casei 01) was assessed in trinitrobenzenesulphonic (TNBS) acid model of rat colitis when the probiotic was used alone and/or in combination with oligofructose-enriched inulin (Synergy 1), and as synbiotic (L. casei 01+Synergy 1) loaded chitosan-Ca-alginate microparticles; all suspended in ayran. The results from the probiotic/synbiotic treatments (8.5-8.9log CFU g -1 L. casei 01 and 1.5% Synergy 1) have shown reduction in the colonic damage and increased lactobacilli counts in feces. Lactobacilli translocation to sterile extra-intestinal organs demonstrated acceptable safety of the probiotic strain used. The best effect at reducing inflammation and lesions associated with a significant decline in myeloperoxidase (MPO) activity was observed in rats that received synbiotic microparticles. This finding suggests colon targeted delivery of the probiotics/synbiotics, as an advantageous approach in prevention and treatment of IBD. Copyright © 2017 Elsevier B.V. All rights reserved.

Dyrk1A-ASF-CaMKIIδ Signaling Is Involved in Valsartan Inhibition of Cardiac Hypertrophy in Renovascular Hypertensive Rats.

Science.gov (United States)

Yao, Jian; Qin, Xiaotong; Zhu, Jianhua; Sheng, Hongzhuan

2016-01-01

It is known that the expression, activity and alternative splicing of Ca2+/calmodulin-dependent protein kinase IIδ (CaMKIIδ) are dysregulated in the cardiac remodeling process. Recently, we found a further signaling pathway, by which dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A) regulates the alternative splicing of CaMKIIδ via the alternative splicing factor (ASF), i.e., Dyrk1A-ASF-CaMKIIδ. In this study, we aimed to investigate whether Dyrk1A-ASF-CaMKIIδ signaling was involved in valsartan inhibition of cardiac hypertrophy in renovascular hypertensive rats. Rats were subjected to two kidney-one clip (2K1C) surgery and then treated with valsartan (30 mg/kg/day) for 8 weeks. Hypertrophic parameter analysis was then performed. Western blot analysis was used to determine the protein expression of Dyrk1A and ASF and RT-PCR was used to analyze the alternative splicing of CaMKIIδ in the left ventricular (LV) sample. Valsartan attenuated cardiac hypertrophy in 2K1C rats but without impairment of cardiac systolic function. Increased protein expression of Dyrk1A and decreased protein expression of ASF were observed in the LV sample of 2K1C rats. Treatment of 2K1C rats with valsartan reversed the changes in Dyrk1A and ASF expression in the LV sample. Valsartan adjusted the 2K1C-induced imbalance in alternative splicing of CaMKIIδ by upregulating the mRNA expression of CaMKIIδC and downregulating the mRNA expression of CaMKIIδA and CaMKIIδB. Valsartan inhibition of cardiac hypertrophy in renovascular hypertensive rats was mediated, at least partly, by Dyrk1A-ASF-CaMKIIδ signaling. © 2015 S. Karger AG, Basel.

[99mTc]Demotate 2 in the detection of sst2-positive tumours: a preclinical comparison with [111In]DOTA-tate

International Nuclear Information System (INIS)

Maina, Theodosia; Nock, Berthold A.; Cordopatis, Paul; Bernard, Bert F.; Breeman, Wout A.P.; Gameren, Arthur van; Berg, Ria van den; Krenning, Eric P.; Jong, Marion de; Reubi, Jean-Claude

2006-01-01

The aim of this study was to evaluate [ 99m Tc]Demotate 2 ([ 99m Tc-N 4 0-1 ,Asp 0 ,Tyr 3 ]octreotate) as a candidate for in vivo imaging of sst 2 -positive tumours and to compare it with [ 111 In]DOTA-tate ([ 111 In-DOTA 0 ,Tyr 3 ]octreotate). Labelling of Demotate 2 with 99m Tc was performed at room temperature using SnCl 2 as reductant in the presence of citrate at alkaline pH. Radiochemical analysis involved ITLC and HPLC methods. Peptide conjugate affinities for sst 2 were determined by receptor autoradiography on rat brain cortex sections using [DOTA 0 , 125 I-Tyr 3 ]octreotate as the radioligand. The affinity profile of Demotate 2 for human sst 1 -sst 5 was studied by receptor autoradiography in cell preparations using the universal somatostatin radioligand [ 125 I][Leu 8 ,(D)Trp 22 ,Tyr 25 ]somatostatin-28. The internalisation rates of [ 99m Tc]Demotate 2 and [ 111 In]DOTA-tate were compared in sst 2 -positive and -negative control cell lines. Biodistribution of radiopeptides was studied in male Lewis rats bearing CA20948 tumours. Peptide conjugates showed selectivity and a high affinity binding for sst 2 (Demotate 2 IC 50 =3.2 nM and DOTA-tate IC 50 =5.4 nM). [ 99m Tc]Demotate 2, like [ 111 In]DOTA-tate, internalised rapidly in all sst 2 -positive cells tested, but not in sst 2 -negative control cells. After injection in CA20948 tumour-bearing rats both radiopeptides showed high and specific uptake in the sst 2 -positive organs and in the implanted tumour and rapid excretion from non-target tissues via the kidneys. [ 99m Tc]Demotate 2, similarly to the known sst 2 -targeting agent [ 111 In]DOTA-tate, showed promising biological qualities for application in the scintigraphy of sst 2 -positive tumours. (orig.)

Early postischemic 45Ca accumulation in rat dentate hilus

International Nuclear Information System (INIS)

Benveniste, H.; Diemer, N.H.

1988-01-01

Several studies have found postischemic regional accumulation of calcium to be time-dependent and coincident with the progression of ischemic cell change. In the most vulnerable cells in the hippocampus one would therefore expect to find a primary and specific early uptake of calcium after ischemia. Autoradiograms of 45 Ca and 3 H-inulin distribution were investigated before and 1 h after 20 min ischemia in the rat hippocampus. Two different methodological approaches were used for administration of 45 Ca: (a) administration via microdialysis probes, (b) intraventricular injection. During control conditions the 45 Ca autoradiograms showed variations in distribution volume in accordance with 3 H-inulin determination of extracellular space size. One hour after ischemia a massive accumulation of 45 Ca was found in the dentate hilus. No change in the distribution pattern of 3 H-inulin could be demonstrated 1 h after ischemia. We suggest that 45 Ca accumulation in dentate hilus 1 h after ischemia is a result of increased Ca 2+ uptake before irreversible cell damage occurs and is not due to passive influx of calcium across a leaky plasma membrane

Localisation of selected Ca2+-transport systems in rat's heart and kidney and their modulation by stress

International Nuclear Information System (INIS)

Zacikova, L.

2000-01-01

This thesis deals with the identification of selected calcium transport systems and their modulation by immobilization stress in rat heart and kidney. In our experiments we used normotensive (Sprague-Dawley, Wistar-Kyoto) and hypertensive (SHR) strains. We compared mRNA levels, protein expression and activity of the Na + /Ca 2+ exchanger from hearts of control animals, animals subjected to a single (once) or repeated (seven times) immobilization stress and from animals treated continually with cortisol. We have observed that immobilization stress increased both, gene expression and protein message of the Na + /Ca 2 + exchanger in rat cardiac left, but not right ventricle. This effect is not mediated through the glucocorticoid responsive element. We have found that cortisol decreased activity of the N a +/Ca 2+ exchanger without changing expression and protein amount of this transport system. IP3 receptor of type I and 2 was detected on mRNA levels in rat cardiac atria. Very small amounts of these receptors were observed in rat cardiac ventricles. Since it was difficult to detect these amounts in ventricles, we used 'seminested' PCR to verify expression of IP 3 R1 and 2 in cardiac ventricles. The highest levels of IP 3 R1 and 2 were expressed in left atria. Immobilization stress significantly increased mRNA IP 3 R1 and 2 in rat cardiac atria. We observed both, mRNA and type 1 IP 3 receptor's protein in renal medulla, but not in renal cortex. We have found that this receptor was approximately twice as abundant in normotensive as in genetically hypertensive rat kidney. Immobilization stress significantly down-regulated IP 3 R1 in renal medulla, but not in renal cortex. To investigate the role of NAADP in signaling we measured 45 Ca 2+ release from rat cardiac microsomes. We examined concentration and time dependence of 45 Ca 2+ release from rat cardiac microsomes. All these results could contribute to the understanding of Ca 2+ modulation in cardiac and kidney under

Neomysin inhibits Ca2+-stimulated phosphatidylinositol hydrolysis and protects cultured rat cardiomyocytes from Ca2+-dependent cell injury

International Nuclear Information System (INIS)

Babson, J.R.; Dougherty, J.M.

1991-01-01

Exposure of cultured rat cardiomyocytes to ionomycin and extracellular Ca 2+ leads to a rapid, sustained increase in intracellular free Ca 2+ as monitored by Ca 2+ -dependent phosphorylase a activation and to a subsequent loss of cardiomyocyte viability as determined by lactate dehydrogenase (LDH) leakage. The intracellular free Ca 2+ increase coincided with a rapid hydrolysis of phosphatidylinositol that preceded cell death. Phosphatidylinositol hydrolysis was monitored by the release of radiolabeled phosphoinositides from cardiomyocytes prelabeled with [2- 3 H]-myo-inositol. Neomycin, a known inhibitor of phospholipase C, inhibited the phosphatidylinositol hydrolysis and markedly reduced the extent of cell injury. Inhibitors of other Ca 2+ -activated processes, including intracellular proteases and phospholipase A 2 , had no effect on ionomycin-mediated cell injury. These data suggest that ionomycin-induced Ca 2+ -dependent cell injury in cultured cardiomyocytes may be due in part to the stimulation of phosphatidylinositol hydrolysis, presumably catalyzed by a Ca 2+ -dependent phospholipase C

Influence of a chinese crude drug on Ca2+ influx and efflux in rat visceral organs:Investigation and evaluation by 45Ca

International Nuclear Information System (INIS)

Yang Yuanyou; Liu Ning; Mo Zhengji; Xie Jianping; Liao Jiali; Mo Shangwu

2006-01-01

The influences of a Chinese crude drug, Herba Epimedii (HE), on Ca 2+ influx and efflux in the isolated rat aorta and some visceral organs were evaluated by using 45 Ca as a radioactive tracer. Additionally, its protective effect on myocardial ischemia was investigated in live animals. The results indicated that HE has significant influence on Ca 2+ influx and efflux in the isolated rat aorta, heart, and kidney, in that it can markedly block 45 Ca entering into cell and can facilitate efflux of intracellular Ca 2+ . However, among the three kinds of extracts from HE, the alkali extracts have the most obvious effect on calcium channels in visceral organs. Even if the alkali extracts are diluted by water for 10 times, the material still has a rather strong inhibition effect on calcium channels. Fortunately, the three kinds of extracts have favorable protective effect on myocardial ischemia induced by drugs or by the ligation of the coronary artery. This is consistent with the results about the Ca 2+ influx and efflux obtained by isotope tracer technique, and implies that the Chinese crude drug has attractive potential for the treatment of heart, cerebrovascular and other diseases

Significance of CaV3.2 T-type Ca2+ channels for pressure- and flow-dependent vasomotor responses in rat and mouse mesenteric small arteries

DEFF Research Database (Denmark)

Jensen, Lars Jørn; Björling, K.; Hansen, Pernille B. Lærkegaard

RNA was similar in WT vs. CaV3.2-/- mice. CONCLUSION: FMVD responses appear to rely on an endothelium-dependent hyperpolarization in rat small mesenteric arteries. CaV3.2 channels are negative feedback modulators of myogenic tone in small mesenteric artery in young mice. The age-dependent decline in CaV3...... in young CaV3.2-/- mice (8-15 weeks) vs. age-matched WT mice (Pyoung WT mice, the CaV3.2 blocker NiCl2 (30 µM) significantly enhanced myogenic tone (P... was not seen (N=4). In young and old CaV3.2-/- mice no effects of NiCl2 were observed. The FMVD response in rat mesenteric arteries was not blocked by L-NAME, but was almost abolished by the SKCa/IKCa channel blockers apamin/TRAM-34 (50 nM/1 µM) (P

Quantification of the rat left ventricle force and Ca2+ -frequency relationships: similarities to dog and human.

Science.gov (United States)

Taylor, David G; Parilak, Leonard D; LeWinter, Martin M; Knot, Harm J

2004-01-01

To measure and quantify the force-frequency (FFR) and Ca(2+)-frequency (CaFR) relationships in isolated rat left ventricular (LV) muscle at physiological heart rates and compare the obtained FFR to that measured in larger mammalian muscle from dog and human using the same experimental protocol. Rat papillary muscle was isolated from the LV of adult male Sprague-Dawley rats, and dog and human muscles were from free-wall LV biopsies, loaded with the Ca(2+) indicator Fura-2, allowed to recover from isolation trauma and then subjected to direct electrical stimulation while measuring force production and intracellular Ca(2+) transients. We obtained a positive FFR between 1 and 4 Hz that is qualitatively similar to that found in isolated LV epicardial muscle strips from dogs and humans with normal LV function. The FFR reflects the cytosolic Ca(2+) transients in amplitude. Isoproterenol yielded an enhancement in force, but flattening of the FFR, whereas cyclopiazonic acid caused depression of FFR amplitude without changing frequency-dependent shape. We describe an experimental protocol that consistently yields positive FFRs in rat, dog and human LV muscle at stimulation rates between 1 and 4 Hz, without significant qualitative differences. We attribute previously observed negative FFR in rat muscle to an increase in SERCA activity early after excision and preparation of the muscle strips.

Regulation of the Na+/Ca2+ exchanger in rat pancreatic ducts

DEFF Research Database (Denmark)

Ankorina-Stark, I; Amstrup, J; Novak, I

2002-01-01

by hormones/agonists affecting pancreatic secretion. Whole pancreas, pure pancreatic acini and ducts were obtained from rats and used for RT-PCR and Western blot analysis, immunohistochemistry and intracellular Ca2+ measurements using Fura-2. RT-PCR analysis indicated Na+/Ca2+-exchanger isoforms NCX1.......3 and NCX1.7 in acini and pancreas. Western blot with NCX1 antibody identified bands of 70, 120 and 150 kDa in isolated ducts, acini and pancreas. Immunofluorescence experiments showed the Na+/Ca2+ exchanger on the basolateral membrane of acini and small intercalated/intralobular ducts, but in larger...

Regulatory effect of connexin 43 on basal Ca2+ signaling in rat ventricular myocytes.

Directory of Open Access Journals (Sweden)

Chen Li

Full Text Available BACKGROUND: It has been found that gap junction-associated intracellular Ca(2+ [Ca(2+](i disturbance contributes to the arrhythmogenesis and hyperconstriction in diseased heart. However, whether functional gaps are also involved in the regulation of normal Ca(2+ signaling, in particular the basal [Ca(2+](i activities, is unclear. METHODS AND RESULTS: Global and local Ca(2+ signaling and gap permeability were monitored in cultured neonatal rat ventricular myocytes (NRVMs and freshly isolated mouse ventricular myocytes by Fluo4/AM and Lucifer yellow (LY, respectively. The results showed that inhibition of gap communication by heptanol, Gap 27 and flufenamic acid or interference of connexin 43 (Cx43 with siRNA led to a significant suppression of LY uptake and, importantly, attenuations of global Ca(2+ transients and local Ca(2+ sparks in monolayer NRVMs and Ca(2+ sparks in adult ventricular myocytes. In contrast, overexpression of rat-Cx43 in NRVMs induced enhancements in the above measurements, and so did in HEK293 cells expressing rat Cx43. Additionally, membrane-permeable inositol 1,4,5-trisphosphate (IP(3 butyryloxymethyl ester and phenylephrine, an agonist of adrenergic receptor, could relieve the inhibited Ca(2+ signal and LY uptake by gap uncouplers, whereas blockade of IP(3 receptor with xestospongin C or 2-aminoethoxydiphenylborate mimicked the effects of gap inhibitors. More importantly, all these gap-associated effects on Ca(2+ signaling were also found in single NRVMs that only have hemichannels instead of gap junctions. Further immunostaining/immunoblotting single myocytes with antibody against Cx43 demonstrated apparent increases in membrane labeling of Cx43 and non-junctional Cx43 in overexpressed cells, suggesting functional hemichannels exist and also contribute to the Ca(2+ signaling regulation in cardiomyocytes. CONCLUSIONS: These data demonstrate that Cx43-associated gap coupling plays a role in the regulation of resting Ca(2

Changes in inhibitory CA1 network in dual pathology model of epilepsy.

Science.gov (United States)

Ouardouz, Mohamed; Carmant, Lionel

2012-01-01

The combination of two precipitating factors appears to be more and more recognized in patients with temporal lobe epilepsy. Using a two-hit rat model, with a neonatal freeze lesion mimicking a focal cortical malformation combined with hyperthermia-induced seizures mimicking febrile seizures, we have previously reported an increase of inhibition in CA1 pyramidal cells at P20. Here, we investigated the changes affecting excitatory and inhibitory drive onto CA1 interneurons to better define the changes in CA1 inhibitory networks and their paradoxical role in epileptogenesis, using electrophysiological recordings in CA1 hippocampus from rat pups (16-20 d old). We investigated interneurons in CA1 hippocampal area located in stratum oriens (Or) and at the border of strata lacunosum and moleculare (L-M). Our results revealed an increase of the excitatory drive to both types of interneurons with no change in the inhibitory drive. The mechanisms underlying the increase of excitatory synaptic currents (EPSCs) in both types of interneurons are different. In Or interneurons, the amplitude of spontaneous and miniature EPSCs increased, while their frequency was not affected suggesting changes at the post-synaptic level. In L-M interneurons, the frequency of spontaneous EPSCs increases, but the amplitude is not affected. Analyses of miniature EPSCs showed no changes in both their frequency and amplitude. We concluded that L-M interneurons increase in excitatory drive is due to a change in Shaffer collateral axon excitability. The changes described here in CA1 inhibitory network may actually contribute to the epileptogenicity observed in this dual pathology model by increasing pyramidal cell synchronization.

Aconitine-induced Ca2+ overload causes arrhythmia and triggers apoptosis through p38 MAPK signaling pathway in rats

International Nuclear Information System (INIS)

Sun, Gui-bo; Sun, Hong; Meng, Xiang-bao; Hu, Jin; Zhang, Qiang; Liu, Bo; Wang, Min; Xu, Hui-bo; Sun, Xiao-bo

2014-01-01

Aconitine is a major bioactive diterpenoid alkaloid with high content derived from herbal aconitum plants. Emerging evidence indicates that voltage-dependent Na + channels have pivotal roles in the cardiotoxicity of aconitine. However, no reports are available on the role of Ca 2+ in aconitine poisoning. In this study, we explored the importance of pathological Ca 2+ signaling in aconitine poisoning in vitro and in vivo. We found that Ca 2+ overload lead to accelerated beating rhythm in adult rat ventricular myocytes and caused arrhythmia in conscious freely moving rats. To investigate effects of aconitine on myocardial injury, we performed cytotoxicity assay in neonatal rat ventricular myocytes (NRVMs), as well as measured lactate dehydrogenase level in the culture medium of NRVMs and activities of serum cardiac enzymes in rats. The results showed that aconitine resulted in myocardial injury and reduced NRVMs viability dose-dependently. To confirm the pro-apoptotic effects, we performed flow cytometric detection, cardiac histology, transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. The results showed that aconitine stimulated apoptosis time-dependently. The expression analysis of Ca 2+ handling proteins demonstrated that aconitine promoted Ca 2+ overload through the expression regulation of Ca 2+ handling proteins. The expression analysis of apoptosis-related proteins revealed that pro-apoptotic protein expression was upregulated, and anti-apoptotic protein BCL-2 expression was downregulated. Furthermore, increased phosphorylation of MAPK family members, especially the P-P38/P38 ratio was found in cardiac tissues. Hence, our results suggest that aconitine significantly aggravates Ca 2+ overload and causes arrhythmia and finally promotes apoptotic development via phosphorylation of P38 mitogen-activated protein kinase. - Highlights: • Aconitine-induced Ca 2+ overload causes arrhythmia in rats

Effect of acetylcholine receptors on the pain-related electrical activities in the hippocampal CA3 region of morphine-addicted rats.

Science.gov (United States)

Li, Guan Zeng; Liu, Zhe Hui; Wei, XinYa; Zhao, Pan; Yang, Chun Xiao; Xu, Man Ying

2015-07-01

To determine the effect of acetylcholine (ACh), pilocarpine, and atropine on pain evoked responses of pain excited neurons (PEN) and pain inhibited neurons (PIN) in hippocampal CA3 region of morphine addicted rats. Female Wistar rats, weighing between 230-260 g were used in this study. Morphine addicted rats were generated by subcutaneous injection of increasing concentrations of morphine hydrochloride for six days. Trains of electrical impulses applied to the sciatic nerve were used as noxious stimulation and the evoked electrical activities of PEN or PIN in hippocampal CA3 area were recorded using extracellular electrophysiological recording techniques in hippocampal slices. The effect of acetylcholine receptor stimulation by ACh, the muscarinic agonist pilocarpine, and the muscarinic antagonist atropine on the pain evoked responses of pain related electrical activities was analyzed in hippocampal CA3 area of morphine addicted rats. Intra-CA3 microinjection of ACh (2 μg/1 μl) or pilocarpine (2 μg/1 μl) decreased the discharge frequency and prolonged the firing latency of PEN, but increased the discharge frequency and shortened the firing inhibitory duration (ID) of PIN. The intra-CA3 administration of atropine (0.5 μg/1 μl) produced opposite effect. The peak activity of cholinergic modulators was 2 to 4 min later in morphine addicted rats compared to peak activity previously observed in normal rats. ACh dependent modulation of noxious stimulation exists in hippocampal CA3 area of morphine addicted rats. Morphine treatment may shift the sensitivity of pain related neurons towards a delayed response to muscarinergic neurotransmission in hippocampal CA3 region.

Effect of acetylcholine receptors on the pain-related electrical activities in the hippocampal CA3 region of morphine-addicted rats

Directory of Open Access Journals (Sweden)

Guan Zeng Li

2015-07-01

Full Text Available Objective(s:To determine the effect of acetylcholine (ACh, pilocarpine, and atropine on pain evoked responses of pain excited neurons (PEN and pain inhibited neurons (PIN in hippocampal CA3 region of morphine addicted rats. Materials and Methods:Female Wistar rats, weighing between 230-260 g were used in this study. Morphine addicted rats were generated by subcutaneous injection of increasing concentrations of morphine hydrochloride for six days. Trains of electrical impulses applied to the sciatic nerve were used as noxious stimulation and the evoked electrical activities of PEN or PIN in hippocampal CA3 area were recorded using extracellular electrophysiological recording techniques in hippocampal slices. The effect of acetylcholine receptor stimulation byACh, the muscarinic agonist pilocarpine, and the muscarinic antagonist atropine on the pain evoked responses of pain related electrical activities was analyzed in hippocampal CA3 area of morphine addicted rats. Results:Intra-CA3 microinjection of ACh (2 μg/1 μl or pilocarpine (2 μg/1 μl decreased the discharge frequency and prolonged the firing latency of PEN, but increased the discharge frequency and shortened the firing inhibitory duration (ID of PIN. The intra-CA3 administration of atropine (0.5 μg/1 μl produced opposite effect. The peak activity of cholinergic modulators was 2 to 4 min later in morphine addicted rats compared to peak activity previously observed in normal rats. Conclusion: ACh dependent modulation of noxious stimulation exists in hippocampal CA3 area of morphine addicted rats. Morphine treatment may shift the sensitivity of pain related neurons towards a delayed response to muscarinergic neurotransmission in hippocampal CA3 region.

The transfer of 45Ca, 85Sr and 140Ba from mother to newborn in rats

International Nuclear Information System (INIS)

Taylor, D.M.; Bligh, P.H.

1992-01-01

Comparative studies of the transfer of 45 Ca, 85 Sr and 140 Ba from mother to offspring were made in August rats following intravenous injection of the radionuclides either during gestation or 40 to 90 days prior to mating. Immediately following parturition, and before suckling could begin, the newborn rats were removed from the dam and killed. For each radionuclide the percentage of the initial maternal activity transferred to individual offspring decreased exponentially with time between injection and parturition with a mean half-time of 3.1 ± 0.7 (SD) days. Transfer ratios measured in rats injected either during or prior to gestation were similar and could be described by the rounded values Ca: Sr: Ba = 1.00: 0.4:0.2. Placental transfer ratios were not significantly different from those for gastrointestinal absorption of the three radionuclides, plus 226 Ra, in adult rats of the same strain. For humans transfer ratios from mother to baby of Ca: Sr: Ba: Ra = 1.0: 0.6: 0.4: 0.4 are suggested. (author)

Aconitine-induced Ca{sup 2+} overload causes arrhythmia and triggers apoptosis through p38 MAPK signaling pathway in rats

Energy Technology Data Exchange (ETDEWEB)

Sun, Gui-bo; Sun, Hong; Meng, Xiang-bao [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193 (China); Hu, Jin; Zhang, Qiang; Liu, Bo [Academy of Chinese Medical Sciences of Jilin Province, Changchun, Jilin 130021 (China); Wang, Min [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193 (China); Xu, Hui-bo, E-mail: xhb_6505@163.com [Academy of Chinese Medical Sciences of Jilin Province, Changchun, Jilin 130021 (China); Sun, Xiao-bo, E-mail: sun_xiaobo163@163.com [Key Laboratory of Bioactive Substances and Resources Utilization of Chinese Herbal Medicine, Ministry of Education, Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100193 (China)

2014-08-15

Aconitine is a major bioactive diterpenoid alkaloid with high content derived from herbal aconitum plants. Emerging evidence indicates that voltage-dependent Na{sup +} channels have pivotal roles in the cardiotoxicity of aconitine. However, no reports are available on the role of Ca{sup 2+} in aconitine poisoning. In this study, we explored the importance of pathological Ca{sup 2+} signaling in aconitine poisoning in vitro and in vivo. We found that Ca{sup 2+} overload lead to accelerated beating rhythm in adult rat ventricular myocytes and caused arrhythmia in conscious freely moving rats. To investigate effects of aconitine on myocardial injury, we performed cytotoxicity assay in neonatal rat ventricular myocytes (NRVMs), as well as measured lactate dehydrogenase level in the culture medium of NRVMs and activities of serum cardiac enzymes in rats. The results showed that aconitine resulted in myocardial injury and reduced NRVMs viability dose-dependently. To confirm the pro-apoptotic effects, we performed flow cytometric detection, cardiac histology, transmission electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. The results showed that aconitine stimulated apoptosis time-dependently. The expression analysis of Ca{sup 2+} handling proteins demonstrated that aconitine promoted Ca{sup 2+} overload through the expression regulation of Ca{sup 2+} handling proteins. The expression analysis of apoptosis-related proteins revealed that pro-apoptotic protein expression was upregulated, and anti-apoptotic protein BCL-2 expression was downregulated. Furthermore, increased phosphorylation of MAPK family members, especially the P-P38/P38 ratio was found in cardiac tissues. Hence, our results suggest that aconitine significantly aggravates Ca{sup 2+} overload and causes arrhythmia and finally promotes apoptotic development via phosphorylation of P38 mitogen-activated protein kinase. - Highlights: • Aconitine-induced Ca

Rat vas deferens SERCA2 is modulated by Ca2+/calmodulin protein kinase II-mediated phosphorylation

International Nuclear Information System (INIS)

Rodriguez, J.B.R.; Muzi-Filho, H.; Valverde, R.H.F.; Quintas, L.E.M.; Noel, F.; Einicker-Lamas, M.; Cunha, V.M.N.

2013-01-01

Ca 2+ pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca 2+ -ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca 2+ -ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (∼115 kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca 2+ (Ca 0.5 = 780 nM) and a low sensitivity to vanadate (IC 50 = 41 µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca 2+ /calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca 2+ and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca 2+ accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca 2+ and CaM, possibly via CaMKII, in a process that results in stimulation of Ca 2+ pumping activity

Teratogenic effect of calcium edetate (CaEDTA) in rats and the protective effect of zinc.

Science.gov (United States)

Brownie, C F; Brownie, C; Noden, D; Krook, L; Haluska, M; Aronson, A L

1986-03-15

The calcium chelate of EDTA (CaEDTA) currently is the drug of choice in the treatment of lead intoxication. This study investigated the teratogenic potential of CaEDTA, administered parenterally during periods of organogenesis and determined if incorporating zinc into EDTA would protect against teratogenic effects. Four doses (2, 4, 6, and 8 mmol/m2/day) of CaEDTA, two concentrations (8 and 20 mmol/m2/day) of ZnEDTA and ZnCaEDTA (molar ratio 0.5:0.5:1) were used, and a saline control (0.9% NaCl). Timed-pregnant Long-Evans rats were assigned at random to the treatment groups, 20 per dose for each chelate and 30 to the saline control. Rats were injected with the chelate or saline solution sc, twice daily during the 11th through 15th days of gestation. Pups removed by cesarean section on the 21st day were processed for osseous and visceral examination. Additional animals per treatment group were used for maternal plasma and liver and fetal zinc determinations. Results showed increases in several abnormalities (submucous cleft, cleft palate, adactyly-syndactyly, curly tail, abnormal rib and vertebrae) with increasing amounts of CaEDTA. No malformations were seen with ZnEDTA at either dose or with ZnCaEDTA at 8 mmol/m2/day. However, submucous cleft was seen in 6 of 20 litters from the dams receiving the higher dose of ZnCaEDTA. It was concluded that CaEDTA is teratogenic in rats at concentrations which, except for decreased weight gain, produce no discernible toxicity to the dam, and which are comparable to the recommended therapeutic dosage in humans (1500 mg/m2/day corresponding to 4 mmol/m2/day). Protection is afforded by incorporating zinc in the chelate.

[Effect of Scalp-acupuncture Stimulation on Neurological Function and Expression of ASIC 1 a and ASIC 2 b of Hippocampal CA 1 Region in Cerebral Ischemia Rats].

Science.gov (United States)

Tian, Liang; Wang, Jin-Hai; Zhao, Min; Bao, Ying-Cun; Shang, Jun-Fang; Yan, Qi; Zhang, Zhen-Chang; Du, Xiao-Zheng; Jiang, Hua; Sun, Run-Jie; Yuan, Bo; Zhang, Xing-Hua; Zhang, Ting-Zhuo; Li, Xing-Lan

2016-10-25

To observe the influence of scalp-acupuncture on the expression of acid-sensing ion channels (ASICs) 1 a and 2 b of hippocampal CA 1 region in cerebral ischemia (CI) rats, so as to investigate its mechanism underlying improvement of ischemic stroke. Thirty-two male SD rats were randomly allocated to normal control, model, scalp-acupuncture and Amiloride group ( n =8 in each group). The model of focal CI was established by middle cerebral artery occlusion (MCAO). Scalp acupuncture stimulation was applied to bilateral Dingnieqianxiexian (MS 6) and Dingniehouxiexian (MS 7), once daily for 7 days. Rats of the Amiloride group were fed with Amiloride solution, twice a day for 7 days, and those of the normal control and model groups were grabbled and fixed in the same way with the acupuncture and Amiloride groups. The neurological deficit score was given according to Longa's method. The expression of hippocampal ASIC 1 a and ASIC 2 b was detected by immunohistochemistry, and the Ca 2+ concentration in the hippocampal tissue assayed using flowing cytometry. After the intervention, the neurological deficit score of both the scalp-acupuncture and Amiloride groups were significantly decreased in comparison with pre-treatment ( P ASIC 1 a and ASIC 2 b in the hippocampal CA 1 region and hip-pocampal Ca 2+ concentration were significantly up-regulated in the model group compared with the normal control group ( P ASIC 1 a and ASIC 2 b expression and Ca 2+ concentration ( P >0.05). Scalp-acupuncture stimulation can improve neurological function in CI rats, which may be related to its effects in suppressing the increased expression of hippocampal ASIC 1 a and ASIC 2 b proteins and in reducing calcium overload in hip-pocampal neurocytes.

Phosphorylation of CaMKII in the rat dorsal raphe nucleus plays an important role in sleep-wake regulation.

Science.gov (United States)

Cui, Su-Ying; Li, Sheng-Jie; Cui, Xiang-Yu; Zhang, Xue-Qiong; Yu, Bin; Sheng, Zhao-Fu; Huang, Yuan-Li; Cao, Qing; Xu, Ya-Ping; Lin, Zhi-Ge; Yang, Guang; Song, Jin-Zhi; Ding, Hui; Wang, Zi-Jun; Zhang, Yong-He

2016-02-01

The Ca(2+) modulation in the dorsal raphe nucleus (DRN) plays an important role in sleep-wake regulation. Calmodulin-dependent kinase II (CaMKII) is an important signal-transducing molecule that is activated by Ca(2+) . This study investigated the effects of intracellular Ca(2+) /CaMKII signaling in the DRN on sleep-wake states in rats. Maximum and minimum CaMKII phosphorylation was detected at Zeitgeber time 21 (ZT 21; wakefulness state) and ZT 3 (sleep state), respectively, across the light-dark rhythm in the DRN in rats. Six-hour sleep deprivation significantly reduced CaMKII phosphorylation in the DRN. Microinjection of the CAMKII activation inhibitor KN-93 (5 or 10 nmol) into the DRN suppressed wakefulness and enhanced rapid-eye-movement sleep (REMS) and non-REM sleep (NREMS). Application of a high dose of KN-93 (10 nmol) increased slow-wave sleep (SWS) time, SWS bouts, the mean duration of SWS, the percentage of SWS relative to total sleep, and delta power density during NREMS. Microinjection of CaCl2 (50 nmol) in the DRN increased CaMKII phosphorylation and decreased NREMS, SWS, and REMS. KN-93 abolished the inhibitory effects of CaCl2 on NREMS, SWS, and REMS. These data indicate a novel wake-promoting and sleep-suppressing role for the Ca(2+) /CaMKII signaling pathway in DRN neurons. We propose that the intracellular Ca(2+) /CaMKII signaling in the dorsal raphe nucleus (DRN) plays wake-promoting and sleep-suppressing role in rats. Intra-DRN application of KN-93 (CaMKII activation inhibitor) suppressed wakefulness and enhanced rapid-eye-movement sleep (REMS) and non-REMS (NREMS). Intra-DRN application of CaCl2 attenuated REMS and NREMS. We think these findings should provide a novel cellular and molecular mechanism of sleep-wake regulation. © 2015 International Society for Neurochemistry.

Rosiglitazone attenuates inflammation and CA3 neuronal loss following traumatic brain injury in rats

International Nuclear Information System (INIS)

Liu, Hao; Rose, Marie E.; Culver, Sherman; Ma, Xiecheng; Dixon, C. Edward; Graham, Steven H.

2016-01-01

Rosiglitazone, a potent peroxisome proliferator-activated receptor (PPAR)-γ agonist, has been shown to confer neuroprotective effects in stroke and spinal cord injury, but its role in the traumatic brain injury (TBI) is still controversial. Using a controlled cortical impact model in rats, the current study was designed to determine the effects of rosiglitazone treatment (6 mg/kg at 5 min, 6 h and 24 h post injury) upon inflammation and histological outcome at 21 d after TBI. In addition, the effects of rosiglitazone upon inflammatory cytokine transcription, vestibulomotor behavior and spatial memory function were determined at earlier time points (24 h, 1–5 d, 14–20 d post injury, respectively). Compared with the vehicle-treated group, rosiglitazone treatment suppressed production of TNFα at 24 h after TBI, attenuated activation of microglia/macrophages and increased survival of CA3 neurons but had no effect on lesion volume at 21 d after TBI. Rosiglitazone-treated animals had improved performance on beam balance testing, but there was no difference in spatial memory function as determined by Morris water maze. In summary, this study indicates that rosiglitazone treatment in the first 24 h after TBI has limited anti-inflammatory and neuroprotective effects in rat traumatic injury. Further study using an alternative dosage paradigm and more sensitive behavioral testing may be warranted. - Highlights: • Effects of rosiglitazone after CCI were evaluated using a rat TBI model. • Rosiglitazone suppressed production of TNFα at 24 h after CCI. • Rosiglitazone inhibited microglial activation at 21 d after CCI. • Rosiglitazone increased survival of CA3 neurons at 21 d after CCI. • Rosiglitazone-treated animals had improved performance in beam balance testing.

Rosiglitazone attenuates inflammation and CA3 neuronal loss following traumatic brain injury in rats

Energy Technology Data Exchange (ETDEWEB)

Liu, Hao; Rose, Marie E. [Geriatric Research Educational and Clinical Center, V.A. Pittsburgh Healthcare System, PA (United States); Department of Neurology, University of Pittsburgh School of Medicine, PA (United States); Culver, Sherman; Ma, Xiecheng; Dixon, C. Edward [Geriatric Research Educational and Clinical Center, V.A. Pittsburgh Healthcare System, PA (United States); Department of Neurosurgery, University of Pittsburgh, PA 15216 (United States); Department of Critical Care Medicine, University of Pittsburgh, PA 15216 (United States); Graham, Steven H., E-mail: Steven.Graham@va.gov [Geriatric Research Educational and Clinical Center, V.A. Pittsburgh Healthcare System, PA (United States); Department of Neurology, University of Pittsburgh School of Medicine, PA (United States)

2016-04-15

Rosiglitazone, a potent peroxisome proliferator-activated receptor (PPAR)-γ agonist, has been shown to confer neuroprotective effects in stroke and spinal cord injury, but its role in the traumatic brain injury (TBI) is still controversial. Using a controlled cortical impact model in rats, the current study was designed to determine the effects of rosiglitazone treatment (6 mg/kg at 5 min, 6 h and 24 h post injury) upon inflammation and histological outcome at 21 d after TBI. In addition, the effects of rosiglitazone upon inflammatory cytokine transcription, vestibulomotor behavior and spatial memory function were determined at earlier time points (24 h, 1–5 d, 14–20 d post injury, respectively). Compared with the vehicle-treated group, rosiglitazone treatment suppressed production of TNFα at 24 h after TBI, attenuated activation of microglia/macrophages and increased survival of CA3 neurons but had no effect on lesion volume at 21 d after TBI. Rosiglitazone-treated animals had improved performance on beam balance testing, but there was no difference in spatial memory function as determined by Morris water maze. In summary, this study indicates that rosiglitazone treatment in the first 24 h after TBI has limited anti-inflammatory and neuroprotective effects in rat traumatic injury. Further study using an alternative dosage paradigm and more sensitive behavioral testing may be warranted. - Highlights: • Effects of rosiglitazone after CCI were evaluated using a rat TBI model. • Rosiglitazone suppressed production of TNFα at 24 h after CCI. • Rosiglitazone inhibited microglial activation at 21 d after CCI. • Rosiglitazone increased survival of CA3 neurons at 21 d after CCI. • Rosiglitazone-treated animals had improved performance in beam balance testing.

Rat vas deferens SERCA2 is modulated by Ca{sup 2+}/calmodulin protein kinase II-mediated phosphorylation

Energy Technology Data Exchange (ETDEWEB)

Rodriguez, J.B.R.; Muzi-Filho, H. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Valverde, R.H.F. [Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Quintas, L.E.M. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Noel, F. [Programa de Desenvolvimento de Fármacos, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Einicker-Lamas, M. [Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil); Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagem, Rio de Janeiro, RJ (Brazil); Cunha, V.M.N. [Programa de Farmacologia e Inflamação, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ (Brazil)

2013-03-19

Ca{sup 2+} pumps are important players in smooth muscle contraction. Nevertheless, little information is available about these pumps in the vas deferens. We have determined which subtype of sarco(endo)plasmic reticulum Ca{sup 2+}-ATPase isoform (SERCA) is expressed in rat vas deferens (RVD) and its modulation by calmodulin (CaM)-dependent mechanisms. The thapsigargin-sensitive Ca{sup 2+}-ATPase from a membrane fraction containing the highest SERCA levels in the RVD homogenate has the same molecular mass (∼115 kDa) as that of SERCA2 from the rat cerebellum. It has a very high affinity for Ca{sup 2+} (Ca{sub 0.5} = 780 nM) and a low sensitivity to vanadate (IC{sub 50} = 41 µM). These facts indicate that SERCA2 is present in the RVD. Immunoblotting for CaM and Ca{sup 2+}/calmodulin-dependent protein kinase II (CaMKII) showed the expression of these two regulatory proteins. Ca{sup 2+} and CaM increased serine-phosphorylated residues of the 115-kDa protein, indicating the involvement of CaMKII in the regulatory phosphorylation of SERCA2. Phosphorylation is accompanied by an 8-fold increase of thapsigargin-sensitive Ca{sup 2+} accumulation in the lumen of vesicles derived from these membranes. These data establish that SERCA2 in the RVD is modulated by Ca{sup 2+} and CaM, possibly via CaMKII, in a process that results in stimulation of Ca{sup 2+} pumping activity.

Neuropeptide Y and nestin expression in the hippocampal CA3 region following restrained and inverted stress in rats

Institute of Scientific and Technical Information of China (English)

Guogang Sun; Ailing Li; Bo Chen; Guangbi Fan; Hongwen Xiao; Yue Chen; Jie Xu; Ye Nie; Bing Zhang; Lin Gong

2011-01-01

Our preliminary study demonstrated that neuropeptide Y (NPY)/nestin-positive cells exhibit a consistent spatial distribution in the hippocampus of normal adult rats. However, following severe acute and chronic stress-induced impaired learning and memory, synchronous decreased expression of nestin and NPY takes place in the hippocampus, and the underlying mechanisms remain unclear. In the present study, acute and chronic stress rat models were established using combined restrained and inverted stress. Results showed that learning and memory significantly decreased in acute and chronic stress rats. In addition, hippocampal cells were damaged, in particular in the acute stress rats, and nestin and NPY expression, as well as the number of NPY/nestin-positive cells in the CA3 region, significantly decreased. Furthermore, mature neurofilament 200-positive neurons were absent in the chronic stress rats. The NPY and cytoskeletal protein system equally contributed to stress-induced early learning and memory deficits, as well as sustained cerebral injury in the adult hippocampus.

Effects of aqueous extract of Hibiscus sabdariffa on renal Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in Wistar rats.

Science.gov (United States)

Olatunji, Lawrence A; Usman, Taofeek O; Adebayo, Joseph O; Olatunji, Victoria A

2012-09-01

To investigate the effects of oral administration of aqueous extract of Hibiscus sabdariffa on renal Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in rats. The 25 and 50 mg/(kg·d) of aqueous extracts of H. sabdariffa were respectively given to rats in the experimental groups for 28 d, and rats in the control group received an appropriate volume of distilled water as vehicle. Na(+)-K(+)-ATPase and Ca(2+)-Mg(2+)-ATPase activities in the kidney were assayed by spectrophotometric method. Administrations of 25 and 50 mg/(kg·d) of aqueous extract of H. sabdariffa significantly decreased the Ca(2+)-Mg(2+)-ATPase activity in the kidney of rats (Psabdariffa may preserve the renal function despite a decreased renal Ca(2+)-Mg(2+)-ATPase activity.

Nandrolone decanoate treatment affects sarcoplasmic reticulum Ca(2+) ATPase function in skinned rat slow- and fast-twitch fibres.

Science.gov (United States)

Bouhlel, Aicha; Joumaa, Wissam H; Léoty, Claude

2003-09-01

The effects of anabolic-androgenic steroid administration on the function of the sarcoplasmic reticulum (SR) pump were investigated in chemically skinned fibres from the extensor digitorum longus (EDL) and soleus muscles of sedentary rats. Twenty male rats were divided into two groups, one group received an intramuscular injection of nandrolone decanoate (15 mg x kg(-1)) weekly for 8 weeks, the second received similar weekly doses of vehicle (sterile peanut oil). Compared with control muscles, nandrolone decanoate treatment reduced SR Ca(2+) loading in EDL and soleus fibres by 49% and 29%, respectively. In control and treated muscles, the rate of Ca(2+) leakage depended on the quantity of Ca(2+) loaded. Furthermore, for similar SR Ca(2+) contents, the Ca(2+) leakage rate was not significantly modified by nandrolone decanoate treatment. Nandrolone decanoate treatment thus affects Ca (2+) uptake by the SR in a fibre-type dependent manner.

Activity-dependent intracellular Ca2+ transients in unmyelinated nerve fibres of the isolated adult rat vagus nerve.

Science.gov (United States)

Wächtler, J; Mayer, C; Grafe, P

1998-04-01

Confocal laser scanning microscopy was used to follow changes in the free intracellular calcium concentration ([Ca2+]i) in nerve fibres and adjacent Schwann cells in isolated rat vagus nerves. [Ca2+]i was monitored by the Ca2+-sensitive fluorescent dyes Calcium Green-1 and Fura Red. Intracellular Ca2+ transients were observed during repetitive (1-50 Hz) supramaximal electrical stimulation or by bath application of ATP. Trains of action potentials were more effective at elongated, fibre-like structures of the vagus nerves, whereas ATP-induced Ca2+ transients were found predominantly in regions of Schwann cell bodies. Activity-induced Ca2+ signals were unaffected by pharmacological manipulation of intracellular Ca2+ stores, during long-lasting application of purinergic receptor agonists, or by substitution of extracellular Na+ with Li+. However, they were abolished in the presence of Ca2+-free bathing solution or after the blocking of Ca2+ channels with Cd2+. Ca2+ transients were also observed during Ca2+ action potentials. Such "Ca2+ spikes" were elicited by electrical stimulation in the presence of a combination of tetrodotoxin and K+ channel blockers. These data suggest that voltage-dependent Ca2+ channels, activated during short trains of Na+ action potentials, produce an increase in intra-axonal [Ca2+] of rat vagus nerves. We did not find evidence for activity-dependent Ca2+ transients in the Schwann cells surrounding the unmyelinated axons.

Release of Zn from maternal tissues in pregnant rats deficient in Zn or Zn and Ca

International Nuclear Information System (INIS)

Hurley, L.S.; Masters, D.G.; Lonnerdal, B.; Keen, C.L.

1986-01-01

Earlier studies have shown that diets that increase tissue catabolism reduce the teratogenic effects of Zn deficiency. The hypothesis that Zn may be released from body tissues when the metabolic state is altered was further tested. Nonpregnant Sprague Dawley females were injected with Zn-65; after equilibration, the two major pools of Zn, bone and muscle, had different specific activities (SA), muscle being much higher. Females were mated and fed diets adequate in Zn and Ca (C) or deficient in Zn (ZnD) or deficient in both Zn and Ca (ZnCaD). Calculations using weight loss in ZnD and ZnCaD rats, Zn content of maternal bone and muscle, and total fetal Zn at term indicated that in ZnCaD rats a relatively small amount of Zn from bone early in pregnancy was sufficient to prevent abnormal organogenesis, but most fetal Zn came from breakdown of maternal muscle in the last 3 days of pregnancy. Isotope data supported this conclusion. SA of Zn in ZnD fetuses was equal and high, indicating that most Zn came from the same maternal tissue. High muscle SA prior to mating, and increased SA in tibia and liver during pregnancy suggest that muscle provided Zn for other maternal tissues as well as fetuses. In contrast, SA in C fetuses was less than 30% of that of the D groups, consistent with the earlier hypothesis that most fetal Zn in C rats is accrued directly from the diet

Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

International Nuclear Information System (INIS)

Padilla, J.; López, R.M.; López, P.; Castillo, M.C.; Querejeta, E.; Ruiz, A.; Castillo, E.F.

2014-01-01

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT 2 R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT 2 R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca 2+ -free medium or the subsequent tonic constrictions induced by the addition of Ca 2+ in the absence of agonists. Thus, the contractions induced by Ca 2+ release from intracellular stores and Ca 2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca 2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca 2+ . Neither levels of angiotensins nor of AT 2 R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca 2+ entry

INFLUENCE OF ELECTROACUPUNCTURE ON THE ULTRASTRUCTURE OF CA3 REGION OF THE HIPPOCAMPUS IN VD RATS

Institute of Scientific and Technical Information of China (English)

YAN Bing; XU Neng-gui; HE Li-lei; TANG Chun-zhi; SHAO Ying

2006-01-01

Objective: To observe the effect of electroacupuncture (EA) on learning and memory abilities and ultrastructure of synapses in CA3 region of the hippocampus in vascular dementia (VD) rats. Methods: A total of 32 SD rats were randomized into control (sham-operation, n = 7), model (n = 7), EA (n = 9) and medication (n=9) groups. VD model was established by occlusion of the bilateral vertebral arteries (electrocoagulation) and bilateral common carotid arteries (occlusion for 5 min and reperfusion for 10 min, repeated the procedure for 3 times to induce global ischemia). EA (150 Hz, 1 mA) was applied to "Baihui"(百会GV 20), "Geshu"(膈俞 BL 17), "Pishu"(脾俞 BL 20) and "Shenshu"(肾俞 BL 23) for 20 min, once daily and continuously for 15 days. In medication group, the rats were fed with Nimotong (12 mg/kg), once daily and continuously for 15 days. Morris water maze method was used to test the animals' learning and memory abilities (latencies to find the hidden platform determined by place navigation trials, and latencies to cross on the location of the removed platform determined by spatial probe trials) after the treatment. Ultrastructural changes (numerical density, NA,surface density, Sv and volume density, Vv) of Gray type 1 synapses in CA3 region of the hippocampus were observed by using transmission electronic microscope and automatic image analysis system. Results: 1 ) Place navigation test showed that in comparison with control group, the average escape latency of VD group was significantly longer (P＜0.01), while in comparison with VD group, the latencies of both EA and medication groups decreased significantly ( P＜0.01 ). No significant difference was found between EA and medication groups in the escape latency (P＞0.05). 2) Spatial probe-test displayed that in comparison with control group, the times which the animals crossed the target platform in VD group decreased significantly (P＜0.01), while compared with VD group, those of both EA and

Attenuation of Ca2+ homeostasis, oxidative stress, and mitochondrial dysfunctions in diabetic rat heart: insulin therapy or aerobic exercise?

Science.gov (United States)

da Silva, Márcia F; Natali, Antônio J; da Silva, Edson; Gomes, Gilton J; Teodoro, Bruno G; Cunha, Daise N Q; Drummond, Lucas R; Drummond, Filipe R; Moura, Anselmo G; Belfort, Felipe G; de Oliveira, Alessandro; Maldonado, Izabel R S C; Alberici, Luciane C

2015-07-15

We tested the effects of swimming training and insulin therapy, either alone or in combination, on the intracellular calcium ([Ca(2+)]i) homeostasis, oxidative stress, and mitochondrial functions in diabetic rat hearts. Male Wistar rats were separated into control, diabetic, or diabetic plus insulin groups. Type 1 diabetes mellitus was induced by streptozotocin (STZ). Insulin-treated groups received 1 to 4 UI of insulin daily for 8 wk. Each group was divided into sedentary or exercised rats. Trained groups were submitted to swimming (90 min/day, 5 days/wk, 8 wk). [Ca(2+)]i transient in left ventricular myocytes (LVM), oxidative stress in LV tissue, and mitochondrial functions in the heart were assessed. Diabetes reduced the amplitude and prolonged the times to peak and to half decay of the [Ca(2+)]i transient in LVM, increased NADPH oxidase-4 (Nox-4) expression, decreased superoxide dismutase (SOD), and increased carbonyl protein contents in LV tissue. In isolated mitochondria, diabetes increased Ca(2+) uptake, susceptibility to permeability transition pore (MPTP) opening, uncoupling protein-2 (UCP-2) expression, and oxygen consumption but reduced H2O2 release. Swimming training corrected the time course of the [Ca(2+)]i transient, UCP-2 expression, and mitochondrial Ca(2+) uptake. Insulin replacement further normalized [Ca(2+)]i transient amplitude, Nox-4 expression, and carbonyl content. Alongside these benefits, the combination of both therapies restored the LV tissue SOD and mitochondrial O2 consumption, H2O2 release, and MPTP opening. In conclusion, the combination of swimming training with insulin replacement was more effective in attenuating intracellular Ca(2+) disruptions, oxidative stress, and mitochondrial dysfunctions in STZ-induced diabetic rat hearts. Copyright © 2015 the American Physiological Society.

Effect of excess dietary salt on calcium metabolism and bone mineral in a spaceflight rat model

Science.gov (United States)

Navidi, Meena; Wolinsky, Ira; Fung, Paul; Arnaud, Sara B.

1995-01-01

High levels of salt promote urinary calcium (UCa) loss and have the potential to cause bone mineral deficits if intestinal Ca absorption does not compensate for these losses. To determine the effect of excess dietary salt on the osteopenia that follows skeletal unloading, we used a spaceflight model that unloads the hindlimbs of 200-g rats by tail suspension (S). Rats were studied for 2 wk on diets containing high salt (4 and 8%) and normal calcium (0.45%) and for 4 wk on diets containing 8% salt (HiNa) and 0.2% Ca (LoCa). Final body weights were 9-11% lower in S than in control rats (C) in both experiments, reflecting lower growth rates in S than in C during pair feeding. UCa represented 12% of dietary Ca on HiNA diets and was twofold higher in S than in C transiently during unloading. Net intestinal Ca absorption was consistently 11-18% lower in S than in C. Serum 1,25-dihydroxyvitamin D was unaffected by either LoCa or HiNa diets in S but was increased by LoCa and HiNa diets in C. Despite depressed intestinal Ca absoption in S and a sluggish response of the Ca endocrine system to HiNa diets, UCa loss did not appear to affect the osteopenia induced by unloading. Although any deficit in bone mineral content from HiNa diets may have been too small to detect or the duration of the study too short to manifest, there were clear differences in Ca metabolism from control levels in the response of the spaceflight model to HiNa diets, indicated by depression of intestinal Ca absorption and its regulatory hormone.

Effects of Shuyusan on monoamine neurotransmitters expression in a rat model of chronic stress-induced depression

Institute of Scientific and Technical Information of China (English)

Yuanyuan Zhang; Jianjun Jia; Liping Chen; Zhitao Han; Yulan Zhao; Honghong Zhang; Yazhuo Hu

2011-01-01

Shuyusan, a traditional Chinese medicine, was shown to improve depression symptoms and behavioral scores, as well as increase 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid, and 5-hydroxytryptophan levels, in a rat model of chronic stress-induced depression. However, dopamine, noradrenalin, and 3-methoxy-4-hydroxyphenylglycol expressions remained unchanged following Shuyusan treatment. Compared with the model group, the number of 5-HT-positive neurons in layers 4-5 of the frontal cortex, as well as hippocampal CA1 and CA3 regions, significantly increased following Shuyusan treatment. These results suggested that Shuyusan improved symptoms in a rat model of chronic stress-induced depression with mechanisms that involved 5-HT, 5-HT metabolite, 5-HT precursor expressions.

Lateralized hippocampal effects of vasoactive intestinal peptide on learning and memory in rats in a model of depression.

Science.gov (United States)

Ivanova, Margarita; Belcheva, Stiliana; Belcheva, Iren; Negrev, Negrin; Tashev, Roman

2012-06-01

Findings of pharmacological studies revealed that vasoactive intestinal peptide (VIP) plays a modulatory role in learning and memory. A role of the peptide in the neurobiological mechanisms of affective disorders was also suggested. The objectives are to study the involvement of VIP in learning and memory processes after unilateral and bilateral local application into hippocampal CA1 area in rats with a model of depression (bilateral olfactory bulbectomy--OBX) and to test whether VIP receptors could affect cognition. VIP (50 ng) and combination (VIP(6-28) 10 ng + VIP 50 ng) microinjected bilaterally or into the right CA1 area improved the learning and memory of OBX rats in shuttle-box and step-through behavioral tests as compared to the saline-treated OBX controls. Left-side VIP microinjections did not affect the number of avoidances (shuttle box) and learning criteria (step through) as compared to the left-side saline-treated OBX controls. The administration of the combination into left CA1 influenced positively the performance in the step-through task. VIP antagonist (VIP(6-28), 10 ng) did not affect learning and memory of OBX rats. These findings suggest asymmetric effect of VIP on cognitive processes in hippocampus of rats with OBX model of depression. Our results point to a lateralized modulatory effect of VIP injected in the hippocampal CA1 area on the avoidance deficits in OBX rats. The right CA1 area was predominantly involved in the positive effect of VIP on learning and memory. A possible role of the PAC1 receptors is suggested.

Distribution of voltage-dependent and intracellular Ca2+ channels in submucosal neurons from rat distal colon.

Science.gov (United States)

Rehn, Matthias; Bader, Sandra; Bell, Anna; Diener, Martin

2013-09-01

We recently observed a bradykinin-induced increase in the cytosolic Ca2+ concentration in submucosal neurons of rat colon, an increase inhibited by blockers of voltage-dependent Ca2+ (Ca(v)) channels. As the types of Ca(v) channels used by this part of the enteric nervous system are unknown, the expression of various Ca(v) subunits has been investigated in whole-mount submucosal preparations by immunohistochemistry. Submucosal neurons, identified by a neuronal marker (microtubule-associated protein 2), are immunoreactive for Ca(v)1.2, Ca(v)1.3 and Ca(v)2.2, expression being confirmed by reverse transcription plus the polymerase chain reaction. These data agree with previous observations that the inhibition of L- and N-type Ca2+ currents strongly inhibits the response to bradykinin. However, whole-cell patch-clamp experiments have revealed that bradykinin does not enhance Ca2+ inward currents under voltage-clamp conditions. Consequently, bradykinin does not directly interact with Ca(v) channels. Instead, the kinin-induced Ca2+ influx is caused indirectly by the membrane depolarization evoked by this peptide. As intracellular Ca2+ channels on Ca(2+)-storing organelles can also contribute to Ca2+ signaling, their expression has been investigated by imaging experiments and immunohistochemistry. Inositol 1,4,5-trisphosphate (IP3) receptors (IP3R) have been functionally demonstrated in submucosal neurons loaded with the Ca(2+)-sensitive fluorescent dye, fura-2. Histamine, a typical agonist coupled to the phospholipase C pathway, induces an increase in the fura-2 signal ratio, which is suppressed by 2-aminophenylborate, a blocker of IP3 receptors. The expression of IP3R1 has been confirmed by immunohistochemistry. In contrast, ryanodine, tested over a wide concentration range, evokes no increase in the cytosolic Ca2+ concentration nor is there immunohistochemical evidence for the expression of ryanodine receptors in these neurons. Thus, rat submucosal neurons are equipped

[Effect of electromagnetic radiation on discharge activity of neurons in the hippocampus CA1 in rats].

Science.gov (United States)

Tong, Jun; Chen, Su; Liu, Xiang-Ming; Hao, Dong-Mei

2013-09-01

In order to explore effect of electromagnetic radiation on learning and memory ability of hippocampus neuron in rats, the changes in discharge patterns and overall electrical activity of hippocampus neuron after electromagnetic radiation were observed. Rat neurons discharge was recorded with glass electrode extracellular recording technology and a polygraph respectively. Radiation frequency of electromagnetic wave was 900 MHZ and the power was 10 W/m2. In glass electrode extracellular recording, the rats were separately irradiated for 10, 20, 30, 40, 50 and 60 min, every points repeated 10 times and updated interval of 1h, observing the changes in neuron discharge and spontaneous discharge patterns after electromagnetic radiation. In polygraph recording experiments, irradiation group rats for five days a week, 6 hours per day, repeatedly for 10 weeks, memory electrical changes in control group and irradiation group rats when they were feeding were repeatedly monitored by the implanted electrodes, observing the changes in peak electric digits and the largest amplitude in hippocampal CA1 area, and taking some electromagnetic radiation sampling sequence for correlation analysis. (1) Electromagnetic radiation had an inhibitory role on discharge frequency of the hippocampus CA1 region neurons. After electromagnetic radiation, discharge frequency of the hippocampus CA1 region neurons was reduced, but the changes in scale was not obvious. (2) Electromagnetic radiation might change the spontaneous discharge patterns of hippocampus CA1 region neurons, which made the explosive discharge pattern increased obviously. (3) Peak potential total number within 5 min in irradiation group was significantly reduced, the largest amplitude was less than that of control group. (4) Using mathematical method to make the correlation analysis of the electromagnetic radiation sampling sequence, that of irradiation group was less than that of control group, indicating that there was a tending

Intrathecal infusion of a Ca(2+)-permeable AMPA channel blocker slows loss of both motor neurons and of the astrocyte glutamate transporter, GLT-1 in a mutant SOD1 rat model of ALS.

Science.gov (United States)

Yin, Hong Z; Tang, Darryl T; Weiss, John H

2007-10-01

Elevated extracellular glutamate, resulting from a loss of astrocytic glutamate transport capacity, may contribute to excitotoxic motor neuron (MN) damage in ALS. Accounting for their high excitotoxic vulnerability, MNs possess large numbers of unusual Ca(2+)-permeable AMPA channels (Ca-AMPA channels), the activation of which triggers mitochondrial Ca(2+) overload and strong reactive oxygen species (ROS) generation. However, the causes of the astrocytic glutamate transport loss remain unexplained. To assess the role of Ca-AMPA channels on the evolution of pathology in vivo, we have examined effects of prolonged intrathecal infusion of the Ca-AMPA channel blocker, 1-naphthyl acetylspermine (NAS), in G93A transgenic rat models of ALS. In wild-type animals, immunoreactivity for the astrocytic glutamate transporter, GLT-1, was particularly strong around ventral horn MNs. However, a marked loss of ventral horn GLT-1 was observed, along with substantial MN damage, prior to onset of symptoms (90-100 days) in the G93A rats. Conversely, labeling with the oxidative marker, nitrotyrosine, was increased in the neuropil surrounding MNs in the transgenic animals. Compared to sham-treated G93A animals, 30-day NAS infusions (starting at 67+/-2 days of age) markedly diminished the loss of both MNs and of astrocytic GLT-1 labeling. These observations are compatible with the hypothesis that activation of Ca-AMPA channels on MNs contributes, likely in part through oxidative mechanisms, to loss of glutamate transporter in surrounding astrocytes.

Ca uptake and its influence by growth hormone in osteoblasts of fetal rat calvaria

International Nuclear Information System (INIS)

Wang Hongfu; Jin Weifang; Sekimoto Haku

1994-01-01

Uptake and release of Ca 2+ are important functions of osteoblasts. In the paper we studied the uptake of calcium and influence by Growth Hormone in osteoblasts of fetal rat calvaria by liquid scintillation spectrometry of 45 Ca 2+ . In short-term cultures of the bone derived cells, the uptake of 45 Ca 2+ increased steadily. The activity of 45 Ca 2+ in the cells of 15 minute cultures was 2∼3 times of that in the 0 minute cultures. It continued to increase in the cells of 30 minute cultures. Exposure of the bone cells to GH at 55.3 ng/ml increased the uptake of 45 Ca 2+ by 2.3 times in the 30 minute cultures and 1.5 times in the 60 minute cultures than those of the control

Ca2+ uptake and cellular integrity in rat EDL muscle exposed to electrostimulation, electroporation, or A23187

DEFF Research Database (Denmark)

Gissel, Hanne; Clausen, Torben

2003-01-01

We tested the hypothesis that increased Ca2+ uptake in rat extensor digitorum longus (EDL) muscle elicits cell membrane damage as assessed from release of the intracellular enzyme lactate dehydrogenase (LDH). This was done by using 1) electrostimulation, 2) electroporation, and 3) the Ca2+ ionoph...

Two organizational effects of pubertal testosterone in male rats: transient social memory and a shift away from long-term potentiation following a tetanus in hippocampal CA1.

Science.gov (United States)

Hebbard, Pamela C; King, Rebecca R; Malsbury, Charles W; Harley, Carolyn W

2003-08-01

The organizational role of pubertal androgen receptor (AR) activation in synaptic plasticity in hippocampal CA1 and in social memory was assessed. Earlier data suggest pubertal testosterone reduces adult hippocampal synaptic plasticity. Four groups were created following gonadectomy at the onset of puberty: rats given testosterone; rats given testosterone but with the AR antagonist flutamide, present during puberty; rats given testosterone at the end of puberty; and rats given cholesterol at the end of puberty. A tetanus normally inducing long-term potentiation (LTP) was used to stimulate CA1 in the urethane-anesthetized adults during the dark phase of their cycle. Social memory was assessed prior to electrophysiology. Social memory for a juvenile rat at 120 min was seen only in rats not exposed to AR activation during puberty. Pubertal AR activation may induce the reduced social memory of male rats. Early CA1 LTP occurred following tetanus in rats with no pubertal testosterone. Short-term potentiation occurred in rats exposed to pubertal testosterone. Unexpectedly, rats with pubertal AR activation developed long-term depression (LTD). The same pattern was seen in normal male rats. Lack of LTP during the dark phase is consistent with other data on circadian modulation of CA1 LTP. No correlations were seen among social memory scores and CA1 plasticity measures. These data argue for two organizational effects of pubertal testosterone: (1) CA1 synaptic plasticity shifts away from potentiation toward depression; (2) social memory is reduced. Enduring effects of pubertal androgen on limbic circuits may contribute to reorganized behaviors in the postpubertal period.

Modeling CICR in rat ventricular myocytes: voltage clamp studies

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Palade Philip T

2010-11-01

Full Text Available Abstract Background The past thirty-five years have seen an intense search for the molecular mechanisms underlying calcium-induced calcium-release (CICR in cardiac myocytes, with voltage clamp (VC studies being the leading tool employed. Several VC protocols including lowering of extracellular calcium to affect Ca2+ loading of the sarcoplasmic reticulum (SR, and administration of blockers caffeine and thapsigargin have been utilized to probe the phenomena surrounding SR Ca2+ release. Here, we develop a deterministic mathematical model of a rat ventricular myocyte under VC conditions, to better understand mechanisms underlying the response of an isolated cell to calcium perturbation. Motivation for the study was to pinpoint key control variables influencing CICR and examine the role of CICR in the context of a physiological control system regulating cytosolic Ca2+ concentration ([Ca2+]myo. Methods The cell model consists of an electrical-equivalent model for the cell membrane and a fluid-compartment model describing the flux of ionic species between the extracellular and several intracellular compartments (cell cytosol, SR and the dyadic coupling unit (DCU, in which resides the mechanistic basis of CICR. The DCU is described as a controller-actuator mechanism, internally stabilized by negative feedback control of the unit's two diametrically-opposed Ca2+ channels (trigger-channel and release-channel. It releases Ca2+ flux into the cyto-plasm and is in turn enclosed within a negative feedback loop involving the SERCA pump, regulating[Ca2+]myo. Results Our model reproduces measured VC data published by several laboratories, and generates graded Ca2+ release at high Ca2+ gain in a homeostatically-controlled environment where [Ca2+]myo is precisely regulated. We elucidate the importance of the DCU elements in this process, particularly the role of the ryanodine receptor in controlling SR Ca2+ release, its activation by trigger Ca2+, and its

Ca2+ signaling in injured in situ endothelium of rat aorta.

Science.gov (United States)

Berra-Romani, Roberto; Raqeeb, Abdul; Avelino-Cruz, José Everardo; Moccia, Francesco; Oldani, Amanda; Speroni, Francisco; Taglietti, Vanni; Tanzi, Franco

2008-09-01

The inner wall of excised rat aorta was scraped by a microelectrode and Ca2+ signals were investigated by fluorescence microscopy in endothelial cells (ECs) directly coupled with injured cells. The injury caused an immediate increase in the intracellular Ca2+ concentration ([Ca2+]i), followed by a long-lasting decay phase due to Ca2+ influx from extracellular space. The immediate response was mainly due to activation of purinergic receptors, as shown by the effect of P2X and P2Y receptors agonists and antagonists, such as suramin, alpha,beta-MeATP, MRS-2179 and 2-MeSAMP. Inhibition of store-operated Ca2+ influx did not affect either the peak response or the decay phase. Furthermore, the latter was: (i) insensitive to phospholipase C inhibition, (ii) sensitive to the gap junction blockers, palmitoleic acid, heptanol, octanol and oleamide, and (iii) sensitive to La3+ and Ni2+, but not to Gd3+. Finally, ethidium bromide or Lucifer Yellow did not enter ECs facing the scraped area. These results suggest that endothelium scraping: (i) causes a short-lasting stimulation of healthy ECs by extracellular nucleotides released from damaged cells and (ii) uncouples the hemichannels of the ECs facing the injury site; these hemichannels do not fully close and allow a long-lasting Ca2+ entry.

Effects of thyroid hormones on calcium contents and 45Ca exchange in rat skeletal muscle

International Nuclear Information System (INIS)

Everts, M.E.; Clausen, T.

1986-01-01

In 4-wk-old rats, pretreatment with L-triiodothyronine (T3) increased calcium content by 100% and the 30-min 45 Ca uptake by 64% in the soleus, whereas the extensor digitorum longus (EDL) muscle showed no significant change. The stimulation of 45 Ca uptake was resistant to dantrolene and methoxyverapamil (D600) and could not be attributed to altered permeability of the plasma membrane to calcium, but appears to reflect increased net accumulation of calcium in intracellular pools. The stimulating effect of high K0 (20 mM) on 45 Ca uptake was more pronounced in soleus than in EDL and could be suppressed by dantrolene and D600. The results indicate that the effects of T3 on calcium content and 45 Ca exchange are primarily exerted on muscles containing a large proportion of slow-twitch, oxidative fibers. In soleus muscle from hyperthyroid rats the stimulating effects of high K0 on 45 Ca uptake and lactate production were, respectively, 3.4 and 4.5 times larger than in those obtained from controls. These observations further support the earlier proposed idea [C. van Hardeveld and T. Clausen. Am. J. Physiol. 247 (Endocrinol. Metab. 10): E421-E430, 1984] that the metabolic effects of thyroid hormone depend on the availability of cellular as well as extracellular calcium

Effects of thyroid hormones on calcium contents and 45Ca exchange in rat skeletal muscle

Energy Technology Data Exchange (ETDEWEB)

Everts, M.E.; Clausen, T.

1986-09-01

In 4-wk-old rats, pretreatment with L-triiodothyronine (T3) increased calcium content by 100% and the 30-min /sup 45/Ca uptake by 64% in the soleus, whereas the extensor digitorum longus (EDL) muscle showed no significant change. The stimulation of /sup 45/Ca uptake was resistant to dantrolene and methoxyverapamil (D600) and could not be attributed to altered permeability of the plasma membrane to calcium, but appears to reflect increased net accumulation of calcium in intracellular pools. The stimulating effect of high K0 (20 mM) on /sup 45/Ca uptake was more pronounced in soleus than in EDL and could be suppressed by dantrolene and D600. The results indicate that the effects of T3 on calcium content and /sup 45/Ca exchange are primarily exerted on muscles containing a large proportion of slow-twitch, oxidative fibers. In soleus muscle from hyperthyroid rats the stimulating effects of high K0 on /sup 45/Ca uptake and lactate production were, respectively, 3.4 and 4.5 times larger than in those obtained from controls. These observations further support the earlier proposed idea (C. van Hardeveld and T. Clausen. Am. J. Physiol. 247 (Endocrinol. Metab. 10): E421-E430, 1984) that the metabolic effects of thyroid hormone depend on the availability of cellular as well as extracellular calcium.

Ca2+ cycling in heart cells from ground squirrels: adaptive strategies for intracellular Ca2+ homeostasis.

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Xiao-Chen Li

Full Text Available Heart tissues from hibernating mammals, such as ground squirrels, are able to endure hypothermia, hypoxia and other extreme insulting factors that are fatal for human and nonhibernating mammals. This study was designed to understand adaptive mechanisms involved in intracellular Ca(2+ homeostasis in cardiomyocytes from the mammalian hibernator, ground squirrel, compared to rat. Electrophysiological and confocal imaging experiments showed that the voltage-dependence of L-type Ca(2+ current (I(Ca was shifted to higher potentials in ventricular myocytes from ground squirrels vs. rats. The elevated threshold of I(Ca did not compromise the Ca(2+-induced Ca(2+ release, because a higher depolarization rate and a longer duration of action potential compensated the voltage shift of I(Ca. Both the caffeine-sensitive and caffeine-resistant components of cytosolic Ca(2+ removal were more rapid in ground squirrels. Ca(2+ sparks in ground squirrels exhibited larger amplitude/size and much lower frequency than in rats. Due to the high I(Ca threshold, low SR Ca(2+ leak and rapid cytosolic Ca(2+ clearance, heart cells from ground squirrels exhibited better capability in maintaining intracellular Ca(2+ homeostasis than those from rats and other nonhibernating mammals. These findings not only reveal adaptive mechanisms of hibernation, but also provide novel strategies against Ca(2+ overload-related heart diseases.

Effect of exercise training on Ca2+ release units of left ventricular myocytes of spontaneously hypertensive rats.

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Carneiro-Júnior, M A; Quintão-Júnior, J F; Drummond, L R; Lavorato, V N; Drummond, F R; Amadeu, M A; Oliveira, E M; Felix, L B; Cruz, J S; Mill, J G; Natali, A J; Prímola-Gomes, T N

2014-08-29

In cardiomyocytes, calcium (Ca2+) release units comprise clusters of intracellular Ca2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F0), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes.

Effect of exercise training on Ca2+ release units of left ventricular myocytes of spontaneously hypertensive rats

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M.A. Carneiro-Júnior

2014-11-01

Full Text Available In cardiomyocytes, calcium (Ca2+ release units comprise clusters of intracellular Ca2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age were divided into 4 groups: normotensive (NC and hypertensive control (HC, and normotensive (NT and hypertensive trained (HT animals (7 rats per group. NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2 and FK506 binding protein (FKBP12.6 increased (270% and decreased (88%, respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230% and normalizing FKBP12.6 gene expression (112%. Hypertension also increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F0, full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm, total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms, time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms, and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms. These changes were partially reversed in HT rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms. Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes.

Effect of exercise training on Ca2+ release units of left ventricular myocytes of spontaneously hypertensive rats

International Nuclear Information System (INIS)

Carneiro-Júnior, M.A.; Quintão-Júnior, J.F.; Drummond, L.R.; Lavorato, V.N.; Drummond, F.R.; Amadeu, M.A.; Oliveira, E.M.; Felix, L.B.; Cruz, J.S.; Mill, J.G.; Natali, A.J.; Prímola-Gomes, T.N.

2014-01-01

In cardiomyocytes, calcium (Ca 2+ ) release units comprise clusters of intracellular Ca 2+ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca 2+ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca 2+ sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F 0 ), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca 2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F 0 , full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of left ventricular myocytes

Inhibition of PKC-dependent extracellular Ca{sup 2+} entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas

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Padilla, J.; López, R.M.; López, P.; Castillo, M.C.; Querejeta, E.; Ruiz, A.; Castillo, E.F. [Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, México, DF (Mexico)

2014-08-01

We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT{sub 2}R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT{sub 2}R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca{sup 2+}-free medium or the subsequent tonic constrictions induced by the addition of Ca{sup 2+} in the absence of agonists. Thus, the contractions induced by Ca{sup 2+} release from intracellular stores and Ca{sup 2+} influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca{sup 2+} channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca{sup 2+}. Neither levels of angiotensins nor of AT{sub 2}R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca{sup 2+} entry.

Effects of the hexahydroxyhexane myoinositol on bone uptake of radiocalcium in rats: Effect of inositol and vitamin D2 on bone uptake of 45Ca in rats

International Nuclear Information System (INIS)

Angeloff, L.G.; Skoryna, S.C.; Henderson, I.W.D.

1977-01-01

The objective of this study was to investigate the effects of inositol and vitamin D 2 on bone uptake of 45 Ca in rats. The radioactive calcium was administered to young rats by orogastric intubation (2 μci/100 g body weight (b.wt.)) with inositol (20 mg/100 g b.wt) and/or vitamin D 2 (500 IU/100g b.wt) to normal rats. Bone uptake of 45 Ca was measured after 24 hours by standard technique. Inositol alone produced a 48% increase in calcium uptake. It is concluded that inositol significantly increases bone uptake to radioactive calcium (P>0.005). Simultaneous administration of vitamin D 2 decreases the effect of inositol considerably, while vitamin D 2 has no significant effect. (author)

Modified cytoplasmic Ca2+ sequestration contributes to spinal cord injury-induced augmentation of nerve-evoked contractions in the rat tail artery.

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Hussain Al Dera

Full Text Available In rat tail artery (RTA, spinal cord injury (SCI increases nerve-evoked contractions and the contribution of L-type Ca2+ channels to these responses. In RTAs from unoperated rats, these channels play a minor role in contractions and Bay K8644 (L-type channel agonist mimics the effects of SCI. Here we investigated the mechanisms underlying the facilitatory actions of SCI and Bay K8644 on nerve-evoked contractions of RTAs and the hypothesis that Ca2+ entering via L-type Ca2+ channels is rapidly sequestered by the sarcoplasmic reticulum (SR limiting its role in contraction. In situ electrochemical detection of noradrenaline was used to assess if Bay K8644 increased noradrenaline release. Perforated patch recordings were used to assess if SCI changed the Ca2+ current recorded in RTA myocytes. Wire myography was used to assess if SCI modified the effects of Bay K8644 and of interrupting SR Ca2+ uptake on nerve-evoked contractions. Bay K8644 did not change noradrenaline-induced oxidation currents. Neither the size nor gating of Ca2+ currents differed between myocytes from sham-operated (control and SCI rats. Bay K8644 increased nerve-evoked contractions in RTAs from both control and SCI rats, but the magnitude of this effect was reduced by SCI. By contrast, depleting SR Ca2+ stores with ryanodine or cyclopiazonic acid selectively increased nerve-evoked contractions in control RTAs. Cyclopiazonic acid also selectively increased the blockade of these responses by nifedipine (L-type channel blocker in control RTAs, whereas ryanodine increased the blockade produced by nifedipine in both groups of RTAs. These findings suggest that Ca2+ entering via L-type channels is normally rapidly sequestered limiting its access to the contractile mechanism. Furthermore, the findings suggest SCI reduces the role of this mechanism.

Heart failure-induced changes of voltage-gated Ca2+ channels and cell excitability in rat cardiac postganglionic neurons.

Science.gov (United States)

Tu, Huiyin; Liu, Jinxu; Zhang, Dongze; Zheng, Hong; Patel, Kaushik P; Cornish, Kurtis G; Wang, Wei-Zhong; Muelleman, Robert L; Li, Yu-Long

2014-01-15

Chronic heart failure (CHF) is characterized by decreased cardiac parasympathetic and increased cardiac sympathetic nerve activity. This autonomic imbalance increases the risk of arrhythmias and sudden death in patients with CHF. We hypothesized that the molecular and cellular alterations of cardiac postganglionic parasympathetic (CPP) neurons located in the intracardiac ganglia and sympathetic (CPS) neurons located in the stellate ganglia (SG) possibly link to the cardiac autonomic imbalance in CHF. Rat CHF was induced by left coronary artery ligation. Single-cell real-time PCR and immunofluorescent data showed that L (Ca(v)1.2 and Ca(v)1.3), P/Q (Ca(v)2.1), N (Ca(v)2.2), and R (Ca(v)2.3) types of Ca2+ channels were expressed in CPP and CPS neurons, but CHF decreased the mRNA and protein expression of only the N-type Ca2+ channels in CPP neurons, and it did not affect mRNA and protein expression of all Ca2+ channel subtypes in the CPS neurons. Patch-clamp recording confirmed that CHF reduced N-type Ca2+ currents and cell excitability in the CPP neurons and enhanced N-type Ca2+ currents and cell excitability in the CPS neurons. N-type Ca2+ channel blocker (1 μM ω-conotoxin GVIA) lowered Ca2+ currents and cell excitability in the CPP and CPS neurons from sham-operated and CHF rats. These results suggest that CHF reduces the N-type Ca2+ channel currents and cell excitability in the CPP neurons and enhances the N-type Ca2+ currents and cell excitability in the CPS neurons, which may contribute to the cardiac autonomic imbalance in CHF.

Estradiol receptors mediate estradiol-induced inhibition of mitochondrial Ca^{2+} efflux in rat caudate nucleus and brain stem

OpenAIRE

PETROVIC, SNJEZANA; MILOSEVIC, MAJA; RISTIC-MEDIC, DANIJELA; VELICKOVIC, NATASA; DRAKULIC, DUNJA; GRKOVIC, IVANA; HORVAT, ANICA

2015-01-01

Our earlier studies found that in vitro estradiol modulates mitochondrial Ca2+ transport in discrete brain regions. The present study examined the role of estradiol receptors (ERs) in estradiol-induced inhibition of Ca^{2+} efflux from synaptosomal mitochondria isolated from rat caudate nuclei and brain stems. Radioactively labeled CaCl_2 (0.6?0.75 µCi ^45CaCl_{2}) was used for Ca^{2+} transport monitoring. The results revealed that in the presence of ER antagonist 7\\alpha,17ß-[9[(4,4,5,5,5-...

Neuroprotective effects of oleuropein against cognitive dysfunction induced by colchicine in hippocampal CA1 area in rats.

Science.gov (United States)

Pourkhodadad, Soheila; Alirezaei, Masoud; Moghaddasi, Mehrnoush; Ahmadvand, Hassan; Karami, Manizheh; Delfan, Bahram; Khanipour, Zahra

2016-09-01

Alzheimer's disease is a progressive neurodegenerative disorder with decline in memory. The role of oxidative stress is well known in the pathogenesis of the disease. The purpose of this study was to evaluate pretreatment effects of oleuropein on oxidative status and cognitive dysfunction induced by colchicine in the hippocampal CA1 area. Male Wistar rats were pretreated orally once daily for 10 days with oleuropein at doses of 10, 15 and 20 mg/kg. Thereafter, colchicine (15 μg/rat) was administered into the CA1 area of the hippocampus to induce cognitive dysfunction. The Morris water maze was used to assess learning and memory. Biochemical parameters such as glutathione peroxidase and catalase activities, nitric oxide and malondialdehyde concentrations were measured to evaluate the antioxidant status in the rat hippocampus. Our results indicated that colchicine significantly impaired spatial memory and induced oxidative stress; in contrast, oleuropein pretreatment significantly improved learning and memory retention, and attenuated the oxidative damage. The results clearly indicate that oleuropein has neuroprotective effects against colchicine-induced cognitive dysfunction and oxidative damage in rats.

Rock Tea extract (Jasonia glutinosa) relaxes rat aortic smooth muscle by inhibition of L-type Ca(2+) channels.

Science.gov (United States)

Valero, Marta Sofía; Oliván-Viguera, Aida; Garrido, Irene; Langa, Elisa; Berzosa, César; López, Víctor; Gómez-Rincón, Carlota; Murillo, María Divina; Köhler, Ralf

2015-12-01

In traditional herbal medicine, Rock Tea (Jasonia glutinosa) is known for its prophylactic and therapeutic value in various disorders including arterial hypertension. However, the mechanism by which Rock Tea exerts blood pressure-lowering actions has not been elucidated yet. Our aim was to demonstrate vasorelaxing effects of Rock Tea extract and to reveal its possible action mechanism. Isometric myography was conducted on high-K+-precontracted rings from rat thoracic aorta and tested extracts at concentrations of 0.5-5 mg/ml. Whole-cell patch-clamp experiments were performed in rat aortic vascular smooth muscle cells (line A7r5) to determine blocking effects on L-type Ca(2+) channels. Rock Tea extract relaxed the aorta contracted by high [K+] concentration dependently with an EC50 of ≈2.4 mg/ml and produced ≈75 % relaxation at the highest concentration tested. The L-type Ca(2+) channel blocker, verapamil (10(-6) M), had similar effects. Rock Tea extract had no effect in nominally Ca(2+)-free high-K(+) buffer but significantly inhibited contractions to re-addition of Ca(2+). Rock Tea extract inhibited the contractions induced by the L-type Ca(2+) channel activator Bay K 8644 (10(-5) M) and by phenylephrine (10(-6) M). Rock Tea extract and Y-27632 (10(-6) M), Rho-kinase inhibitor, had similar effects and the respective effects were not additive. Patch-clamp experiments demonstrated that Rock Tea extract (2.5 mg/ml) virtually abolished L-type Ca(2+) currents in A7r5. We conclude that Rock Tea extract produced vasorelaxation of rat aorta and that this relaxant effect is mediated by inhibition of L-type Ca(2+) channels. Rock Tea extracts may be of phytomedicinal value for prevention and adjuvant treatment of hypertension and other cardiovascular diseases.

Electrolytic lesions of dorsal CA3 impair episodic-like memory in rats.

Science.gov (United States)

Li, Jay-Shake; Chao, Yuen-Shin

2008-02-01

Episodic memory is the ability to recollect one's past experiences occurring in an unique spatial and temporal context. In non-human animals, it is expressed in the ability to combine "what", "where" and "when" factors to form an integrated memory system. During the search for its neural substrates, the hippocampus has attracted a lot of attentions. Yet, it is not yet possible to induce a pure episodic-like memory deficit in animal studies without being confounded by impairments in the spatial cognition. Here, we present a lesion study evidencing direct links between the hippocampus CA3 region and the episodic-like memory in rats. In a spontaneous object exploration task, lesioned rats showed no interaction between the temporal and spatial elements in their memory associated with the objects. In separate tests carried out subsequently, the same animals still expressed abilities to process spatial, temporal, and object recognition memory. In conclusions, our results support the idea that the hippocampus CA3 has a particular status in the neural mechanism of the episodic-like memory system. It is responsible for combining information from different modules of cognitive processes.

Safety of the Transcranial Focal Electrical Stimulation via Tripolar Concentric Ring Electrodes for Hippocampal CA3 Subregion Neurons in Rats.

Science.gov (United States)

Mucio-Ramírez, Samuel; Makeyev, Oleksandr

2017-01-01

Epilepsy is a neurological disorder that affects approximately one percent of the world population. Noninvasive electrical brain stimulation via tripolar concentric ring electrodes has been proposed as an alternative/complementary therapy for seizure control. Previous results suggest its efficacy attenuating acute seizures in penicillin, pilocarpine-induced status epilepticus, and pentylenetetrazole-induced rat seizure models and its safety for the rat scalp, cortical integrity, and memory formation. In this study, neuronal counting was used to assess possible tissue damage in rats ( n = 36) due to the single dose or five doses (given every 24 hours) of stimulation on hippocampal CA3 subregion neurons 24 hours, one week, and one month after the last stimulation dose. Full factorial analysis of variance showed no statistically significant difference in the number of neurons between control and stimulation-treated animals ( p  = 0.71). Moreover, it showed no statistically significant differences due to the number of stimulation doses ( p  = 0.71) nor due to the delay after the last stimulation dose ( p  = 0.96). Obtained results suggest that stimulation at current parameters (50 mA, 200  μ s, 300 Hz, biphasic, charge-balanced pulses for 2 minutes) does not induce neuronal damage in the hippocampal CA3 subregion of the brain.

Safety of the Transcranial Focal Electrical Stimulation via Tripolar Concentric Ring Electrodes for Hippocampal CA3 Subregion Neurons in Rats

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Samuel Mucio-Ramírez

2017-01-01

Full Text Available Epilepsy is a neurological disorder that affects approximately one percent of the world population. Noninvasive electrical brain stimulation via tripolar concentric ring electrodes has been proposed as an alternative/complementary therapy for seizure control. Previous results suggest its efficacy attenuating acute seizures in penicillin, pilocarpine-induced status epilepticus, and pentylenetetrazole-induced rat seizure models and its safety for the rat scalp, cortical integrity, and memory formation. In this study, neuronal counting was used to assess possible tissue damage in rats (n=36 due to the single dose or five doses (given every 24 hours of stimulation on hippocampal CA3 subregion neurons 24 hours, one week, and one month after the last stimulation dose. Full factorial analysis of variance showed no statistically significant difference in the number of neurons between control and stimulation-treated animals (p = 0.71. Moreover, it showed no statistically significant differences due to the number of stimulation doses (p = 0.71 nor due to the delay after the last stimulation dose (p = 0.96. Obtained results suggest that stimulation at current parameters (50 mA, 200 μs, 300 Hz, biphasic, charge-balanced pulses for 2 minutes does not induce neuronal damage in the hippocampal CA3 subregion of the brain.

Different expressions of high voltage-activated Ca2+ channel types in the rostral reticular thalamic nucleus of the absence epileptic WAG/Rij rat.

NARCIS (Netherlands)

Bovenkamp-Janssen, M.C. van de; Scheenen, W.J.J.M.; Kuijpers-Kwant, F.J.; Kozicz, L.T.; Veening, J.G.; Luijtelaar, E.L.J.M. van; McEnery, M.W.; Roubos, E.W.

2004-01-01

In the WAG/Rij rat, a model for human absence epilepsy, spike-wave discharges (SWD) and absence epileptic behavior develop after the age of 3 months. The rostral part of the reticular thalamic nucleus (rRTN) is involved in SWD. Ca(2+) channels play a central role in the initiation and maintenance of

Single-prolonged stress induces endoplasmic reticulum-dependent apoptosis in the hippocampus in a rat model of post-traumatic stress disorder.

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Fang Han

Full Text Available BACKGROUND: Our previous research indicated that apoptosis induced atrophy in the hippocampus of post-traumatic stress disorder (PTSD rats. Endoplasmic reticulum (ER stress-induced apoptosis has been implicated in the development of several disorder diseases. The aim of this study was to investigate whether endoplasmic reticulum-related pathway is involved in single-prolonged stress (SPS induces apoptosis in the hippocampus of PTSD rats by examining the expression levels of three important indicators in the ER-related apoptotic pathway: Glucose-regulated protein (GRP 78, caspase-12 and Ca(2+/CaM/CaMkinaseIIα (CaMkIIα. METHODS: Wistar rats were sacrificed at 1, 4 and 7 days after SPS. SPS is a reliable animal model of PTSD. The apoptotic cells in the hippocampus were assessed by TUNEL method and transmission electron microscopy (TEM. Free intracellular Ca(2+ concentration was measured. GRP78 expression was examined by immunohistochemistry, western blotting and RT-PCR. mRNA of caspase-12 and CaM/CaMkIIα were determined by RT-PCR. RESULTS: Our results showed that apoptotic cells were increased in the SPS rats. TEM analysis revealed characteristic morphological changes of apoptosis in these cells. We observed that GRP78 was significantly up-regulated during early PTSD, and then recovered at 7 days after SPS. By RT-PCR, we observed that the change in caspase-12 expression level was similar to that in GRP78. Moreover, the free intracellular Ca(2+ concentration was significantly higher at 1 day after SPS and decreased in 7 days. CaM expression increased significantly, while CaMKIIα expression decreased significantly in the hippocampus at 1 day after SPS. CONCLUSION: SPS induced change in the expression levels of GRP78, caspase-12 and Ca(2+/CaM/CaMkIIα in the hippocampus of PTSD rats indicated that the endoplasmic reticulum pathway may be involved in PTSD-induced apoptosis.

Oxidative stress evoked damages leading to attenuated memory and inhibition of NMDAR–CaMKII–ERK/CREB signalling on consumption of aspartame in rat model

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Ashok Iyaswamy

2018-04-01

Full Text Available Many controversial reports are available on the use of aspartame as it releases methanol as one of its metabolite during metabolism. The present study proposes to investigate whether long term (90 days aspartame (40 mg/kg b.wt administration could induce oxidative stress and alter the memory in Wistar strain male albino rats. To mimic the human methanol metabolism, methotrexate (MTX-treated rats were included as a model to study the effects of aspartame. Wistar strain albino rats were administered with aspartame (40 mg/kg b.wt orally and studied along with controls and MTX-treated controls. Aspartame interfered in the body weight and corticosterone levels in the rats. A marked increase in the mRNA and protein expression of neuronal nitric oxide synthase (nNOS and induced nitric oxide synthase (iNOS which resulted in the increased nitric oxide radical's level indicating that aspartame is a stressor. These reactive nitrogen species could be responsible for the altered cell membrane integrity and even cause death of neurons by necrosis or apoptosis. The animals showed a marked decrease in learning, spatial working and spatial recognition memory deficit in the Morris water maze and Y-maze performance task which could have resulted due to reduced hippocampal acetylcholine esterase (AChE activity. The animal brain homogenate also revealed the decrease in the phosphorylation of NMDAR1–CaMKII–ERK/CREB signalling pathway, which well documents the inhibition of phosphorylation leads to the excitotoxicity of the neurons and memory decline. This effect may be due to methanol which may also activate the NOS levels, microglia and astrocytes, inducing neurodegeneration in brain. Neuronal shrinkage of hippocampal layer due to degeneration of pyramidal cells revealed the abnormal neuronal morphology of pyramidal cell layers in the aspartame treated animals. These findings demonstrate that aspartame metabolites could be a contributing factor for the

Effect of exercise training on Ca{sup 2+} release units of left ventricular myocytes of spontaneously hypertensive rats

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Carneiro-Júnior, M.A. [Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, ES (Brazil); Universidade Federal de Viçosa, Laboratório de Biologia do Exercício, Departamento de Educação Física, Viçosa, MG (Brazil); Quintão-Júnior, J.F.; Drummond, L.R.; Lavorato, V.N.; Drummond, F.R. [Universidade Federal de Viçosa, Laboratório de Biologia do Exercício, Departamento de Educação Física, Viçosa, MG (Brazil); Amadeu, M.A.; Oliveira, E.M. [Universidade de São Paulo, Laboratório de Bioquímica e Biologia Molecular do Exercício, Escola de Educação Física e Esportes, São Paulo, SP (Brazil); Felix, L.B. [Universidade Federal de Viçosa, Departamento de Engenharia Elétrica, Viçosa, MG (Brazil); Cruz, J.S. [Universidade Federal de Minas Gerais, Laboratório de Membranas Excitáveis e Biologia Cardiovascular, Departamento de Bioquímica e Imunologia, Belo Horizonte, MG (Brazil); Mill, J.G. [Universidade Federal do Espírito Santo, Departamento de Ciências Fisiológicas, Vitória, ES (Brazil); Natali, A.J.; Prímola-Gomes, T.N. [Universidade Federal de Viçosa, Laboratório de Biologia do Exercício, Departamento de Educação Física, Viçosa, MG (Brazil)

2014-08-29

In cardiomyocytes, calcium (Ca{sup 2+}) release units comprise clusters of intracellular Ca{sup 2+} release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca{sup 2+} sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca{sup 2+} sparks (HC=7.61±0.26 vs NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08 vs NC=0.324±0.10 ΔF/F{sub 0}), full width at half-maximum amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration (HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06 vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12 vs NC=10.21±0.22 ms). These changes were partially reversed in HT rats (frequency of Ca{sup 2+} sparks=6.26±0.19 µm/s, amplitude=0.282±0.10 ΔF/F{sub 0}, full width at half-maximum amplitude=1.14±0.01 µm, total duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release units of

CaV3.1 isoform of T-type calcium channels supports excitability of rat and mouse ventral tegmental area neurons.

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Tracy, Matthew E; Tesic, Vesna; Stamenic, Tamara Timic; Joksimovic, Srdjan M; Busquet, Nicolas; Jevtovic-Todorovic, Vesna; Todorovic, Slobodan M

2018-03-23

Recent data have implicated voltage-gated calcium channels in the regulation of the excitability of neurons within the mesolimbic reward system. While the attention of most research has centered on high voltage L-type calcium channel activity, the presence and role of the low voltage-gated T-type calcium channel (T-channels) has not been well explored. Hence, we investigated T-channel properties in the neurons of the ventral tegmental area (VTA) utilizing wild-type (WT) rats and mice, Ca V 3.1 knock-out (KO) mice, and TH-eGFP knock-in (KI) rats in acute horizontal brain slices of adolescent animals. In voltage-clamp experiments, we first assessed T-channel activity in WT rats with characteristic properties of voltage-dependent activation and inactivation, as well as characteristic crisscrossing patterns of macroscopic current kinetics. T-current kinetics were similar in WT mice and WT rats but T-currents were abolished in Ca V 3.1 KO mice. In ensuing current-clamp experiments, we observed the presence of hyperpolarization-induced rebound burst firing in a subset of neurons in WT rats, as well as dopaminergic and non-dopaminergic neurons in TH-eGFP KI rats. Following the application of a pan-selective T-channel blocker TTA-P2, rebound bursting was significantly inhibited in all tested cells. In a behavioral assessment, the acute locomotor increase induced by a MK-801 (Dizocilpine) injection in WT mice was abolished in Ca V 3.1 KO mice, suggesting a tangible role for 3.1 T-type channels in drug response. We conclude that pharmacological targeting of Ca V 3.1 isoform of T-channels may be a novel approach for the treatment of disorders of mesolimbic reward system. Copyright © 2018. Published by Elsevier Ltd.

Serotonin-mediated modulation of Na+/K+ pump current in rat hippocampal CA1 pyramidal neurons.

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Zhang, Li Nan; Su, Su Wen; Guo, Fang; Guo, Hui Cai; Shi, Xiao Lu; Li, Wen Ya; Liu, Xu; Wang, Yong Li

2012-01-19

The aim of this study was to investigate whether serotonin (5-hydroxytryptamine, 5-HT) can modulate Na+/K+ pump in rat hippocampal CA1 pyramidal neurons. 5-HT (0.1, 1 mM) showed Na+/K+ pump current (Ip) densities of 0.40 ± 0.04, 0.34 ± 0.03 pA/pF contrast to 0.63 ± 0.04 pA/pF of the control of 0.5 mM strophanthidin (Str), demonstrating 5-HT-induced inhibition of Ip in a dose-dependent manner in hippocampal CA1 pyramidal neurons. The effect was partly attenuated by ondasetron, a 5-HT3 receptor (5-HT3R) antagonist, not by WAY100635, a 5-HT1AR antagonist, while 1-(3-Chlorophenyl) biguanide hydrochloride (m-CPBG), a 5-HT3R specific agonist, mimicked the effect of 5-HT on Ip. 5-HT inhibits neuronal Na+/K+ pump activity via 5-HT3R in rat hippocampal CA1 pyramidal neurons. This discloses novel mechanisms for the function of 5-HT in learning and memory, which may be a useful target to benefit these patients with cognitive disorder.

Reduction in LFP cross-frequency coupling between theta and gamma rhythms associated with impaired STP and LTP in a rat model of brain ischemia

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Tao eZhang

2013-04-01

Full Text Available The theta-gamma cross-frequency coupling (CFC in hippocampus was reported to reflect memory process. In this study, we measured the CFC of hippocampal local field potentials (LFPs in a two-vessel occlusion (2VO rat model, combined with both amplitude and phase properties and associated with short and long-term plasticity indicating the memory function. Male Wistar rats were used and a 2VO model was established. STP and LTP were recorded in hippocampal CA3-CA1 pathway after LFPs were collected in both CA3 and CA1. Based on the data of relative power spectra and phase synchronization, it suggested that both the amplitude and phase coupling of either theta or gamma rhythm were involved in modulating the neural network in 2VO rats. In order to determine whether the CFC was also implicated in neural impairment in 2VO rats, the coupling of CA3 theta–CA1 gamma was measured by both phase-phase coupling (n:m phase synchronization and phase-amplitude coupling. The attenuated CFC strength in 2VO rats implied the impaired neural communication in the coordination of theta-gamma entraining process. Moreover, compared with modulation index (MI a novel algorithm named cross frequency conditional mutual information (CF-CMI, was developed to focus on the coupling between theta phase and the phase of gamma amplitude. The results suggest that the reduced CFC strength probably attributed to the disruption of the phase of CA1 gamma envelop. In conclusion, it implied that the phase coupling and CFC of hippocampal theta and gamma played an important role in supporting functions of neural network. Furthermore, synaptic plasticity on CA3-CA1 pathway was reduced in line with the decreased CFC strength from CA3 to CA1. It partly supported our hypothesis that directional CFC indicator might probably be used as a measure of synaptic plasticity.

Calibration and validation of a physiologically based model for soman intoxication in the rat, marmoset, guinea pig and pig.

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Chen, Kaizhen; Seng, Kok-Yong

2012-09-01

A physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) model has been developed for low, medium and high levels of soman intoxication in the rat, marmoset, guinea pig and pig. The primary objective of this model was to describe the pharmacokinetics of soman after intravenous, intramuscular and subcutaneous administration in the rat, marmoset, guinea pig, and pig as well as its subsequent pharmacodynamic effects on blood acetylcholinesterase (AChE) levels, relating dosimetry to physiological response. The reactions modelled in each physiologically realistic compartment are: (1) partitioning of C(±)P(±) soman from the blood into the tissue; (2) inhibition of AChE and carboxylesterase (CaE) by soman; (3) elimination of soman by enzymatic hydrolysis; (4) de novo synthesis and degradation of AChE and CaE; and (5) aging of AChE-soman and CaE-soman complexes. The model was first calibrated for the rat, then extrapolated for validation in the marmoset, guinea pig and pig. Adequate fits to experimental data on the time course of soman pharmacokinetics and AChE inhibition were achieved in the mammalian models. In conclusion, the present model adequately predicts the dose-response relationship resulting from soman intoxication and can potentially be applied to predict soman pharmacokinetics and pharmacodynamics in other species, including human. Copyright © 2011 John Wiley & Sons, Ltd.

Reduced density and altered regulation of rat atrial L-type Ca2+ current in heart failure.

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Bond, Richard C; Bryant, Simon M; Watson, Judy J; Hancox, Jules C; Orchard, Clive H; James, Andrew F

2017-03-01

Constitutive regulation by PKA has recently been shown to contribute to L-type Ca 2+ current ( I CaL ) at the ventricular t-tubule in heart failure. Conversely, reduction in constitutive regulation by PKA has been proposed to underlie the downregulation of atrial I CaL in heart failure. The hypothesis that downregulation of atrial I CaL in heart failure involves reduced channel phosphorylation was examined. Anesthetized adult male Wistar rats underwent surgical coronary artery ligation (CAL, N =10) or equivalent sham-operation (Sham, N =12). Left atrial myocytes were isolated ~18 wk postsurgery and whole cell currents recorded (holding potential=-80 mV). I CaL activated by depolarizing pulses to voltages from -40 to +50 mV were normalized to cell capacitance and current density-voltage relations plotted. CAL cell capacitances were ~1.67-fold greater than Sham ( P ≤ 0.0001). Maximal I CaL conductance ( G max ) was downregulated more than 2-fold in CAL vs. Sham myocytes ( P 50% more effectively in CAL than in Sham so that differences in I CaL density were abolished. Differences between CAL and Sham G max were not abolished by calyculin A (100 nmol/l), suggesting that increased protein dephosphorylation did not account for I CaL downregulation. Treatment with either H-89 (10 μmol/l) or AIP (5 μmol/l) had no effect on basal currents in Sham or CAL myocytes, indicating that, in contrast to ventricular myocytes, neither PKA nor CaMKII regulated basal I CaL Expression of the L-type α 1C -subunit, protein phosphatases 1 and 2A, and inhibitor-1 proteins was unchanged. In conclusion, reduction in PKA-dependent regulation did not contribute to downregulation of atrial I CaL in heart failure. NEW & NOTEWORTHY Whole cell recording of L-type Ca 2+ currents in atrial myocytes from rat hearts subjected to coronary artery ligation compared with those from sham-operated controls reveals marked reduction in current density in heart failure without change in channel subunit

Distribution of rSlo Ca2+-activated K+ channels in rat astrocyte perivascular endfeet.

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Price, Diana L; Ludwig, Jeffrey W; Mi, Huaiyu; Schwarz, Thomas L; Ellisman, Mark H

2002-11-29

Evidence that Ca(2+)-activated K(+) (K(Ca)) channels play a role in cell volume changes and K(+) homeostasis led to a prediction that astrocytes would have K(Ca) channels near blood vessels in order to maintain K(+) homeostasis. Consistent with this thinking the present study demonstrates that rSlo K(Ca) channels are in glial cells of the adult rat central nervous system (CNS) and highly localized to specializations of astrocytes associated with the brain vasculature. Using confocal and thin-section electron microscopic immunolabeling methods the distribution of rSlo was examined in adult rat brain. Strong rSlo immunolabeling was present around the vasculature of most brain regions. Examination of dye-filled hippocampal astrocytes revealed rSlo immunolabeling polarized in astrocytic endfeet. Ultrastructural analysis confirmed that the rSlo staining was concentrated in astrocytic endfeet ensheathing capillaries as well as abutting the pia mater. Immunostaining within the endfeet was predominantly distributed at the plasma membrane directly adjacent to either the vascular basal lamina or the pial surface. The distribution of the aquaporin-4 (AQP-4) water channel was also examined using dye-filled hippocampal astrocytes. In confirmation of earlier reports, intense AQP-4 immunolabeling was generally observed at the perimeter of blood vessels, and coincided with perivascular endfeet and rSlo labeling. We propose that rSlo K(Ca) channels, with their sensitivity to membrane depolarization and intracellular calcium, play a role in the K(+) modulation of cerebral blood flow. Additional knowledge of the molecular and cellular machinery present at perivascular endfeet may provide insight into the structural and functional molecular elements responsible for the neuronal activity-dependent regulation of cerebral blood flow. Copyright 2002 Elsevier Science B.V.

Changes in functioning of rat submandibular salivary gland under streptozotocin-induced diabetes are associated with alterations of Ca2+ signaling and Ca2+ transporting pumps.

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Fedirko, N V; Kruglikov, I A; Kopach, O V; Vats, J A; Kostyuk, P G; Voitenko, N V

2006-03-01

Xerostomia and pathological thirst are troublesome complications of diabetes mellitus associated with impaired functioning of salivary glands; however, their cellular mechanisms are not yet determined. Isolated acinar cells were loaded with Ca2+ indicators fura-2/AM for measuring cytosolic Ca2+ concentration ([Ca2+]i) or mag-fura-2/AM-inside the endoplasmic reticulum (ER). We found a dramatic decrease in pilocarpine-stimulated saliva flow, protein content and amylase activity in rats after 6 weeks of diabetes vs. healthy animals. This was accompanied with rise in resting [Ca2+]i and increased potency of acetylcholine (ACh) and carbachol (CCh) but not norepinephrine (NE) to induce [Ca2+]i transients in acinar cells from diabetic animals. However, [Ca2+]i transients mediated by Ca2+ release from ER stores (induced by application of either ACh, CCh, NE, or ionomycin in Ca2+-free extracellular medium) were decreased under diabetes. Application of inositol-1,4,5-trisphosphate led to smaller Ca2+ release from ER under the diabetes. Both plasmalemma and ER Ca2+-ATPases activity was reduced and the latter showed the increased affinity to ATP under the diabetes. We conclude that the diabetes caused impairment of salivary cells functions that, on the cellular level, associates with Ca2+ overload, increased Ca2+-mobilizing ability of muscarinic but not adrenergic receptors, decreased Ca2+-ATPases activity and ER Ca2+ content.

Effect of exercise training on Ca²⁺ release units of left ventricular myocytes of spontaneously hypertensive rats.

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Carneiro-Júnior, M A; Quintão-Júnior, J F; Drummond, L R; Lavorato, V N; Drummond, F R; Amadeu, M A; Oliveira, E M; Felix, L B; Cruz, J S; Mill, J G; Natali, A J; Prímola-Gomes, T N

2014-11-01

In cardiomyocytes, calcium (Ca²⁺) release units comprise clusters of intracellular Ca²⁺ release channels located on the sarcoplasmic reticulum, and hypertension is well established as a cause of defects in calcium release unit function. Our objective was to determine whether endurance exercise training could attenuate the deleterious effects of hypertension on calcium release unit components and Ca²⁺ sparks in left ventricular myocytes of spontaneously hypertensive rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT) and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0% grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the ryanodine receptor type 2 (RyR2) and FK506 binding protein (FKBP12.6) increased (270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance exercise training reversed these changes by reducing RyR2 (230%) and normalizing FKBP12.6 gene expression (112%). Hypertension also increased the frequency of Ca²⁺ sparks (HC=7.61 ± 0.26 vs NC=4.79 ± 0.19 per 100 µm/s) and decreased its amplitude (HC=0.260 ± 0.08 vs NC=0.324 ± 0.10 ΔF/F0), full width at half-maximum amplitude (HC=1.05 ± 0.08 vs NC=1.26 ± 0.01 µm), total duration (HC=11.51 ± 0.12 vs NC=14.97 ± 0.24 ms), time to peak (HC=4.84 ± 0.06 vs NC=6.31 ± 0.14 ms), and time constant of decay (HC=8.68 ± 0.12 vs NC=10.21 ± 0.22 ms). These changes were partially reversed in HT rats (frequency of Ca²⁺ sparks=6.26 ± 0.19 µm/s, amplitude=0.282 ± 0.10 ΔF/F0, full width at half-maximum amplitude=1.14 ± 0.01 µm, total duration=13.34 ± 0.17 ms, time to peak=5.43 ± 0.08 ms, and time constant of decay=9.43 ± 0.15 ms). Endurance exercise training attenuated the deleterious effects of hypertension on calcium release

Protective effect of Na(+)/Ca (2+) exchange blocker KB-R7943 on myocardial ischemia-reperfusion injury in hypercholesterolemic rats.

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Lv, Yan; Ren, Yongkui; Sun, Lufan; Wang, Shaojun; Wei, Minjie; Jia, Dalin

2013-06-01

Reverse-mode activation of the Na(+)/Ca(2+) exchanger (NCX) during reperfusion following ischemia contributes to Ca(2+) overload and cardiomyocyte injury. KB-R7943, a selective reverse-mode NCX inhibitor, reduces lethal reperfusion injury under non-ischemic conditions. However, the effectiveness of this compound under ischemic conditions is unclear. In the present study, we studied the effects of KB-R7943 in an animal model of hyperlipidemia. We further assessed whether the K ATP (+) channels are involved in potential protective mechanisms of KB-R7943. Twelve rats were fed normal chow, while 48 animals were fed a high cholesterol diet. The hearts from the control and hypercholesterolemic rats were subjected to 25 min of global ischemia followed by a 120-min reperfusion. Before this, hearts from hypercholesterolemic rats either received no intervention (cholesterol control group) or were pre-treated with 1 μM KB-R7943 and 0.3 μM of K ATP (+) blocker glibenclamide or glibenclamide alone. The infarction sizes (triphenyltetrazolium assay) were 35 ± 5.0 % in the control group, 46 ± 8.7 % in the cholesterol control group (p KB-R7943 group (p KB-R7943 and glibenclamide group, and 47 ± 8.5 % in the glibenclamide group (p KB-R7943 attenuated the magnitude of cell apoptosis (p KB-R7943 reduces the infarction size and apoptosis in hyperlipidemic animals through the activation of K ATP (+) channels.

Interaction between the medial prefrontal cortex and hippocampal CA1 area is essential for episodic-like memory in rats.

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Chao, Owen Y; Nikolaus, Susanne; Lira Brandão, Marcus; Huston, Joseph P; de Souza Silva, Maria A

2017-05-01

The interplay between medial prefrontal cortex (mPFC) and hippocampus, particularly the hippocampal CA3 area, is critical for episodic memory. To what extent the mPFC also interacts with the hippocampus CA1 subregion still requires elucidation. To investigate this issue, male rats received unilateral N-methyl- D -aspartate lesions of the mPFC together with unilateral lesions of the hippocampal CA1 area, either in the same (control) or in the opposite hemispheres (disconnection). They underwent an episodic-like memory test, combining what-where-when information, and separate tests for novel object preference (what), object place preference (where) and temporal order memory (when). Compared to controls, the disconnected mPFC-CA1 rats exhibited disrupted episodic-like memory with an impaired integration of the what-where-when elements. Both groups showed intact memories for what and when, while only the control group showed intact memory for where. These findings suggest that the functional interaction of the mPFC-CA1 circuit is crucial for the processing of episodic memory and, in particular, for the integration of the spatial memory component. Copyright © 2017 Elsevier Inc. All rights reserved.

Lithium-induced inhibition of Na-K ATPase and Ca ATPase activities in rat brain synaptosome.

Science.gov (United States)

Cho, Y. W.

1995-01-01

To explore the action mechanism of lithium in the brain, the author investigated the effects of lithium on Na-K ATPase and Ca ATPase in rat brain synaptosomes prepared from forebrains by the method of Booth and Clark. The activities of Na-K ATPase and Ca ATPase were assayed by the level of inorganic phosphate liberated from the hydrolysis of ATP. Lithium at the optimum therapeutic concentration of 1 mM decreased the activity of Na-K ATPase from the control value of 19.08 +/- 0.29 to 18.27 +/- 0.10 micromoles Pi/mg protein/h and also reduced the activity of Ca ATPase from 6.38 +/- 0.12 to 5.64 +/- 0.12 micromoles Pi/mg protein/h. The decreased activity of Na-K ATPase will decrease the rate of Ca2+ efflux, probably via an Na-Ca exchange mechanism and will increase the rate of Ca2+ entry by the depolarization of nerve terminals. The reduced activity of Ca ATPase will result in the decreased efflux of Ca2+. As a Conclusion, it can be speculated that lithium elevates the intrasynaptosomal Ca2+ concentration via inhibition of the activities of Na-K ATPase and Ca ATPase, and this increased [Ca2+]i will cause the release of neurotransmitters and neurological effects of lithium. PMID:7598829

Hydrogen sulfide regulates intracellular Ca2+ concentration in endothelial cells from excised rat aorta.

Science.gov (United States)

Moccia, Francesco; Bertoni, Giuseppe; Pla, Alessandra Florio; Dragoni, Silvia; Pupo, Emanuela; Merlino, Annalisa; Mancardi, Daniele; Munaron, Luca; Tanzi, Franco

2011-09-01

Hydrogen sulphide (H2S) is a recently discovered gasotransmitter that may regulate a growing number of endothelial functions, including nitric oxide (NO) release, proliferation, adhesion and migration, which are the key steps of angiogenesis. The mechanism whereby H2S impacts on endothelial physiology is still unclear: however, the aforementioned processes are driven by an increase in intracellular Ca2+ concentration ([Ca2+]i). In the present study, we exploited the excised rat aorta to gain insights into the regulation of [Ca2+]i by H2S within in situ endothelial cells (ECs). Sodium hydrosulphide (NaHS), a H2S donor, caused an elevation in [Ca2+]i, which disappeared in absence of extracellular Ca2+. NaHSinduced Ca2+ inflow was sensitive to high doses of Gd3+, but not BTP-2. Inhibition of the reverse-mode of the Na+-Ca2+ exchanger (NCX), with KB-R7943 or upon removal of extracellular Na+, abrogated the Ca2+ response to NaHS. Moreover, NaHS-elicited Ca2+ entry was significantly reduced by TEA and glybenclamide, which hinted at the involvement of ATP-dependent K+ (KATP) channels. Conversely, NaHS-evoked Ca2+ signal was not affected by the reducing agent, dithiothreitol. Acute addition of NaHS hindered both Ca2+ release and Ca2+ entry induced by ATP, a physiological agonist of ECs. Consistently, inhibition of endogenous H2S synthesis with DL-propargylglycine impaired ATP-induced Ca2+ inflow, whereas it did not affect Ca2+ mobilization. These data provide the first evidence that H2S may stimulate Ca2+ influx into ECs by recruiting the reverse-mode of NCX and KATP channels. In addition, they show that such gasotransmitter may modulate the Ca2+ signals elicited by physiological stimuli in intact endothelium.

Detection of Ca2+-dependent acid phosphatase activity identifies neuronal integrity in damaged rat central nervous system after application of bacterial melanin

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Tigran R Petrosyan

2016-01-01

Full Text Available The study aims to confirm the neuroregenerative effects of bacterial melanin (BM on central nervous system injury using a special staining method based on the detection of Ca2+-dependent acid phosphatase activity. Twenty-four rats were randomly assigned to undergo either unilateral destruction of sensorimotor cortex (group I; n = 12 or unilateral rubrospinal tract transection at the cervical level (C3–4 (group II; n = 12. In each group, six rats were randomly selected after surgery to undergo intramuscular injection of BM solution (BM subgroup and the remaining six rats were intramuscularly injected with saline (saline subgroup. Neurological testing confirmed that BM accelerated the recovery of motor function in rats from both BM and saline subgroups. Two months after surgery, Ca2+-dependent acid phosphatase activity detection in combination with Chilingarian's calcium adenoside triphosphate method revealed that BM stimulated the sprouting of fibers and dilated the capillaries in the brain and spinal cord. These results suggest that BM can promote the recovery of motor function of rats with central nervous system injury; and detection of Ca2+-dependent acid phosphatase activity is a fast and easy method used to study the regeneration-promoting effects of BM on the injured central nervous system.

Reduced sarcoplasmic reticulum content of releasable Ca2+ in rat soleus muscle fibres after eccentric contractions

DEFF Research Database (Denmark)

Nielsen, J S; Sahlin, K; Ørtenblad, N

2007-01-01

AIM: The purpose was to evaluate the effects of fatiguing eccentric contractions (EC) on calcium (Ca2+) handling properties in mammalian type I muscles. We hypothesized that EC reduces both endogenous sarcoplasmic reticulum (SR) content of releasable Ca2+ (eSRCa2+) and myofibrillar Ca2+ sensitivity....... METHODS: Isolated rat soleus muscles performed 30 EC bouts. Single fibres were isolated from the muscle and after mechanical removal of sarcolemma used to measure eSRCa2+, rate of SR Ca2+ loading and myofibrillar Ca2+ sensitivity. RESULTS: Following EC maximal force in whole muscle was reduced by 30......% and 16/100 Hz force ratio by 33%. The eSRCa2+ in fibres from non-stimulated muscles was 45 +/- 5% of the maximal loading capacity. After EC, eSRCa2+ per fibre CSA decreased by 38% (P = 0.05), and the maximal capacity of SR Ca2+ loading was depressed by 32%. There were no effects of EC on either...

Mucin 4 Gene Silencing Reduces Oxidative Stress and Calcium Oxalate Crystal Formation in Renal Tubular Epithelial Cells Through the Extracellular Signal-Regulated Kinase Signaling Pathway in Nephrolithiasis Rat Model

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Ling Sun

2018-05-01

Full Text Available Background/Aims: Nephrolithiasis plagues a great number of patients all over the world. Increasing evidence shows that the extracellular signal-regulated kinase (ERK signaling pathway and renal tubular epithelial cell (RTEC dysfunction and attrition are central to the pathogenesis of kidney diseases. Mucin 4 (MUC4 is reported as an activator of ERK signaling pathway in epithelial cells. In this study, using rat models of calcium oxalate (CaOx nephrolithiasis, the present study aims to define the roles of MUC4 and ERK signaling pathway as contributors to oxidative stress and CaOx crystal formation in RTEC. Methods: Data sets of nephrolithiasis were searched using GEO database and a heat flow map was drawn. Then MUC4 function was predicted. Wistar rats were prepared for the purpose of model establishment of ethylene glycol and ammonium chloride induced CaOx nephrolithiasis. In order to assess the detailed regulatory mechanism of MUC4 silencing on the ERK signaling pathway and RTEC, we used recombinant plasmid to downregulate MUC4 expression in Wistar rat-based models. Samples from rat urine, serum and kidney tissues were reviewed to identify oxalic acid and calcium contents, BUN, Cr, Ca2+ and P3+ levels, calcium crystal formation in renal tubules and MUC4 positive expression rate. Finally, RT-qPCR, Western blot analysis, and ELISA were employed to access oxidative stress state and CaOx crystal formation in RTEC. Results: Initially, MUC4 was found to have an influence on the process of nephrolithiasis. MUC4 was upregulated in the CaOx nephrolithiasis model rats. We proved that the silencing of MUC4 triggered the inactivation of ERK signaling pathway. Following the silencing of MUC4 or the inhibition of ERK signaling pathway, the oxalic acid and calcium contents in rat urine, BUN, Cr, Ca2+ and P3+ levels in rat serum, p-ERK1/2, MCP-1 and OPN expressions in RTEC and H2O2 and MDA levels in the cultured supernatant were downregulated, but the GSH

Electrophysiological characterization of activation state-dependent Ca(v)2 channel antagonist TROX-1 in spinal nerve injured rats.

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Patel, R; Rutten, K; Valdor, M; Schiene, K; Wigge, S; Schunk, S; Damann, N; Christoph, T; Dickenson, A H

2015-06-25

Prialt, a synthetic version of Ca(v)2.2 antagonist ω-conotoxin MVIIA derived from Conus magus, is the first clinically approved voltage-gated calcium channel blocker for refractory chronic pain. However, due to the narrow therapeutic window and considerable side effects associated with systemic dosing, Prialt is only administered intrathecally. N-triazole oxindole (TROX-1) is a novel use-dependent and activation state-selective small-molecule inhibitor of Ca(v)2.1, 2.2 and 2.3 calcium channels designed to overcome the limitations of Prialt. We have examined the neurophysiological and behavioral effects of blocking calcium channels with TROX-1. In vitro, TROX-1, in contrast to state-independent antagonist Prialt, preferentially inhibits Ca(v)2.2 currents in rat dorsal root ganglia (DRG) neurons under depolarized conditions. In vivo electrophysiology was performed to record from deep dorsal horn lamina V/VI wide dynamic range neurons in non-sentient spinal nerve-ligated (SNL) and sham-operated rats. In SNL rats, spinal neurons exhibited reduced responses to innocuous and noxious punctate mechanical stimulation of the receptive field following subcutaneous administration of TROX-1, an effect that was absent in sham-operated animals. No effect was observed on neuronal responses evoked by dynamic brushing, heat or cold stimulation in SNL or sham rats. The wind-up response of spinal neurons following repeated electrical stimulation of the receptive field was also unaffected. Spinally applied TROX-1 dose dependently inhibited mechanically evoked neuronal responses in SNL but not sham-operated rats, consistent with behavioral observations. This study confirms the pathological state-dependent actions of TROX-1 through a likely spinal mechanism and reveals a modality selective change in calcium channel function following nerve injury. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

[Conditions required for appearance of a double response to a single-shock stimulation of Schaffer collaterals in hippocampal field CA1 in freely moving rats].

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Zosimovskiĭ, V A; Korshunov, V A; Markevich, V A

2007-01-01

Schaffer collateral stimulation with a single current impulse can evoke a double response in hippocampal field CA1 of freely moving rats. The late response appears as a population excitatory postsynaptic potential with a preceding short-term potential (frequently biphasic) only after the early population spike and is time-locked to it. The wave shape and polarity of the late response, its latency with respect to the peak of the early population spike suggest that the excitation wave produced in the CA1 field by the stimulation of Schaffer collaterals passes across the entorhinal cortex and returns to the CA1 directly via the perforant path fibers. In waking rat, the medium-intensity stimulation of Schaffer collaterals (able to evoke in the CA1 an early population spike of sufficiently high amplitude) usually does not result in the appearance of the late response. However, similar stimulation becomes efficient after the tetanization of Schaffer collaterals, under conditions of the long-term potentiation of the early population spike. Moreover, the late response occurrence is facilitated in a rat falling asleep after the development in the CA1 of high-amplitude low-frequency EEG oscillations typical for the slow-wave sleep and in a sleeping rat independently of the EEG pattern.

Housing under the pyramid reduces susceptibility of hippocampal CA3 pyramidal neurons to prenatal stress in the developing rat offspring.

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Murthy, Krishna Dilip; George, Mitchel Constance; Ramasamy, Perumal; Mustapha, Zainal Arifin

2013-12-01

Mother-offspring interaction begins before birth. The foetus is particularly vulnerable to environmental insults and stress. The body responds by releasing excess of the stress hormone cortisol, which acts on glucocorticoid receptors. Hippocampus in the brain is rich in glucocorticoid receptors and therefore susceptible to stress. The stress effects are reduced when the animals are placed under a model wooden pyramid. The present study was to first explore the effects of prenatal restraint-stress on the plasma corticosterone levels and the dendritic arborisation of CA3 pyramidal neurons in the hippocampus of the offspring. Further, to test whether the pyramid environment would alter these effects, as housing under a pyramid is known to reduce the stress effects, pregnant Sprague Dawley rats were restrained for 9 h per day from gestation day 7 until parturition in a wire-mesh restrainer. Plasma corticosterone levels were found to be significantly increased. In addition, there was a significant reduction in the apical and the basal total dendritic branching points and intersections of the CA3 hippocampal pyramidal neurons. The results thus suggest that, housing in the pyramid dramatically reduces prenatal stress effects in rats.

Evaluation of protein acylation agents for the radioiodination of peptides: Application to labelling octreotide

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Zalutsky, M.; Vaidyanathan, G.

2002-01-01

The purpose of this study was to investigate the utility of two acylation agents originally developed for protein labelling - N-succinimidyl 3-[ 131 I]iodobenzoate and N-succinimidyl 5-[ 131 I]iodopyridine-3- carboxylate - for the radioiodination of peptides. Because of the widespread interest in imaging and treating malignancies that overexpress somatostatin receptors, octreotide was selected as the model peptide. Using these reagents, octreotide was coupled to 3-iodobenzoyl and 3-iodonicotinoyl templates, yielding [N-(3-iodobenzoyl)- D-Phe 1 ]octreotide (IBO) and [N-(3-iodonicotinoyl)-D-Phe 1 ]octreotide (INO), respectively. The IC 50 values for the binding of IBO and INO to somatostatin receptor expressing CA20948 rat pancreatic tumour membranes were 0.90 nM and 0.13 nM, respectively, compared with 0.35 nM for octreotide itself. Yields for the preparation of [ 131 I]IBO and [ 131 I]INO from N-succinimidyl 3-[ 131 I]iodobenzoate and N-succinimidyl 5-[ 131 I]iodopyridine-3- carboxylate, were 35-50%. In vitro assays with AR42J rat pancreatic tumour cells demonstrated considerably higher receptor-specific retention of cell-internalized radioiodine activity for [ 131 I]INO compared with [ 125 I]IBO. A tissue distribution study with both conjugates revealed low levels of activity in the thyroid, consistent with a low degree of deiodination of these radioiodinated peptide conjugates. (author)

An inhibitory effect of extracellular Ca2+ on Ca2+-dependent exocytosis.

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Wei Xiong

Full Text Available AIM: Neurotransmitter release is elicited by an elevation of intracellular Ca(2+ concentration ([Ca(2+](i. The action potential triggers Ca(2+ influx through Ca(2+ channels which causes local changes of [Ca(2+](i for vesicle release. However, any direct role of extracellular Ca(2+ (besides Ca(2+ influx on Ca(2+-dependent exocytosis remains elusive. Here we set out to investigate this possibility on rat dorsal root ganglion (DRG neurons and chromaffin cells, widely used models for studying vesicle exocytosis. RESULTS: Using photolysis of caged Ca(2+ and caffeine-induced release of stored Ca(2+, we found that extracellular Ca(2+ inhibited exocytosis following moderate [Ca(2+](i rises (2-3 µM. The IC(50 for extracellular Ca(2+ inhibition of exocytosis (ECIE was 1.38 mM and a physiological reduction (∼30% of extracellular Ca(2+ concentration ([Ca(2+](o significantly increased the evoked exocytosis. At the single vesicle level, quantal size and release frequency were also altered by physiological [Ca(2+](o. The calcimimetics Mg(2+, Cd(2+, G418, and neomycin all inhibited exocytosis. The extracellular Ca(2+-sensing receptor (CaSR was not involved because specific drugs and knockdown of CaSR in DRG neurons did not affect ECIE. CONCLUSION/SIGNIFICANCE: As an extension of the classic Ca(2+ hypothesis of synaptic release, physiological levels of extracellular Ca(2+ play dual roles in evoked exocytosis by providing a source of Ca(2+ influx, and by directly regulating quantal size and release probability in neuronal cells.

Salvia miltiorrhiza Induces Tonic Contraction of the Lower Esophageal Sphincter in Rats via Activation of Extracellular Ca2+ Influx

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Ching-Chung Tsai

2015-08-01

Full Text Available Up to 40% of patients with gastroesophageal reflux disease (GERD suffer from proton pump inhibitor refractory GERD but clinically the medications to strengthen the lower esophageal sphincter (LES to avoid irritating reflux are few in number. This study aimed to examine whether Salvia miltiorrhiza (SM extracts induce tonic contraction of rat LES ex vivo and elucidate the underlying mechanisms. To investigate the mechanism underlying the SM extract-induced contractile effects, rats were pretreated with atropine (a muscarinic receptor antagonist, tetrodotoxin (a sodium channel blocker, nifedipine (a calcium channel blocker, and Ca2+-free Krebs-Henseleit solution with ethylene glycol tetraacetic acid (EGTA, followed by administration of cumulative dosages of SM extracts. SM extracts induced dose-related tonic contraction of the LES, which was unaffected by tetrodotoxin, atropine, or nifedipine. However, the SM extract-induced LES contraction was significantly inhibited by Ca2+-free Krebs-Henseleit solution with EGTA. Next, SM extracts significantly induce extracellular Ca2+ entry into primary LES cells in addition to intracellular Ca2+ release and in a dose-response manner. Confocal fluorescence microscopy showed that the SM extracts consistently induced significant extracellular Ca2+ influx into primary LES cells in a time-dependent manner. In conclusion, SM extracts could induce tonic contraction of LES mainly through the extracellular Ca2+ influx pathway.

Lycopene depresses glutamate release through inhibition of voltage-dependent Ca2+ entry and protein kinase C in rat cerebrocortical nerve terminals.

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Lu, Cheng-Wei; Hung, Chi-Feng; Jean, Wei-Horng; Lin, Tzu-Yu; Huang, Shu-Kuei; Wang, Su-Jane

2018-05-01

Lycopene is a natural dietary carotenoid that was reported to exhibit a neuroprotective profile. Considering that excitotoxicity and cell death induced by glutamate are involved in many brain disorders, the effect of lycopene on glutamate release in rat cerebrocortical nerve terminals and the possible mechanism involved in such effect was investigated. We observed here that lycopene inhibited 4-aminopyridine (4-AP)-evoked glutamate release and intrasynaptosomal Ca 2+ concentration elevation. The inhibitory effect of lycopene on 4-AP-evoked glutamate release was markedly reduced in the presence of the Ca v 2.2 (N-type) and Ca v 2.1 (P/Q-type) channel blocker ω-conotoxin MVIIC, but was insensitive to the intracellular Ca 2+ -release inhibitors dantrolene and CGP37157. Furthermore, in the presence of the protein kinase C inhibitors GF109203X and Go6976, the action of lycopene on evoked glutamate release was prevented. These results are the first to suggest that lycopene inhibits glutamate release from rat cortical synaptosomes by suppressing presynaptic Ca 2+ entry and protein kinase C activity.

Effect of acetylcholine receptors on the pain-related electrical activities in the hippocampal CA3 region of morphine-addicted rats

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Li, Guan Zeng; Liu, Zhe Hui; Wei, XinYa; Zhao, Pan; Yang, Chun Xiao; Xu, Man Ying

2015-01-01

Objective(s): To determine the effect of acetylcholine (ACh), pilocarpine, and atropine on pain evoked responses of pain excited neurons (PEN) and pain inhibited neurons (PIN) in hippocampal CA3 region of morphine addicted rats. Materials and Methods: Female Wistar rats, weighing between 230-260 g were used in this study. Morphine addicted rats were generated by subcutaneous injection of increasing concentrations of morphine hydrochloride for six days. Trains of electrical impulses applied to...

Cinnamic Acid Derivatives Enhance the Efficacy of Transarterial Embolization in a Rat Model of Hepatocellular Carcinoma

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Wilkins, Luke R., E-mail: lrw6n@virginia.edu [University of Virginia Health Systems, Department of Radiology and Medical Imaging (United States); Brautigan, David L., E-mail: db8g@virginia.edu [University of Virginia, Department of Microbiology, Immunology, and Cancer Biology (United States); Wu, Hanping, E-mail: hanpingwumd@gmail.com [University Hospitals of Cleveland, Case Western Reserve University, Department of Radiology (United States); Yarmohammadi, Hooman, E-mail: yar.hooman@gmail.com [Memorial Sloan-Kettering Cancer Center, Department of Radiology (United States); Kubicka, Ewa, E-mail: emk6d@virginia.edu [University of Virginia, Department of Microbiology, Immunology, and Cancer Biology (United States); Serbulea, Vlad, E-mail: vs9ck@virginia.edu; Leitinger, Norbert, E-mail: nl2q@virginia.edu [University of Virginia, Department of Pharmacology (United States); Liu, Wendy, E-mail: wendy.liu@uhhospitals.org [University Hospitals of Cleveland, Case Western Reserve University, Department of Pathology (United States); Haaga, John R., E-mail: john.haaga@uhhospitals.org [University Hospitals of Cleveland, Case Western Reserve University, Department of Radiology (United States)

2017-03-15

IntroductionWe hypothesize that the combination of transarterial embolization (TAE) plus inhibition of lactate export will limit anaerobic metabolism and reduce tumor survival compared to TAE alone. The purpose of this study was to test this hypothesis in a rat model of hepatocellular carcinoma (HCC).MethodsRat N1-S1 hepatoma cells were assayed in vitro using the Seahorse XF analyzer to measure extracellular acidification (lactate excretion) comparing effects of the addition of caffeic acid (CA) or ferulic acid (FA) or UK-5099 with control. Monocarboxylate transporter Slc16a3 was knocked down by RNAi. N1S1 tumors were orthotopically implanted in rats and 4 groups evaluated: (1) Control, (2) TAE-only, (3) TAE plus CA, and (4) TAE plus FA. Tumor size was determined by ultrasound and analyzed by repeated measures statistics. Tumors harvested at 4 weeks were examined by microscopy.ResultsSeahorse assays showed that CA and FA caused a significant reduction by >90% in lactate efflux by N1S1 tumor cells (p < 0.01). Knockdown of Slc16a3 prevented inhibition by CA. In vivo tumors grew 30-fold in volume over 4 weeks in untreated controls. By comparison, TAE resulted in near cessation of growth (10% in 4-week time period). However, both TAE + CA and TAE + FA caused a significant reduction of tumor volumes (87 and 72%, respectively) compared to control and TAE (p < 0.05). Pathologic evaluation revealed residual tumor in the TAE group but no residual viable tumor cells in the TAE + CA and TAE + FA groups.ConclusionAddition of CA or FA enhances the effectiveness of TAE therapy for HCC in part by blocking lactate efflux.

Cinnamic Acid Derivatives Enhance the Efficacy of Transarterial Embolization in a Rat Model of Hepatocellular Carcinoma

International Nuclear Information System (INIS)

Wilkins, Luke R.; Brautigan, David L.; Wu, Hanping; Yarmohammadi, Hooman; Kubicka, Ewa; Serbulea, Vlad; Leitinger, Norbert; Liu, Wendy; Haaga, John R.

2017-01-01

IntroductionWe hypothesize that the combination of transarterial embolization (TAE) plus inhibition of lactate export will limit anaerobic metabolism and reduce tumor survival compared to TAE alone. The purpose of this study was to test this hypothesis in a rat model of hepatocellular carcinoma (HCC).MethodsRat N1-S1 hepatoma cells were assayed in vitro using the Seahorse XF analyzer to measure extracellular acidification (lactate excretion) comparing effects of the addition of caffeic acid (CA) or ferulic acid (FA) or UK-5099 with control. Monocarboxylate transporter Slc16a3 was knocked down by RNAi. N1S1 tumors were orthotopically implanted in rats and 4 groups evaluated: (1) Control, (2) TAE-only, (3) TAE plus CA, and (4) TAE plus FA. Tumor size was determined by ultrasound and analyzed by repeated measures statistics. Tumors harvested at 4 weeks were examined by microscopy.ResultsSeahorse assays showed that CA and FA caused a significant reduction by >90% in lactate efflux by N1S1 tumor cells (p < 0.01). Knockdown of Slc16a3 prevented inhibition by CA. In vivo tumors grew 30-fold in volume over 4 weeks in untreated controls. By comparison, TAE resulted in near cessation of growth (10% in 4-week time period). However, both TAE + CA and TAE + FA caused a significant reduction of tumor volumes (87 and 72%, respectively) compared to control and TAE (p < 0.05). Pathologic evaluation revealed residual tumor in the TAE group but no residual viable tumor cells in the TAE + CA and TAE + FA groups.ConclusionAddition of CA or FA enhances the effectiveness of TAE therapy for HCC in part by blocking lactate efflux.

Therapeutic Effects of TianDiJingWan on the Aβ25–35-Induced Alzheimer’s Disease Model Rats

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Zhijie Li

2015-01-01

Full Text Available The main purpose of this study was to demonstrate the therapeutic effects and mechanism of TDJW, a modern Chinese medicine prescription developed based on the basic traditional Chinese medicine theory of “tonifying the kidney essence,” on the Aβ25–35-induced AD rats. The AD model was established by the intracerebroventricular administrations of Aβ25–35 into the hippocampus CA1 tissue of SD male rats. 72 rats were randomly divided into six groups: sham operation, AD model, donepezil, high TDJW group, medium TDJW group, and low TDJW group. After oral administration of TDJW, the results of Morris water maze and step-down test showed that the learning and memory abilities of AD rats were significantly improved. And biochemical measurement demonstrated that Ach and Glu in hippocampus tissues of AD rats were increased as well. Moreover, the Aβ deposits and p-Tau aggregations in hippocampus CA1 tissues of AD rats were attenuated as observed in the micrographs of immunohistochemistry study, and the results of ELISA indicated that the expressions of TNF-α, IL-1β, and IL-6 in hippocampus tissues were significantly decreased. In conclusion, the present study demonstrated that TDJW could be used as a promising therapeutic agent for the clinical applications of AD treatment in patients.

Distribution of calcium channel Ca(V)1.3 immunoreactivity in the rat spinal cord and brain stem.

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Sukiasyan, N; Hultborn, H; Zhang, M

2009-03-03

The function of local networks in the CNS depends upon both the connectivity between neurons and their intrinsic properties. An intrinsic property of spinal motoneurons is the presence of persistent inward currents (PICs), which are mediated by non-inactivating calcium (mainly Ca(V)1.3) and/or sodium channels and serve to amplify neuronal input signals. It is of fundamental importance for the prediction of network function to determine the distribution of neurons possessing the ion channels that produce PICs. Although the distribution pattern of Ca(V)1.3 immunoreactivity (Ca(V)1.3-IR) has been studied in some specific central nervous regions in some species, so far no systematic investigations have been performed in both the rat spinal cord and brain stem. In the present study this issue was investigated by immunohistochemistry. The results indicated that the Ca(V)1.3-IR neurons were widely distributed across different parts of the spinal cord and the brain stem although with variable labeling intensities. In the spinal gray matter large neurons in the ventral horn (presumably motoneurons) tended to display higher levels of immunoreactivity than smaller neurons in the dorsal horn. In the white matter, a subset of glial cells labeled by an oligodendrocyte marker was also Ca(V)1.3-positive. In the brain stem, neurons in the motor nuclei appeared to have higher levels of immunoreactivity than those in the sensory nuclei. Moreover, a number of nuclei containing monoaminergic cells, for example the locus coeruleus, were also strongly immunoreactive. Ca(V)1.3-IR was consistently detected in the neuronal perikarya regardless of the neuronal type. However, in the large neurons in the spinal ventral horn and the cranial motor nuclei the Ca(V)1.3-IR was clearly detectable in first and second order dendrites. These results indicate that in the rat spinal cord and brain stem Ca(V)1.3 is probably a common calcium channel used by many kinds of neurons to facilitate the neuronal

Cannabinoids disrupt memory encoding by functionally isolating hippocampal CA1 from CA3.

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Roman A Sandler

2017-07-01

Full Text Available Much of the research on cannabinoids (CBs has focused on their effects at the molecular and synaptic level. However, the effects of CBs on the dynamics of neural circuits remains poorly understood. This study aims to disentangle the effects of CBs on the functional dynamics of the hippocampal Schaffer collateral synapse by using data-driven nonparametric modeling. Multi-unit activity was recorded from rats doing an working memory task in control sessions and under the influence of exogenously administered tetrahydrocannabinol (THC, the primary CB found in marijuana. It was found that THC left firing rate unaltered and only slightly reduced theta oscillations. Multivariate autoregressive models, estimated from spontaneous spiking activity, were then used to describe the dynamical transformation from CA3 to CA1. They revealed that THC served to functionally isolate CA1 from CA3 by reducing feedforward excitation and theta information flow. The functional isolation was compensated by increased feedback excitation within CA1, thus leading to unaltered firing rates. Finally, both of these effects were shown to be correlated with memory impairments in the working memory task. By elucidating the circuit mechanisms of CBs, these results help close the gap in knowledge between the cellular and behavioral effects of CBs.

S-glutathionylation of troponin I (fast) increases contractile apparatus Ca2+ sensitivity in fast-twitch muscle fibres of rats and humans.

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Mollica, J P; Dutka, T L; Merry, T L; Lamboley, C R; McConell, G K; McKenna, M J; Murphy, R M; Lamb, G D

2012-03-15

Oxidation can decrease or increase the Ca2+ sensitivity of the contractile apparatus in rodent fast-twitch (type II) skeletal muscle fibres, but the reactions and molecular targets involved are unknown. This study examined whether increased Ca2+ sensitivity is due to S-glutathionylation of particular cysteine residues. Skinned muscle fibres were directly activated in heavily buffered Ca2+ solutions to assess contractile apparatus Ca2+ sensitivity. Rat type II fibres were subjected to S-glutathionylation by successive treatments with 2,2′-dithiodipyridine (DTDP) and glutathione (GSH), and displayed a maximal increase in pCa50 (−log10 [Ca2+] at half-maximal force) of ∼0.24 pCa units, with little or no effect on maximum force or Hill coefficient. Partial similar effect was produced by exposure to oxidized gluthathione (GSSG, 10 mM) for 10 min at pH 7.1, and near-maximal effect by GSSG treatment at pH 8.5. None of these treatments significantly altered Ca2+ sensitivity in rat type I fibres. Western blotting showed that both the DTDP–GSH and GSSG–pH 8.5 treatments caused marked S-glutathionylation of the fast troponin I isoform (TnI(f)) present in type II fibres, but not of troponin C (TnC) or myosin light chain 2. Both the increased Ca2+ sensitivity and glutathionylation of TnI(f) were blocked by N-ethylmaleimide (NEM). S-nitrosoglutathione (GSNO) also increased Ca2+ sensitivity, but only in conditions where it caused S-glutathionylation of TnI(f). In human type II fibres from vastus lateralis muscle, DTDP–GSH treatment also caused similar increased Ca2+ sensitivity and S-glutathionylation of TnI(f). When the slow isoform of TnI in type I fibres of rat was partially substituted (∼30%) with TnI(f), DTDP–GSH treatment caused a significant increase in Ca2+ sensitivity (∼0.08 pCa units). TnIf in type II fibres from toad and chicken muscle lack Cys133 present in mammalian TnIf, and such fibres showed no change in Ca2+ sensitivity with DTDP–GSH nor any S

Mass yield distributions for the reactions Ca+Ca, Nb+Nb and Ca+Ca at E/A=800 MeV in the molecular-dynamical model

International Nuclear Information System (INIS)

Kiselev, S.M.

1987-01-01

Mass yield distributions obtained on the basis of the molecular-dynamical model are presented for the Ca+Ca, Nb+Nb reactions at E/A=400 MeV and Ca+Ca reaction at E/A=800 MeV. For the fragments with masses upto quarter of the mass of initial nucleus the model predicts a power law for mass spectra with almost the same value of the exponent. Such the behaviour is roughly a result of the superposition of the fireball breakup and the disintegration of spectator regions rather than the evidence of a liquid-gas-like phase transition in hot nuclear matter

Alterations in Ca2+-dependent and Ca2+-independent release of catecholamines in preparations of rat brain produced by ethanol treatment in vivo

International Nuclear Information System (INIS)

Lynch, M.A.; Pagonis, C.; Samuel, D.; Littleton, J.M.

1985-01-01

Compared to preparations from control animals, superfused striatal slice preparations from brains of rats treated chronically with ethanol released a significantly greater fraction of stored [ 3 H] dopamine on depolarisation in 40 mM K + . Similarly, the electrically-evoked release of [ 3 H]-norepinephrine from cortical slices and of [ 3 H]-dopamine from striatal slices is also increased, although with this mechanism of depolarisation the change is significant only in the case of [ 3 H] norepinephrine release. In contrast to this tendency to enhancement of Ca 2+ -dependent depolarisation-induced release, a reduced fraction of stored [ 3 H]-catecholamines was released from these preparations by the indirect sympathomimetics tyramine and (+)-amphetamine. The catecholamine release induced by these indirect sympathomimetics is largely independent of external Ca 2+ and the results are interpreted as suggesting that chronic alcohol treatment changes the distribution of catecholamine neurotransmitters between storage pools in the nerve terminal which do or do not require Ca 2+ entry for release

Conditions required for the appearance of double responses in hippocampal field CA1 to application of single stimuli to Shäffer collaterals in freely moving rats.

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Zosimovskii, V A; Korshunov, V A; Markevich, V A

2008-03-01

Stimulation of Shäffer collaterals with single current impulses could evoke double responses in hippocampal field CA1 in freely moving rats. The late response - the population excitatory postsynaptic potential with a preceding transient potential, often biphasic - occurred only after an early population spike and was time-locked to it. The shape characteristics of the late response, its polarity, and its latent period relative to the early population spike suggest that stimulation of Shäffer collaterals gives rise, in CA1, to a wave of excitation which passes through the entorhinal cortex and returns to CA1 directly via fibers of the perforant path. In conscious rats, medium-strength stimulation of Shäffer collaterals, sufficient to evoke a quite early population spike in CA1, did not usually lead to the appearance of a late response; the same stimulation became effective after tetanization of Shäffer collaterals in conditions of long-term potentiation of the early population spike. Furthermore, the appearance of the late response was facilitated in rats falling asleep on the background of high-amplitude, low-frequency EEG oscillations in CA1 characteristic of slow-wave sleep, as well as in sleeping rats, regardless of the EEG pattern.

Depolarization-dependent 45Ca uptake by synaptosomes of rat cerebral cortex is enhanced by L-triiodothyronine

International Nuclear Information System (INIS)

Mason, G.A.; Walker, C.H.; Prange, A.J. Jr.

1990-01-01

Depolarization-induced release of neurotransmitters and other secretions from nerve endings is triggered by the rapid entry of Ca++ through voltage-sensitive channels. Calcium entry is thought to occur in two distinct phases or processes: a fast-phase response to an action potential, which initiates release; and a slow phase associated with extended stimulation of the neuron. Thyroid hormones are sequestered by nerve terminals and can produce changes in behaviour and mood. They may therefore be involved in modulating central synaptic transmission. We studied the effects of L-triiodothyronine (T3), L-thyroxine (T4), reverse T3 (rT3) and D-T3 on depolarization-induced uptake of 45Ca by synaptosomes from euthyroid and hypothyroid rats. T3, but not T4, rT3, or D-T3 significantly enhanced depolarization-induced 45Ca uptake at physiologically relevant (1 to 10 nmol/L) concentrations. The stimulatory effect of 10 nmol/L T3 on depolarization-induced uptake after 2 seconds (21%) was greater than after 5 (10%) or 30 (8%) seconds, indicating that T3 enhanced primarily the fast-phase process. There was no effect of T3 or other hormones tested on nondepolarization-induced 45Ca uptake. Preincubation of synaptosomes with T3 prior to depolarization did not enhance the effect of T3; in fact, preincubations of 30 seconds or more resulted in diminished T3 effects. Preincubation of synaptosomes for 15 seconds with D-T3 or the addition of D-T3 and T3 together reduced the effect of T3. We found no difference in the effect of T3 on 45Ca uptake by synaptosomes from euthyroid and hypothyroid rats. These results suggest a novel mechanism of action of thyroid hormones in the brain

Stoichiometry of H+ ejection during respiration-dependent accumulation of Ca2+ by rat liver mitochondria.

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Brand, M D; Chen, C H; Lehninger, A L

1976-02-25

We have investigated the energy-dependent uptake of Ca2+ by rat liver mitochondria with succinate as respiratory substrate with rotenone added to block NAD-linked electron transport. In the presence of 3-hydroxybutyric or other permeant monocarboxylic acids Ca2+ was taken up to extents approaching those seen in the presence of phosphate. The quantitative relationship between cation and anion uptake was determined from the slope of a plot of 3-hydroxybutyrate uptake against Ca2+ uptake, a method which allowed determination of the stoichiometry without requiring ambiguous corrections for early nonenergized or nonstoichiometric binding events. This procedure showed that 2 molecules of 3-hydroxtbutyrate were accumulated with each Ca2+ ion. Under these conditions close to 2 Ca2+ ions and 4 molecules of 3-hydroxybutyrate were accumulated per pair of electrons per energy-conserving site of the respiratory chain. Since 3-hydroxybutyrate must be protonated to pass the membrane as the undissociated free acid, it is concluded that 4 protons were ejected (and subsequently reabsorbed) per pair of electrons per energy-conserving site, in contrast to the value 2.0 postulated by the chemiosmotic hypothesis.

Follicle-stimulating hormone receptor-mediated uptake of 45Ca2+ by proteoliposomes and cultured rat sertoli cells: Evidence for involvement of voltage-activated and voltage-independent calcium channels

International Nuclear Information System (INIS)

Grasso, P.; Reichert, L.E. Jr.

1989-01-01

We have previously reported incorporation into liposomes of Triton X-100-solubilized FSH receptor-G-protein complexes derived from purified bovine calf testis membranes. In the present study we have used this model system to show that FSH induces flux of 45Ca2+ into such proteoliposomes in a hormone-specific concentration-dependent manner. FSH, inactivated by boiling, had no stimulatory effect on 45Ca2+ flux, nor did isolated alpha- or beta-subunits of FSH. Addition of GTP (or its analogs 5'-guanylylimidodiphosphate and guanosine-5'-O-[3-thiotriphosphate]) or sodium fluoride (in the presence or absence of GTP or its analogs) failed to induce 45Ca2+ flux into proteoliposomes, suggesting that the uptake of 45Ca2+ was receptor, and not G-protein, related. Voltage-independent (ruthenium red and gadolinium chloride) and voltage-activated (methyoxyverapamil and nifedipine) calcium channel-blocking agents reduced FSH-stimulated 45Ca2+ flux into proteoliposomes to control levels. FSH also induced uptake of 45Ca2+ by cultured rat Sertoli cells. Ruthenium red and gadolinium chloride had no effect on basal levels of 45Ca2+ uptake or estradiol secretion by cultured rat Sertoli cells, nor did methoxyverapamil or nifedipine. All four calcium channel blockers, however, were able to reduce FSH-induced 45Ca2+ uptake to basal levels and FSH-stimulated conversion of androstenedione to estradiol by up to 50%, indicating an involvement of Ca2+ in FSH-stimulated steroidogenesis. Our results suggest that the well documented changes in intracellular calcium levels consequent to FSH binding may be due, at least in part, to an influx of calcium through FSH receptor-regulated calcium channels

Effects of high-altitude environment on cognitive function and ultrastructure in CA1 region of hippocampus of rats after sleep deprivation

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Jiang-hua SI

2014-04-01

Full Text Available Objective To investigate the effects of high-altitude environment on cognitive function and ultrastructure in CA1 region of the hippocampus of Wistar rats in sleep deprivation (SD.  Methods SD was induced in Wistar rats by employing "flower pot" technique. Sixty-four rats were randomly divided into 2 groups: Lanzhou group (at an altitude of 1520 m and Kekexili group (at an altitude of 4767 m, and each group was further divided into 4 subgroups according to the time of SD (0, 1, 3 and 5 d. The behaviors of rats were studied by Morris water maze test at given time points. The ultrastructure of hippocampal neurons was observed by transmission electron microscope (TEM.  Results 1 Compared with Lanzhou group, rat behavior of Kekexili group presented excitement-irritation-suppression changes with the extension of SD time, but the extent was weakened gradually, and time of sleepiness increased obviously. 2 Compared with Lanzhou group, neurons in CA1 region of hippocampus showed enlarged cell body, disappeared nuclear membrane, shrunken nuclei and decreased organelle. End-feet of glia cells sticking to capillaries swelled and ruptured, and the typical synaptic structure disappeared. 3 Morris water maze test: as compared with Lanzhou group, the escape latency of Kekexili group prolonged (P < 0.05, for all, the ability of distance exploration increased (P < 0.05, for all, and the times across plot decreased (P < 0.05, for all in 1, 3 and 5 d of SD.  Conclusions High-altitude environment may significantly influence the cognitive function of rats in SD, and there was close correlation between the cognitive disorders and the changes in the ultrastructure of hippocampal CA1 region. doi: 10.3969/j.issn.1672-6731.2014.04.012

Oxalic acid decreases calcium absorption in rats

International Nuclear Information System (INIS)

Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

1987-01-01

Calcium absorption from salts and foods intrinsically labeled with 45 Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO 3 and CaCl 2 than from CaC 2 O 4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach

Effects of different components of Mao Dongqing's total flavonoids and total saponins on transient ischemic attack (TIA) model of rats.

Science.gov (United States)

Miao, Ming-San; Peng, Meng-Fan; Ma, Rui-Juan; Bai, Ming; Liu, Bao-Song

2018-03-01

Objective: To study the effects of the different components of the total flavonoids and total saponins from Mao Dongqing's active site on the rats of TIA model, determine the optimal reactive components ratio of Mao Dongqing on the rats of TIA. Methods: TIA rat model was induced by tail vein injection of tert butyl alcohol, the blank group was injected with the same amount of physiological saline, then behavioral score wasevaluated. Determination the level of glutamic acid in serum, the activity of Na+-K+-ATP enzyme, CA ++ -ATP enzyme and Mg ++ -ATP enzyme in Brain tissue, observe the changes of hippocampus in brain tissue, the comprehensive weight method was used to evaluate the efficacy of each component finally. Results: The contents of total flavonoids and total saponins in the active part of Mao Dongqing can significantly improve the pathological changes of brain tissue in rats, improve the activity of Na + -K + -ATP enzyme, Ca ++ -ATP enzyme and Mg ++ -ATP enzyme in the brain of rats, and reduce the level of glutamic acid in serum. The most significant of the contents was the ratio of 10:6. The different proportions of total flavonoids and total saponins in the active part of Mao Dongqing all has a better effect on the rats with TIA, and the ratio of 10:6 is the best active component for preventing and controlling TIA.

Decorporation of 241Am and 252Cf by Ca-DTPA from rat, Syrian and Chinese hamster

International Nuclear Information System (INIS)

Seidel, A.

1977-01-01

Retention and mobilization by Ca-DTPA of 241 Am and 252 Cf from rats, Syrian and Chinese hamsters are compared. Previous observations of a much longer residence time of actinides in hamsters liver than in rat liver are confirmed. Identical dose-effect functions were obtained for skeleton of rats and Syrian hamsters whereas 252 Cf removal from Chinese hamster skeleton was lower. The mobilization of 241 Am was lower than that of 252 Cf. With regard to species differences, qualitatively similar results were obtained for 241 Am as for 252 Cf. The results will be discussed with regard to the reduction by DTPA treatment of radiation risk in animal species with different biological half times of actinides in their livers. In this connection, attention will be paid to the usefulness of long-term DTPA treatment

Synthesis and characterization of nano-sized CaCO3 in purified diet

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Mulyaningsih, N. N.; Tresnasari, D. R.; Ramahwati, M. R.; Juwono, A. L.; Soejoko, D. S.; Astuti, D. A.

2017-07-01

The growth and development of animals depend strongly on the balanced nutrition in the diet. This research aims is to characterize the weight variations of nano-sized calcium carbonate (CaCO3) in purified diet that to be fed to animal model of rat. The nano-sized CaCO3 was prepared by milling the calcium carbonate particles for 20 hours at a rotation speed of 1000 rpm and resulting particle size in a range of 2-50 nm. Nano-sized CaCO3 added to purified diet to the four formulas that were identified as normal diet (N), deficiency calcium (DC), rich in calcium (RC), and poor calcium (PC) with containing in nano-sized CaCO3 much as 0.50 %, 0.00 %, 0.75 % and 0.25 % respectively. The nutritional content of the purified diet was proximate analyzed, it resulted as followed moisture, ash, fat, protein, crude fiber. The quantities of chemical element were analyzed by atomic absorption spectrometry (AAS), it resulted iron, magnesium, potassium and calcium. The results showed that N diet (Ca: 16,914.29 ppm) were suggested for healthy rats and RC diet (Ca: 33,696.13 ppm) for conditioned osteoporosis rats. The crystalline phases of the samples that were examined by X-ray diffraction showed that crystalline phase increased with the increasing concentration of CaCO3.

Distribution, expression and functional effects of small conductance Ca-activated potassium (SK) channels in rat myometrium.

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Noble, Karen; Floyd, Rachel; Shmygol, Andre; Shmygol, Anatoly; Mobasheri, A; Wray, Susan

2010-01-01

Calcium-activated potassium channels are important in a variety of smooth muscles, contributing to excitability and contractility. In the myometrium previous work has focussed on the large conductance channels (BK), and the role of small conductance channels (SK) has received scant attention, despite the finding that over-expression of an SK channel isoform (SK3) results in uterine dysfunction and delayed parturition. This study therefore characterises the expression of the three SK channel isoforms (SK1-3) in rat myometrium throughout pregnancy and investigates their effect on cytosolic [Ca] and force and compares this with that of BK channels. Consistent expression of all SK isoform transcripts and clear immunostaining of SK1-3 was found. Inhibition of SK1-3 channels (apamin, scyllatoxin) significantly inhibited outward current, caused membrane depolarisation and elicited action potentials in previously quiescent cells. Apamin or scyllatoxin increased the amplitude of [Ca] and force in spontaneously contracting myometrial strips throughout gestation. The functional effect of SK inhibition was larger than that of BK channel inhibition. Thus we show for the first time that SK1-3 channels are expressed and translated throughout pregnancy and contribute to outward current, regulate membrane potential and hence Ca signals in pregnant rat myometrium. They contribute more to quiescence that BK channels. 2009 Elsevier Ltd. All rights reserved.

Green tea supplementation produces better neuroprotective effects than red and black tea in Alzheimer-like rat model.

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Schimidt, Helen L; Garcia, Alexandre; Martins, Alexandre; Mello-Carpes, Pamela B; Carpes, Felipe P

2017-10-01

Green tea from Camellia sinensis plays a neuroprotective role in different neurodegenerative conditions, such as memory deficits in Alzheimer disease (AD). However, whether other teas from Camellia sinensis present similar neuroprotective effect still is not clear. Here we investigate effects of green, red and black tea supplementation on memory and hippocampus oxidative status in a rat model of Alzheimer-like disease (AD-like). Wistar male rats were supplemented with green, red or black tea during 8weeks before Aβ intra-hippocampal injection (2μL of Aβ-25-35, CA1 region). AD and sham rats were submitted to memory tests. After euthanasia, oxidative status in the bilateral hippocampus was quantified. Green and red teas avoid memory deficits in AD rats, but only green tea also avoids oxidative stress and damage in the hippocampus. Green tea was more effective for neuroprotection than red and black teas from the Camellia sinensis in the AD rat model. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of 1,25(OH)2 vitamin D3 and ionized Ca2+ on 45Ca uptake by primary cultures of aortic myocytes of spontaneously hypertensive and Wistar Kyoto normotensive rats

International Nuclear Information System (INIS)

Bukoski, R.D.; Xue, H.; McCarron, D.A.

1987-01-01

The effect of several regulators of whole animal Ca 2+ homeostasis on 45 Ca uptake by primary cultures of aortic myocytes isolated from spontaneously hypertensive (SHR) and normotensive Wistar Kyoto (WKY) rats was examined. Exposure of confluent cells to 1.0, 1.25 or 1.50 mM ionized Ca 2+ in serum-free medium for seven days resulted in increased 45 Ca uptake at the higher concentrations of Ca 2+ in cells of the SHR but not the WKY. 1,25 (OH)2 vitamin D3 (1 ng/ml) for 7 days caused enhanced influx in cells from both the SHR and WKY while parathyroid hormone (1-34) (1 ng/ml) was without effect. The data indicate that humoral factors that serve to regulate whole animal Ca 2+ homeostasis may also play a role in the regulation of Ca 2+ metabolism of the vascular smooth muscle cell

Implementation of near-infrared spectroscopy in a rat model of cardiac arrest and resuscitation

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Rodriguez, Juan G.; Xiao, Feng; Ferrara, Davon; Ewing, Jennifer; Zhang, Shu; Alexander, Steven; Battarbee, Harold

2002-07-01

Transient global cerebral ischemia accompanying cardiac arrest (CA) often leads to permanent brain damage with poor neurological outcome. The precise chain of events underlying the cerebral damage after CA is still not fully understood. Progress in this area may profit from the development of new non-invasive tools that provide real-time information on the vascular and cellular processes preceding the damage. One way to assess these processes is through near-IR spectroscopy, which has demonstrated the ability to quantify changes in blood volume, hemoglobin oxygenation, cytochrome oxidase redox state, and tissue water content. Here we report on the successful implementation of this form of spectroscopy in a rat model of asphyxial CA and resuscitation, under hypothermic and normothermic conditions. Preliminary results are shown that provide a new temporal insight into the cerebral circulation during CA and post-resuscitation.

Region-specific roles of the prelimbic cortex, the dorsal CA1, the ventral DG and ventral CA1 of the hippocampus in the fear return evoked by a sub-conditioning procedure in rats.

Science.gov (United States)

Fu, Juan; Xing, Xiaoli; Han, Mengfi; Xu, Na; Piao, Chengji; Zhang, Yue; Zheng, Xigeng

2016-02-01

The return of learned fear is an important issue in anxiety disorder research since an analogous process may contribute to long-term fear maintenance or clinical relapse. A number of studies demonstrate that mPFC and hippocampus are important in the modulation of post-extinction re-expression of fear memory. However, the region-specific role of these structures in the fear return evoked by a sub-threshold conditioning (SC) is not known. In the present experiments, we first examined specific roles of the prelimbic cortex (PL), the dorsal hippocampus (DH, the dorsal CA1 area in particular), the ventral hippocampus (the ventral dentate gyrus (vDG) and the ventral CA1 area in particular) in this fear return process. Then we examined the role of connections between PL and vCA1 with this behavioral approach. Rats were subjected to five tone-shock pairings (1.0-mA shock) to induce conditioned fear (freezing), followed by three fear extinction sessions (25 tone-alone trials each session). After a post-test for extinction memory, some rats were retrained with the SC procedure to reinstate tone-evoked freezing. Rat groups were injected with low doses of the GABAA agonist muscimol to selectively inactivate PL, DH, vDG, or vCA1 120 min before the fear return test. A disconnection paradigm with ipsilateral or contralateral muscimol injection of the PL and the vCA1 was used to examine the role of this pathway in the fear return. We found that transient inactivation of these areas significantly impaired fear return (freezing): inactivation of the prelimbic cortex blocked SC-evoked fear return in particular but did not influence fear expression in general; inactivation of the DH area impaired fear return, but had no effect on the extinction retrieval process; both ventral DG and ventral CA1 are required for the return of extinguished fear whereas only ventral DG is required for the extinction retrieval. These findings suggest that PL, DH, vDG, and vCA1 all contribute to the fear

Dietary fibers from mushroom sclerotia. 4. In vivo mineral absorption using ovariectomized rat model.

Science.gov (United States)

Wong, Ka-Hing; Katsumata, Shin-Ichi; Masuyama, Ritsuko; Uehara, Mariko; Suzuki, Kazuharu; Cheung, Peter C K

2006-03-08

The effect of three novel dietary fibers (DFs) prepared from mushroom sclerotia, namely, Pleurotus tuber-regium, Polyporus rhinocerus, and Wolfiporia cocos, on calcium and magnesium absorption was evaluated in ovariectomized (OVX) rats fed with sclerotial DF based and low Ca (0.3%) diets for 14 days. The animals in the W. cocos DF diet group possessed significantly (p cocos DF group were also significantly (p cocos DF could improve the overall Ca and Mg absorptions of the OVX rats fed a low Ca diet. The potential use of sclerotial DFs as a functional food ingredient for enhancing mineral absorption is also discussed.

Fusion-activated Ca(2+ entry: an "active zone" of elevated Ca(2+ during the postfusion stage of lamellar body exocytosis in rat type II pneumocytes.

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Pika Miklavc

2010-06-01

Full Text Available Ca(2+ is essential for vesicle fusion with the plasma membrane in virtually all types of regulated exocytoses. However, in contrast to the well-known effects of a high cytoplasmic Ca(2+ concentration ([Ca(2+](c in the prefusion phase, the occurrence and significance of Ca(2+ signals in the postfusion phase have not been described before.We studied isolated rat alveolar type II cells using previously developed imaging techniques. These cells release pulmonary surfactant, a complex of lipids and proteins, from secretory vesicles (lamellar bodies in an exceptionally slow, Ca(2+- and actin-dependent process. Measurements of fusion pore formation by darkfield scattered light intensity decrease or FM 1-43 fluorescence intensity increase were combined with analysis of [Ca(2+](c by ratiometric Fura-2 or Fluo-4 fluorescence measurements. We found that the majority of single lamellar body fusion events were followed by a transient (t(1/2 of decay = 3.2 s rise of localized [Ca(2+](c originating at the site of lamellar body fusion. [Ca(2+](c increase followed with a delay of approximately 0.2-0.5 s (method-dependent and in the majority of cases this signal propagated throughout the cell (at approximately 10 microm/s. Removal of Ca(2+ from, or addition of Ni(2+ to the extracellular solution, strongly inhibited these [Ca(2+](c transients, whereas Ca(2+ store depletion with thapsigargin had no effect. Actin-GFP fluorescence around fused LBs increased several seconds after the rise of [Ca(2+](c. Both effects were reduced by the non-specific Ca(2+ channel blocker SKF96365.Fusion-activated Ca(2+entry (FACE is a new mechanism that leads to [Ca(2+](c transients at the site of vesicle fusion. Substantial evidence from this and previous studies indicates that fusion-activated Ca(2+ entry enhances localized surfactant release from type II cells, but it may also play a role for compensatory endocytosis and other cellular functions.

Simultaneous recording of the field-EPSP as well as the population spike in the CA1 region in freely moving rats by using a fixed "double"-recording electrode.

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Scherf, Thomas; Frey, Julietta U; Frey, Sabine

2010-04-30

The recording of field potentials in freely moving rats is a very appropriate and commonly used method to describe changes in cellular mechanisms underlying synaptic plasticity. Recently, we introduced a method for the simultaneous recording of both the field-EPSP as well as the population spike in the dentate gyrus of freely moving rats. We used self-made "double"-recording electrodes, consisting of two wires straighten together with a constant distance between both tips. This method was now further developed to obtain stable long-term recordings of CA1 field potentials. Rats were chronically implanted with a bipolar recording electrode; one tip of which reached the stratum radiatum to record the field-EPSP, the other tip was lowered into the stratum pyramidale of the same neuron population to record the population spike by stimulation of the contralateral CA3 (cCA3). In such prepared rats, simultaneously recorded field-EPSP as well as the population spike where thus obtained from their places of generation in a very reliable manner. This kind of preparation allowed a better standardization of stimulation intensities between different animals and stable electrophysiological recordings of both CA1-potentials over a time period of at least 24h in freely behaving animals. Furthermore, primed burst stimulation of the cCA3 (a single biphasic priming pulse was followed by a burst of 10 pulses (frequency of 100 Hz) 190 ms later; pulse duration per half-wave: 0.1 ms) resulted in an early-LTP of both measured parameters, the field-EPSP and the population spike in the CA1 region of freely moving rats. Copyright 2010 Elsevier B.V. All rights reserved.

Altered myoplasmic Ca(2+) handling in rat fast-twitch skeletal muscle fibres during disuse atrophy.

Science.gov (United States)

Weiss, Norbert; Andrianjafiniony, Tina; Dupré-Aucouturier, Sylvie; Pouvreau, Sandrine; Desplanches, Dominique; Jacquemond, Vincent

2010-03-01

Calcium-dependent signalling pathways are believed to play an important role in skeletal muscle atrophy, but whether intracellular Ca(2+) homeostasis is affected in that situation remains obscure. We show here that there is a 20% atrophy of the fast-type flexor digitorum brevis (FDB) muscle in rats hind limb unloaded (HU) for 2 weeks, with no change in fibre type distribution. In voltage-clamp experiments, the amplitude of the slow Ca(2+) current was found similar in fibres from control and HU animals. In fibres loaded with the Ca(2+) dye indo-1, the value for the rate of [Ca(2+)] decay after the end of 5-100-ms-long voltage-clamp depolarisations from -80 to +10 mV was found to be 30-50% lower in fibres from HU animals. This effect was consistent with a reduced contribution of both saturable and non-saturable components of myoplasmic Ca(2+) removal. However, there was no change in the relative amount of parvalbumin, and type 1 sarco-endoplasmic reticulum Ca(2+)-ATPase was increased by a factor of three in the atrophied muscles. Confocal imaging of mitochondrial membrane potential showed that atrophied FDB fibres had significantly depolarized mitochondria as compared to control fibres. Depolarization of mitochondria in control fibres with carbonyl cyanide-p-trifluoromethoxyphenylhydrazone induced a slowing of the decay of [Ca(2+)] transients accompanied by an increase in resting [Ca(2+)] and a reduction of the peak amplitude of the transients. Overall results provide the first functional evidence for severely altered intracellular Ca(2+) removal capabilities in atrophied fast-type muscle fibres and highlight the possible contribution of reduced mitochondrial polarisation.

pH dependence of the isoproterenol-induced /sup 45/Ca net uptake into the ventricular myocardium of rats

Energy Technology Data Exchange (ETDEWEB)

Haag, R

1975-01-01

Infarction-like or disseminated myocardial necroses can be produced in rats by high doses of isoprotenerol which stimulates the decomposition of energy-rich phosphates to a maximum. The paper shows that acidoses of different genesis (peroral administration of NH/sub 4/Cl, artificial respiration with CO/sub 2/) induced experimentally can inhibit the isoproterenol-induced /sup 45/Ca net uptake and the production of necroses. The findings suggest that Ca/sup + +/ ions play a key role in the production of myocardial necroses which has not been recognized until now - that increased Ca/sup + +/ uptake into damaged myocardial fibres is a result or, at the most, an accompanying symptom of necrosis production - should therefore be discarded.

Depolarization-dependent sup 45 Ca uptake by synaptosomes of rat cerebral cortex is enhanced by L-triiodothyronine

Energy Technology Data Exchange (ETDEWEB)

Mason, G.A.; Walker, C.H.; Prange, A.J. Jr. (Univ. of North Carolina, Chapel Hill (USA))

1990-08-01

Depolarization-induced release of neurotransmitters and other secretions from nerve endings is triggered by the rapid entry of Ca++ through voltage-sensitive channels. Calcium entry is thought to occur in two distinct phases or processes: a fast-phase response to an action potential, which initiates release; and a slow phase associated with extended stimulation of the neuron. Thyroid hormones are sequestered by nerve terminals and can produce changes in behaviour and mood. They may therefore be involved in modulating central synaptic transmission. We studied the effects of L-triiodothyronine (T3), L-thyroxine (T4), reverse T3 (rT3) and D-T3 on depolarization-induced uptake of 45Ca by synaptosomes from euthyroid and hypothyroid rats. T3, but not T4, rT3, or D-T3 significantly enhanced depolarization-induced 45Ca uptake at physiologically relevant (1 to 10 nmol/L) concentrations. The stimulatory effect of 10 nmol/L T3 on depolarization-induced uptake after 2 seconds (21%) was greater than after 5 (10%) or 30 (8%) seconds, indicating that T3 enhanced primarily the fast-phase process. There was no effect of T3 or other hormones tested on nondepolarization-induced 45Ca uptake. Preincubation of synaptosomes with T3 prior to depolarization did not enhance the effect of T3; in fact, preincubations of 30 seconds or more resulted in diminished T3 effects. Preincubation of synaptosomes for 15 seconds with D-T3 or the addition of D-T3 and T3 together reduced the effect of T3. We found no difference in the effect of T3 on 45Ca uptake by synaptosomes from euthyroid and hypothyroid rats. These results suggest a novel mechanism of action of thyroid hormones in the brain.

Simulating Urban Growth Using a Random Forest-Cellular Automata (RF-CA Model

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Courage Kamusoko

2015-04-01

Full Text Available Sustainable urban planning and management require reliable land change models, which can be used to improve decision making. The objective of this study was to test a random forest-cellular automata (RF-CA model, which combines random forest (RF and cellular automata (CA models. The Kappa simulation (KSimulation, figure of merit, and components of agreement and disagreement statistics were used to validate the RF-CA model. Furthermore, the RF-CA model was compared with support vector machine cellular automata (SVM-CA and logistic regression cellular automata (LR-CA models. Results show that the RF-CA model outperformed the SVM-CA and LR-CA models. The RF-CA model had a Kappa simulation (KSimulation accuracy of 0.51 (with a figure of merit statistic of 47%, while SVM-CA and LR-CA models had a KSimulation accuracy of 0.39 and −0.22 (with figure of merit statistics of 39% and 6%, respectively. Generally, the RF-CA model was relatively accurate at allocating “non-built-up to built-up” changes as reflected by the correct “non-built-up to built-up” components of agreement of 15%. The performance of the RF-CA model was attributed to the relatively accurate RF transition potential maps. Therefore, this study highlights the potential of the RF-CA model for simulating urban growth.

The Role of the Two-Pore Domain Potassium Channel TREK-1 in the Therapeutic Effects of Escitalopram in a Rat Model of Poststroke Depression.

Science.gov (United States)

Lin, Dai-Hua; Zhang, Xiang-Rong; Ye, Dong-Qing; Xi, Guang-Jun; Hui, Jiao-Jie; Liu, Shan-Shan; Li, Lin-Jiang; Zhang, Zhi-Jun

2015-06-01

Poststroke depression (PSD) is one of the most common neuropsychiatric complications after stroke. TREK-1, a two-pore-domain potassium channel, has been implicated in the pathogenesis of stroke and depression. The aim of this study was to investigate whether TREK-1 plays a role in the therapeutic effects of the selective serotonin reuptake inhibitor (SSRI) escitalopram in a rat PSD model. The whole-cell patch-clamp technique was performed to assess the effect of escitalopram on recombinant TREK-1 currents in HEK293 cells. The expression of TREK-1 mRNA and protein was measured in the hippocampus and prefrontal cortex (PFC), and neural stem cell (NSC) proliferation was detected in the hippocampal dentate gyrus (DG) in PSD rats after 3 weeks of escitalopram administration. Escitalopram reversibly inhibited TREK-1 currents in a concentration-dependent manner. Chronic treatment with escitalopram significantly reversed the reductions in weight gain, locomotor activity, and sucrose preference in PSD rats. The expressions of TREK-1 mRNA and protein were significantly increased in hippocampal CA1, CA3, DG, and PFC in PSD rats, with the exception of TREK-1 mRNA in hippocampal CA1. NSC proliferation was significantly decreased in hippocampal DG of PSD rats. Escitalopram significantly reversed the regional increases of TREK-1 expression and the reduction of hippocampal NSC proliferation in PSD rats. TREK-1 plays an important role in the therapeutic effects of the SSRI escitalopram in PSD model, making TREK-1 an attractive candidate molecule for further understanding the pathophysiology and treatment of PSD. © 2015 John Wiley & Sons Ltd.

Oxidative stress evoked damages leading to attenuated memory and inhibition of NMDAR-CaMKII-ERK/CREB signalling on consumption of aspartame in rat model.

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Iyaswamy, Ashok; Kammella, Ananth Kumar; Thavasimuthu, Citarasu; Wankupar, Wankhar; Dapkupar, Wankhar; Shanmugam, Sambantham; Rajan, Ravindran; Rathinasamy, Sheeladevi

2018-04-01

Many controversial reports are available on the use of aspartame as it releases methanol as one of its metabolite during metabolism. The present study proposes to investigate whether long term (90 days) aspartame (40 mg/kg b.wt) administration could induce oxidative stress and alter the memory in Wistar strain male albino rats. To mimic the human methanol metabolism, methotrexate (MTX)-treated rats were included as a model to study the effects of aspartame. Wistar strain albino rats were administered with aspartame (40 mg/kg b.wt) orally and studied along with controls and MTX-treated controls. Aspartame interfered in the body weight and corticosterone levels in the rats. A marked increase in the mRNA and protein expression of neuronal nitric oxide synthase (nNOS) and induced nitric oxide synthase (iNOS) which resulted in the increased nitric oxide radical's level indicating that aspartame is a stressor. These reactive nitrogen species could be responsible for the altered cell membrane integrity and even cause death of neurons by necrosis or apoptosis. The animals showed a marked decrease in learning, spatial working and spatial recognition memory deficit in the Morris water maze and Y-maze performance task which could have resulted due to reduced hippocampal acetylcholine esterase (AChE) activity. The animal brain homogenate also revealed the decrease in the phosphorylation of NMDAR1-CaMKII-ERK/CREB signalling pathway, which well documents the inhibition of phosphorylation leads to the excitotoxicity of the neurons and memory decline. This effect may be due to methanol which may also activate the NOS levels, microglia and astrocytes, inducing neurodegeneration in brain. Neuronal shrinkage of hippocampal layer due to degeneration of pyramidal cells revealed the abnormal neuronal morphology of pyramidal cell layers in the aspartame treated animals. These findings demonstrate that aspartame metabolites could be a contributing factor for the development of oxidative

How Does the Ca2+-paradox Injury Induce Contracture in the Heart?—A Combined Study of the Intracellular Ca2+ Dynamics and Cell Structures in Perfused Rat Hearts—

International Nuclear Information System (INIS)

Mani, Hiroki; Tanaka, Hideo; Adachi, Tetsuya; Ikegawa, Masaya; Dai, Ping; Fujita, Naohisa; Takamatsu, Tetsuro

2015-01-01

The calcium (Ca 2+ )-paradox injury of the heart, induced by restoration of extracellular Ca 2+ after its short-term depletion, is known to provoke cardiomyocyte contracture. However, undetermined is how the Ca 2+ -paradox provokes such a distinctive presentation of myocytes in the heart. To address this, we imaged sequential intracellular Ca 2+ dynamics and concomitant structures of the subepicardial ventricular myocytes in fluo3-loaded, Langendorff-perfused rat hearts produced by the Ca 2+ paradox. Under rapid-scanning confocal microscopy, repletion of Ca 2+ following its depletion produced high-frequency Ca 2+ waves in individual myocytes with asynchronous localized contractions, resulting in contracture within 10 min. Such alterations of myocytes were attenuated by 5-mM NiCl 2 , but not by verapamil, SEA0400, or combination of ryanodine and thapsigargin, indicating a contribution of non-specific transmembrane Ca 2+ influx in the injury. However, saponin-induced membrane permeabilization of Ca 2+ showed no apparent contracture despite the emergence of high-frequency Ca 2+ waves, indicating an essential role of myocyte-myocyte and myocyte-extracellular matrix (ECM) mechanical connections in the Ca 2+ paradox. In immunohistochemistry Ca 2+ depletion produced separation of the intercalated disc that expresses cadherin and dissipation of β-dystroglycan located along the sarcolemma. Taken together, along with the trans-sarcolemmal Ca 2+ influx, disruption of cell-cell and cell-ECM connections is essential for contracture in the Ca 2+ -paradox injury

Conducted vasoconstriction in rat mesenteric arterioles: role for dihydropyridine-insensitive Ca(2+) channels

DEFF Research Database (Denmark)

Gustafsson, F; Andreasen, D; Salomonsson, Max

2001-01-01

The aim of this study was to evaluate the role of voltage-operated Ca(2+) channels in the initiation and conduction of vasoconstrictor responses to local micropipette electrical stimulation of rat mesenteric arterioles (28 +/- 1 microm, n = 79) in vivo. Local and conducted (600 microm upstream from...... the pipette) vasoconstriction was not blocked by TTX (1 micromol/l, n = 5), nifedipine, or nimodipine (10 micromol/l, n = 9). Increasing the K(+) concentration of the superfusate to 75 mmol/l did not evoke vasoconstriction, but this depolarizing stimulus reversibly abolished vasoconstrictor responses...

Effects of unpredictable chronic stress on behavior and brain-derived neurotrophic factor expression in CA3 subfield and dentate gyrus of the hippocampus in different aged rats.

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Li, Ying; Ji, Yong-juan; Jiang, Hong; Liu, De-xiang; Zhang, Qian; Fan, Shu-jian; Pan, Fang

2009-07-05

Brain-derived neurotrophic factor (BDNF) is a stress-responsive intercellular messenger modifying hypothalamic-pituitary-adrenal (HPA) axis activity. The interaction between stress and age in BDNF expression is currently not fully understood. This study was conducted to observe unpredictable stress effect on behavior and BDNF expression in CA3 subfield (CA3) and dentate gyrus of hippocampus in different aged rats. Forty-eight Wistar rats of two different ages (2 months and 15 months) were randomly assigned to six groups: two control groups and four stress groups. The rats in the stress group received three weeks of unpredictable mild stress. The depression state and the stress level of the animals were determined by sucrose preference test and observation of exploratory behavior in an open field (OF) test. The expressions of BDNF in CA3 and dentate gyrus of the hippocampus were measured using immunohistochemistry. Age and stress had different effects on the behavior of different aged animals (age: F = 6.173, P BDNF expression in the CA3 and dentate gyrus regions of the hippocampus following stress in both age groups (P BDNF (F = 9.408, P BDNF expression compared to the young stressed group at every testing time point. Stress has age-dependent effects on behavioral responses and hippocampal BDNF expression in rats.

Cyclic ADP ribose-dependent Ca2+ release by group I metabotropic glutamate receptors in acutely dissociated rat hippocampal neurons.

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Jong-Woo Sohn

Full Text Available Group I metabotropic glutamate receptors (group I mGluRs; mGluR1 and mGluR5 exert diverse effects on neuronal and synaptic functions, many of which are regulated by intracellular Ca(2+. In this study, we characterized the cellular mechanisms underlying Ca(2+ mobilization induced by (RS-3,5-dihydroxyphenylglycine (DHPG; a specific group I mGluR agonist in the somata of acutely dissociated rat hippocampal neurons using microfluorometry. We found that DHPG activates mGluR5 to mobilize intracellular Ca(2+ from ryanodine-sensitive stores via cyclic adenosine diphosphate ribose (cADPR, while the PLC/IP(3 signaling pathway was not involved in Ca(2+ mobilization. The application of glutamate, which depolarized the membrane potential by 28.5±4.9 mV (n = 4, led to transient Ca(2+ mobilization by mGluR5 and Ca(2+ influx through L-type Ca(2+ channels. We found no evidence that mGluR5-mediated Ca(2+ release and Ca(2+ influx through L-type Ca(2+ channels interact to generate supralinear Ca(2+ transients. Our study provides novel insights into the mechanisms of intracellular Ca(2+ mobilization by mGluR5 in the somata of hippocampal neurons.

MORPHOLOGICAL CHANGES IN THE HIPPOCAMPUS OF RATS IN ACCELERATED AGING

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K. Yu. Maksimova

2014-01-01

Full Text Available The aim of this work was the analysis of structural changes with age in the hippocampus of senescenceaccelerated OXYS rats when signs of accelerated brain aging are missing (age 14 days, developments (age 5 months, and active progresses (age 15 months. The study was performed on 15 OXYS rats and 15 Wistar rats (as a control. After dislocation, brains were dissected, fixed with 10% formalin, embedded in paraffin, and serially cut in coronal sections (5μm thickness. These sections were stained with Cresyl violet and examined with a photomicroscope (Carl Zeiss Axiostar plus, Germany. The total number of hippocampal pyramidal cells in the CA1, CA3 and the dentate gyrus regions were estimated in 14-dayold, 5and 15-month-old OXYS and Wistar rats (n = 5 on the 5 slices of each brain sections. The number of neurons with chromatolysis, hyperchromatic with darkly stained cytoplasm and shrunken neurons were calculated as degenerative neurons. The pictures obtained with the program Carl Zeiss Axio Vision 8.0 with increasing 10  100, determined the average area bodies and nuclei of neurons (mkm2. The significant structural changes of neurons in the CA1, CA3 and dentate gyrus regions of the hippocampus in OXYS rats at 5 month of age are revealed by light microscopy. This results indicates the early develop neurodegeneration in OXYS rats. The most pronounced morphological changes occur in the CA1 region of the hippocampus of OXYS rats and irreversible. The degenerative changes of neurons in the hippocampus increases by the age of 15 months. Morphometric analysis of the average area of bodies and the nuclei of hippocampal neurons in CA1, CA3 and the dentate gyrus regions of OXYS and Wistar rats at 14 days of age showed no significant interline differences. At 5 months of age in the CA1 region of the hippocampus of OXYS rats was determined a significantly lower average body size and nuclei of pyramidal neurons compared with Wistar rats. With age, these

CXL-1020, a Novel Nitroxyl (HNO Prodrug, Is More Effective than Milrinone in Models of Diastolic Dysfunction—A Cardiovascular Therapeutic: An Efficacy and Safety Study in the Rat

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Steve R. Roof

2017-11-01

Full Text Available The nitroxyl (HNO prodrug, CXL-1020, induces vasorelaxation and improves cardiac function in canine models and patients with systolic heart failure (HF. HNO's unique mechanism of action may be applicable to a broader subset of cardiac patients. This study investigated the load-independent safety and efficacy of CXL-1020 in two rodent (rat models of diastolic heart failure and explored potential drug interactions with common HF background therapies. In vivo left-ventricular hemodynamics/pressure-volume relationships assessed before/during a 30 min IV infusion of CXL-1020 demonstrated acute load-independent positive inotropic, lusitropic, and vasodilatory effects in normal rats. In rats with only diastolic dysfunction due to bilateral renal wrapping (RW or pronounced diastolic and mild systolic dysfunction due to 4 weeks of chronic isoproterenol exposure (ISO, CXL-1020 attenuated the elevated LV filling pressures, improved the end diastolic pressure volume relationship, and accelerated relaxation. CXL-1020 facilitated Ca2+ re-uptake and enhanced myocyte relaxation in isolated cardiomyocytes from ISO rats. Compared to milrinone, CXL-1020 more effectively improved Ca2+ reuptake in ISO rats without concomitant chronotropy, and did not enhance Ca2+ entry via L-type Ca2+ channels nor increase myocardial arrhythmias/ectopic activity. Acute-therapy with CXL-1020 improved ventricular relaxation and Ca2+ cycling, in the setting of chronic induced diastolic dysfunction. CXL-1020's lusitropic effects were greater than those seen with the cAMP-dependent agent milrinone, and unlike milrinone it did not produce chronotropy or increased ectopy. HNO is a promising new potential therapy for both systolic and diastolic heart failure.

Prenatal nicotine and maternal deprivation stress de-regulate the development of CA1, CA3, and dentate gyrus neurons in hippocampus of infant rats.

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Hong Wang

Full Text Available Adverse experiences by the developing fetus and in early childhood are associated with profound effects on learning, emotional behavior, and cognition as a whole. In this study we investigated the effects of prenatal nicotine exposure (NIC, postnatal maternal deprivation (MD or the combination of the two (NIC+MD to determine if hippocampal neuron development is modulated by exposure to drugs of abuse and/or stress. Growth of rat offspring exposed to MD alone or NIC+MD was repressed until after weaning. In CA1 but not CA3 of postnatal day 14 (P14 pups, MD increased pyramidal neurons, however, in dentate gyrus (DG, decreased granule neurons. NIC had no effect on neuron number in CA1, CA3 or DG. Unexpectedly, NIC plus MD combined caused a synergistic increase in the number of CA1 or CA3 neurons. Neuron density in CA regions was unaffected by treatment, but in the DG, granule neurons had a looser packing density after NIC, MD or NIC+MD exposure. When septotemporal axes were analyzed, the synergism of stress and drug exposure in CA1 and CA3 was associated with rostral, whereas MD effects were predominantly associated with caudal neurons. TUNEL labeling suggests no active apoptosis at P14, and doublecortin positive neurons and mossy fibers were diminished in NIC+MD relative to controls. The laterality of the effect of nicotine and/or maternal deprivation in right versus left hippocampus was also analyzed and found to be insiginificant. We report for the first time that early life stressors such as postnatal MD and prenatal NIC exposure, when combined, may exhibit synergistic consequences for CA1 and CA3 pyramidal neuron development, and a potential antagonistic influence on developing DG neurons. These results suggest that early stressors may modulate neurogenesis, apoptosis, or maturation of glutamatergic neurons in the hippocampus in a region-specific manner during critical periods of neurodevelopment.

Edaravone improves survival and neurological outcomes after CPR in a ventricular fibrillation model of rats.

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Qin, Tao; Lei, Ling-Yan; Li, Nuo; Shi, Fangying Ruan; Chen, Meng-Hua; Xie, Lu

2016-10-01

Overproduction of free radicals is a main factor contributing to cerebral injury after cardiac arrest (CA)/cardiopulmonary resuscitation (CPR). We sought to evaluate the impact of edaravone on the survival and neurological outcomes after CA/CPR in rats. Rats were subjected to CA following CPR. For survival study, the rats with restoration of spontaneous circulation (ROSC) were randomly allocated to one of the two groups (edaravone and saline group, n=20/each group) to received Edaravone (3 mg/kg) or normal saline. Another 10 rats without experiencing CA and CPR served as the sham group. Survival was observed for 72 hours and the neurological deficit score (NDS) was calculated at 12, 24, 48, and 72 hours after ROSC. For the neurological biochemical analysis study, rats were subjected to the same experimental procedures. Then, edaravone group (n=24), saline group (n=24) and sham group (n=16) were further divided into 4 subgroups according to the different time intervals (12, 24, 48, and 72 hours following ROSC). Brain tissues were harvested at relative time intervals for evaluation of oxidative stress, TUNEL staining and apoptotic gene expression. Edaravone improved postresuscitative survival time and neurological deficit, decreased brain malonylaldehyde level, increased superoxide dismutase activities, decreased proapoptotic gene expression of capase-8, capase-3, and Bax, and increased antiapoptotic Bcl-2 expression at 12, 24, 48, and 72 hours after ROSC. Edaravone improves survival and neurological outcomes following CPR via antioxidative and antiapoptotic effects in rats. Copyright © 2016 Elsevier Inc. All rights reserved.

Preictal activity of subicular, CA1, and dentate gyrus principal neurons in the dorsal hippocampus before spontaneous seizures in a rat model of temporal lobe epilepsy.

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Fujita, Satoshi; Toyoda, Izumi; Thamattoor, Ajoy K; Buckmaster, Paul S

2014-12-10

Previous studies suggest that spontaneous seizures in patients with temporal lobe epilepsy might be preceded by increased action potential firing of hippocampal neurons. Preictal activity is potentially important because it might provide new opportunities for predicting when a seizure is about to occur and insight into how spontaneous seizures are generated. We evaluated local field potentials and unit activity of single, putative excitatory neurons in the subiculum, CA1, CA3, and dentate gyrus of the dorsal hippocampus in epileptic pilocarpine-treated rats as they experienced spontaneous seizures. Average action potential firing rates of neurons in the subiculum, CA1, and dentate gyrus, but not CA3, increased significantly and progressively beginning 2-4 min before locally recorded spontaneous seizures. In the subiculum, CA1, and dentate gyrus, but not CA3, 41-57% of neurons displayed increased preictal activity with significant consistency across multiple seizures. Much of the increased preictal firing of neurons in the subiculum and CA1 correlated with preictal theta activity, whereas preictal firing of neurons in the dentate gyrus was independent of theta. In addition, some CA1 and dentate gyrus neurons displayed reduced firing rates preictally. These results reveal that different hippocampal subregions exhibit differences in the extent and potential underlying mechanisms of preictal activity. The finding of robust and significantly consistent preictal activity of subicular, CA1, and dentate neurons in the dorsal hippocampus, despite the likelihood that many seizures initiated in other brain regions, suggests the existence of a broader neuronal network whose activity changes minutes before spontaneous seizures initiate. Copyright © 2014 the authors 0270-6474/14/3416671-17$15.00/0.

Hydroxyhydroquinone, a by-product of coffee bean roasting, increases intracellular Ca2+ concentration in rat thymic lymphocytes.

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Kamae, Risa; Nojima, Shoko; Akiyoshi, Kenji; Setsu, Shoki; Honda, Sari; Masuda, Toshiya; Oyama, Yasuo

2017-04-01

Hydroxyhydroquinone (HHQ) is generated during coffee bean roasting. A cup of coffee contains 0.1-1.7 mg of HHQ. The actions of HHQ on mammalian DNA were examined because HHQ is a metabolite of benzene, which causes leukemia. Currently, information on the cellular actions of HHQ is limited. We examined the effects of sublethal levels of HHQ on the concentration of intracellular Ca 2+ in rat thymic lymphocytes by using a flow cytometric technique with fluorescent probes. HHQ at 10 μM or more significantly elevated intracellular Ca 2+ levels by increasing the membrane permeability of divalent cations, resulting in hyperpolarization via the activation of Ca 2+ -dependent K + channels. HHQ-induced changes in the intracellular Ca 2+ concentration and membrane potential may affect the cell functions of lymphocytes. HHQ-reduced coffee may be preferable in order to avoid the possible adverse effects of HHQ. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ventral tegmental area disruption selectively affects CA1/CA2 but not CA3 place fields during a differential reward working memory task.

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Martig, Adria K; Mizumori, Sheri J Y

2011-02-01

Hippocampus (HPC) receives dopaminergic (DA) projections from the ventral tegmental area (VTA) and substantia nigra. These inputs appear to provide a modulatory signal that influences HPC dependent behaviors and place fields. We examined how efferent projections from VTA to HPC influence spatial working memory and place fields when the reward context changes. CA1 and CA3 process environmental context changes differently and VTA preferentially innervates CA1. Given these anatomical data and electrophysiological evidence that implicate DA in reward processing, we predicted that CA1 place fields would respond more strongly to both VTA disruption and changes in the reward context than CA3 place fields. Rats (N = 9) were implanted with infusion cannula targeting VTA and recording tetrodes aimed at HPC. Then they were tested on a differential reward, win-shift working memory task. One recording session consisted of 5 baseline and 5 manipulation trials during which place cells in CA1/CA2 (N = 167) and CA3 (N = 94) were recorded. Prior to manipulation trials rats were infused with either baclofen or saline and then subjected to control or reward conditions during which the learned locations of large and small reward quantities were reversed. VTA disruption resulted in an increase in errors, and in CA1/CA2 place field reorganization. There were no changes in any measures of CA3 place field stability during VTA disruption. Reward manipulations did not affect performance or place field stability in CA1/CA2 or CA3; however, changes in the reward locations "rescued" performance and place field stability in CA1/CA2 when VTA activity was compromised, perhaps by trigging compensatory mechanisms. These data support the hypothesis that VTA contributes to spatial working memory performance perhaps by maintaining place field stability selectively in CA1/CA2. Copyright © 2009 Wiley-Liss, Inc.

Intrastriatal injections of KN-93 ameliorates levodopa-induced dyskinesia in a rat model of Parkinson’s disease

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Yang X

2013-08-01

Full Text Available Xinxin Yang, Na Wu, Lu Song, Zhenguo Liu Department of Neurology, Xinhua Hospital affiliated with Shanghai Jiao Tong University School of Medicine, Shanghai, People’s Republic of China Background: Levodopa remains the most effective drug for the treatment of Parkinson’s disease (PD. However, long-term levodopa treatment is associated with the emergence of levodopa-induced dyskinesia (LID, which has hampered its use for PD treatment. The mechanisms of LID are only partially understood. A previous study showed that KN-93, a Ca2+/calmodulin-dependent protein kinase II (CaMKII inhibitor, could be used to ameliorate LID in rats. However, the precise mechanisms by which KN-93 acts as an antidyskinetic are not fully understood. Methods: In the present study, a rat model of PD was induced by 6-hydroxydopamine (OHDA injections. Then, the successfully lesioned rats were intrastriatally administered with a different dose of KN-93 (1 µg, 2 µg, or 5 µg prior to levodopa treatment. Abnormal involuntary movements (AIMs scores and apomorphine-induced rotations were measured in PD rats. Phosphorylated levels of GluR1 at Serine-845 (pGluR1S845 levels were determined by western blot. Arc and Penk levels were measured by real-time polymerase chain reaction (PCR. Results: We found that both 2 µg and 5 µg KN-93 treatment lowered AIMs scores in levodopa priming PD rats without affecting the antiparkinsonian effect of levodopa. In agreement with behavioral analysis, KN-93 treatment (2 µg reduced pGluR1S845 levels in PD rats. Moreover, KN-93 treatment (2 µg reduced the expression of Gad1 and Nur77 in PD rats. Conclusion: These data indicated that intrastriatal injections of KN-93 were beneficial in reducing the expression of LID by lowering the expression of pGluR1S845 via suppressing the activation of CaMKII in PD rats. Decreased expression of pGluR1S845 further reduced the expression of Gad1 and Nur77 in PD rats. Keywords: Parkinson’s disease, levodopa

Effect of short-term ornithine alpha-ketoglutarate pretreatment on intestinal ischemia-reperfusion in rats

OpenAIRE

Gonçalves,Eduardo Silvio Gouveia; Rabelo,Camila Menezes; Prado Neto,Alberico Ximenes do; Garcia,José Huygens Parente; Guimarães,Sérgio Botelho; Vasconcelos,Paulo Roberto Leitão de

2011-01-01

PURPOSE: To investigate the effects of preventive enteral administration of ornithine alpha-ketoglutarate (OKG) in an ischemia-reperfusion rat model. METHODS: Sixty rats were randomized into five groups (G1-G5, n = 12). Each group was divided into two subgroups (n = 6) and treated with calcium carbonate (CaCa) or OKG by gavage. Thirty minutes later, the animals were anesthetized with xylazine 15mg + ketamine 1mg ip and subjected to laparotomy. G1-G3 rats served as controls. Rats in groups G4 ...

Stereological brain volume changes in post-weaned socially isolated rats

DEFF Research Database (Denmark)

Fabricius, Katrine; Helboe, Lone; Steiniger-Brach, Björn

2010-01-01

Rearing rats in isolation after weaning is an environmental manipulation that leads to behavioural and neurochemical alterations that resemble what is seen in schizophrenia. The model is neurodevelopmental in origin and has been used as an animal model of schizophrenia. However, only a few studies...... Lister Hooded rats isolated from postnatal day 25 for 15 weeks. We observed the expected gender differences in total brain volume with males having larger brains than females. Further, we found that isolated males had significantly smaller brains than group-housed controls and larger lateral ventricles...... than controls. However, this was not seen in female rats. Isolated males had a significant smaller hippocampus, dentate gyrus and CA2/3 where isolated females had a significant smaller CA1 compared to controls. Thus, our results indicate that long-term isolation of male rats leads to neuroanatomical...

Numerical model of Ca(OH)

NARCIS (Netherlands)

Koster, T.; Peelen, W.; Larbi, J.; Rooij, M. de; Polder, R.

2010-01-01

A mathematical model is being developed to describe a repair method in concrete, called cathodic protection (CP). The model is in principle also useful to describe electrodeposition in concrete, e.g. the process of re-precipitation of Ca(OH)₂ invoked by an electrical current. In CP, the

K(Ca)3.1 channel downregulation and impaired endothelium-derived hyperpolarization-type relaxation in pulmonary arteries from chronically hypoxic rats

DEFF Research Database (Denmark)

Kroigaard, Christel; Kudryavtseva, Olga; Dalsgaard, Thomas

2013-01-01

hypoxia-induced pulmonary hypertension in rats. For functional studies, pulmonary arteries were mounted in microvascular myographs for isometric tension recordings. The K(Ca) channel expression was evaluated by immunoblotting and quantitative PCR. Although ACh induced similar relaxations, the ACh...

Epigenetic Methylation of Parathyroid CaR and VDR Promoters in Experimental Secondary Hyperparathyroidism

DEFF Research Database (Denmark)

Hofman-Bang, Jacob; Gravesen, Eva; Olgaard, Klaus

2012-01-01

R in parathyroid cultures decreases rapidly. Methylation of promoter regions is often detected during epigenetic downregulation of gene expression. Therefore, using an experimental rat model, we examined changes in methylation levels of parathyroid CaR and VDR promoters in vivo and in vitro. Methods. Uremia...... of parathyroid CaR and VDR genes were found. Thus, epigenetic methylation of these promoters does not explain decreased parathyroid expression of CaR and VDR genes in uremic s-HPT....

Aging Enables Ca2+ Overload and Apoptosis Induced by Amyloid-β Oligomers in Rat Hippocampal Neurons: Neuroprotection by Non-Steroidal Anti-Inflammatory Drugs and R-Flurbiprofen in Aging Neurons.

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Calvo-Rodríguez, María; García-Durillo, Mónica; Villalobos, Carlos; Núñez, Lucía

2016-07-22

The most important risk factor for Alzheimer's disease (AD) is aging. Neurotoxicity in AD has been linked to dyshomeostasis of intracellular Ca2+ induced by small aggregates of the amyloid-β peptide 1-42 (Aβ42 oligomers). However, how aging influences susceptibility to neurotoxicity induced by Aβ42 oligomers is unknown. In this study, we used long-term cultures of rat hippocampal neurons, a model of neuronal in vitro aging, to investigate the contribution of aging to Ca2+ dishomeostasis and neuron cell death induced by Aβ42 oligomers. In addition, we tested whether non-steroidal anti-inflammatory drugs (NSAIDs) and R-flurbiprofen prevent apoptosis acting on subcellular Ca2+ in aged neurons. We found that Aβ42 oligomers have no effect on young hippocampal neurons cultured for 2 days in vitro (2 DIV). However, they promoted apoptosis modestly in mature neurons (8 DIV) and these effects increased dramatically after 13 DIV, when neurons display many hallmarks of in vivo aging. Consistently, cytosolic and mitochondrial Ca2+ responses induced by Aβ42 oligomers increased dramatically with culture age. At low concentrations, NSAIDs and the enantiomer R-flurbiprofen lacking anti-inflammatory activity prevent Ca2+ overload and neuron cell death induced by Aβ42 oligomers in aged neurons. However, at high concentrations R-flurbiprofen induces apoptosis. Thus, Aβ42 oligomers promote Ca2+ overload and neuron cell death only in aged rat hippocampal neurons. These effects are prevented by low concentrations of NSAIDs and R-flurbiprofen acting on mitochondrial Ca2+ overload.

Na(+)/Ca(2+) exchanger inhibition exerts a positive inotropic effect in the rat heart, but fails to influence the contractility of the rabbit heart.

Science.gov (United States)

Farkas, A S; Acsai, K; Nagy, N; Tóth, A; Fülöp, F; Seprényi, G; Birinyi, P; Nánási, P P; Forster, T; Csanády, M; Papp, J G; Varró, A; Farkas, A

2008-05-01

The Na(+)/Ca(2+) exchanger (NCX) may play a key role in myocardial contractility. The operation of the NCX is affected by the action potential (AP) configuration and the intracellular Na(+) concentration. This study examined the effect of selective NCX inhibition by 0.1, 0.3 and 1.0 microM SEA0400 on the myocardial contractility in the setting of different AP configurations and different intracellular Na(+) concentrations in rabbit and rat hearts. The concentration-dependent effects of SEA0400 on I(Na/Ca) were studied in rat and rabbit ventricular cardiomyocytes using a patch clamp technique. Starling curves were constructed for isolated, Langendorff-perfused rat and rabbit hearts. The cardiac sarcolemmal NCX protein densities of both species were compared by immunohistochemistry. SEA0400 inhibited I(Na/Ca) with similar efficacy in the two species; there was no difference between the inhibitions of the forward or reverse mode of the NCX in either species. SEA0400 increased the systolic and the developed pressure in the rat heart in a concentration-dependent manner, for example, 1.0 microM SEA0400 increased the maximum systolic pressures by 12% relative to the control, whereas it failed to alter the contractility in the rabbit heart. No interspecies difference was found in the cardiac sarcolemmal NCX protein densities. NCX inhibition exerted a positive inotropic effect in the rat heart, but it did not influence the contractility of the rabbit heart. This implies that the AP configuration and the intracellular Na(+) concentration may play an important role in the contractility response to NCX inhibition.

Ursodeoxycholic and deoxycholic acids: Differential effects on intestinal Ca(2+) uptake, apoptosis and autophagy of rat intestine.

Science.gov (United States)

Rodríguez, Valeria A; Rivoira, María A; Pérez, Adriana del V; Marchionatti, Ana M; Tolosa de Talamoni, Nori G

2016-02-01

The aim of this work was to study the effect of sodium deoxycholate (NaDOC) and ursodeoxycholic acid (UDCA) on Ca(2+) uptake by enterocytes and the underlying mechanisms. Rats were divided into four groups: a) controls, b) treated with NaDOC, c) treated with UDCA d) treated with NaDOC and UDCA. Ca(2+) uptake was studied in enterocytes with different degrees of maturation. Apoptosis, autophagy and NO content and iNOS protein expression were evaluated. NaDOC decreased and UDCA increased Ca(2+) uptake only in mature enterocytes. The enhancement of protein expression of Fas, FasL, caspase-8 and caspase-3 activity by NaDOC indicates triggering of the apoptotic extrinsic pathway, which was blocked by UDCA. NO content and iNOS protein expression were enhanced by NaDOC, and avoided by UDCA. The increment of acidic vesicular organelles and LC3 II produced by NaDOC was also prevented by UDCA. In conclusion, the inhibitory effects of NaDOC on intestinal Ca(2+) absorption occur by decreasing the Ca(2+) uptake by mature enterocytes. NaDOC triggers apoptosis and autophagy, in part as a result of nitrosative stress. In contrast, UDCA increases the Ca(2+) uptake by mature enterocytes, and in combination with NaDOC acts as an antiapoptotic and antiautophagic agent normalizing the transcellular Ca(2+) pathway. Copyright © 2015 Elsevier Inc. All rights reserved.

The Role of Ca2+ and BK Channels of Locus Coeruleus (LC) Neurons as a Brake to the CO2 Chemosensitivity Response of Rats.

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Imber, Ann N; Patrone, Luis G A; Li, Ke-Yong; Gargaglioni, Luciane H; Putnam, Robert W

2018-06-15

The cellular mechanisms by which LC neurons respond to hypercapnia are usually attributed to an "accelerator" whereby hypercapnic acidosis causes an inhibition of K + channels or activation of Na + and Ca +2 channels to depolarize CO 2 -sensitive neurons. Nevertheless, it is still unknown if this "accelerator" mechanism could be controlled by a brake phenomenon. Whole-cell patch clamping, fluorescence imaging microscopy and plethysmography were used to study the chemosensitive response of the LC neurons. Hypercapnic acidosis activates L-type Ca 2+ channels and large conductance Ca-activated K + (BK) channels, which function as a "brake" on the chemosensitive response of LC neurons. Our findings indicate that both Ca 2+ and BK currents develop over the first 2 weeks of postnatal life in rat LC slices and that this brake pathway may cause the developmental decrease in the chemosensitive firing rate response of LC neurons to hypercapnic acidosis. Inhibition of this brake by paxilline (BK channel inhibitor) returns the magnitude of the chemosensitive firing rate response from LC neurons in rats older than P10 to high values similar to those in LC neurons from younger rats. Inhibition of BK channels in LC neurons by bilateral injections of paxilline into the LC results in a significant increase in the hypercapnic ventilatory response of adult rats. Our findings indicate that a BK channel-based braking system helps to determine the chemosensitive respiratory drive of LC neurons and contributes to the hypercapnic ventilatory response. Perhaps, abnormalities of this braking system could result in hypercapnia-induced respiratory disorders and panic responses. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

Left ventricular wall stress and sarcoplasmic reticulum Ca(2+)-ATPase gene expression in renal hypertensive rats: dose-dependent effects of ACE inhibition and AT1-receptor blockade.

Science.gov (United States)

Zierhut, W; Studer, R; Laurent, D; Kästner, S; Allegrini, P; Whitebread, S; Cumin, F; Baum, H P; de Gasparo, M; Drexler, H

1996-05-01

Cardiac hypertrophy is associated with altered Ca2+ handling and may predispose to the development of LV dysfunction and cardiac failure. At the cellular level, the re-expression of ANF represents a well-established marker of myocyte hypertrophy while the decreased expression of the sarcoplasmatic reticulum (SR) Ca(2+)-ATPase is thought o play a crucial role in the alterations of Ca2+ handling and LV function. We assessed the dose-dependent effect of chronic ACE inhibition or AT1 receptor blockade on cardiac function in relation to the cardiac expression of the SR Ca(2+)-ATPase and ANF. Renal hypertensive rats (2K-1C) were treated for 12 weeks with three different doses of the ACE inhibitor benazepril, the AT1-receptor antagonist valsartan (each drug 0.3, 3, and 10 mg/kg per day i.p.) or placebo. LV dimensions, hypertrophy and wall stress were determined in vivo by magnetic resonance imaging and the gene expressions of ANF and SR Ca(2+)-ATPase were quantified by Northern blot. Low doses of both drugs did not affect blood pressure, hypertrophy, systolic wall stress and the ANF and SR Ca(2+)-ATPase gene expression. High doses of each drug reduced systolic blood pressure, wall stress, and LV hypertrophy to a similar extent and to values comparable to normotensive, age-matched rats. In addition, high dose treatment reduced LV end-systolic and end-diastolic volume as compared to untreated 2K-1C animals and normalized the mRNA levels of both ANF and SR Ca(2+)-ATPase (as compared to normotensive animals). We conclude that in this model, high doses of ACE inhibition and AT1-receptor blockade are necessary to normalize systolic blood pressure, LV hypertrophy and systolic LV wall stress which, in turn, is associated with restoration of a normal cardiac phenotype with respect to SR Ca(2+)-ATPase and ANF and normalization of cardiac function.

Rat model of familial combined hyperlipidemia as a result of comparative mapping

Czech Academy of Sciences Publication Activity Database

Ueno, T.; Tremblay, J.; Kuneš, Jaroslav; Zicha, Josef; Dobešová, Zdenka; Pausová, Z.; Deng, A. Y.; Sun, Y.; Jacob, H. J.; Hamet, P.

2004-01-01

Roč. 17, č. 1 (2004), s. 38-47 ISSN 1094-8341 R&D Projects: GA ČR GA305/03/0769; GA AV ČR IAA7011711 Grant - others:CIHR(CA) MOP-11463; CIHR(CA) MT-12574; CIHR(CA) MOP36378; AHA(US) AD-12-FMCQ 0140149N Institutional research plan: CEZ:AV0Z5011922 Keywords : metabolic syndrome * Prague hypertriglyceridemic rat * quantitative trait locus Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.855, year: 2004

Influence of age and magnesium on calcium metabolism in rats

International Nuclear Information System (INIS)

McElroy, S.T.; Link, J.E.; Dowdy, R.P.; Zinn, K.R.; Ellersieck, M.R.

1991-01-01

This study evaluates the effect of dietary magnesium concentration on calcium metabolism in rats of differing ages. Young (3 wk) and old (18 mo) Fischer 344 rats were fed the AIN-76A diet modified to contain either low (218 mg/kg) or adequate (419 mg/kg) Mg for 4 wk. Some rats subsequently underwent a metabolic balance study (12 d duration). Other rats were gavaged with approximately 220 KBq (6 microCi) of 47 Ca; daily fecal and urine collections were made and periodic whole body radioactivity determined. Femurs were removed and analyzed. Calcium retention and balance were not affected by Mg in young rats. In old rats low Mg intake increased apparent Ca balance. Young rats retained about 3.25 times more of the original dose of 47 Ca than did old rats. Young rats retained more 47 Ca in the femur than did old rats; Mg intake had little effect. Aging accelerated Ca turnover rate, and whole body retention data suggest that adequate Mg does not significantly reduce Ca turnover

Modelling Ca2+ bound Troponin in Excitation Contraction Coupling

Directory of Open Access Journals (Sweden)

Henry G. Zot

2016-09-01

Full Text Available To explain disparate decay rates of cytosolic Ca2+ and structural changes in the thin filaments during a twitch, we model the time course of Ca2+ bound troponin (Tn resulting from the free Ca2+ transient of fast skeletal muscle. In fibers stretched beyond overlap, the decay of Ca2+ as measured by a change in fluo 3 fluorescence is significantly slower than the intensity decay of the meridional 1/38.5 nm-1 reflection of Tn; this is not simply explained by considering only the Ca2+ binding properties of Tn alone (Matsuo, T., Iwamoto, H., and Yagi, N. (2010. Biophys. J. 99, 193-200. We apply a comprehensive model that includes the known Ca2+ binding properties of Tn in the context of the thin filament with and without cycling crossbridges. Calculations based on the model predict that the transient of Ca2+ bound Tn correlates with either the fluo 3 time course in muscle with overlapping thin and thick filaments or the intensity of the meridional 1/38.5 nm-1 reflection in overstretched muscle. Hence, cycling crossbridges delay the dissociation of Ca2+ from Tn. Correlation with the fluo 3 fluorescence change is not causal given that the transient of Ca2+ bound Tn depends on sarcomere length, whereas the fluo-3 fluorescence change does not. Transient positions of tropomyosin calculated from the time course of Ca2+ bound Tn are in reasonable agreement with the transient of measured perturbations of the Tn repeat in overlap and non-overlap muscle preparations.

Physiology of spontaneous [Ca2+](i) oscillations in the isolated vasopressin and oxytocin neurones of the rat supraoptic nucleus

Czech Academy of Sciences Publication Activity Database

Kortus, Štěpán; Srinivasan, Ch.; Forostyak, O.; Ueta, Y.; Syková, E.; Chvátal, A.; Zápotocký, Martin; Verkhratsky, A.; Dayanithi, G.

2016-01-01

Roč. 59, č. 6 (2016), s. 280-288 ISSN 0143-4160 R&D Projects: GA ČR(CZ) GBP304/12/G069 Institutional support: RVO:67985823 Keywords : magnocellular neurosecretory cells * supraoptic nucleus * vasopressin * oxytocin * transgenic rats * Ca2+ oscillations Subject RIV: FH - Neurology Impact factor: 3.707, year: 2016

Protective effects of glucose-6-phosphate dehydrogenase on neurotoxicity of aluminium applied into the CA1 sector of rat hippocampus

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Marina D Jovanovic

2014-01-01

Full Text Available Background & objectives: Aluminum (Al toxicity is closely linked to the pathogenesis of Alzheimer′s disease (AD. This experimental study was aimed to investigate the active avoidance behaviour of rats after intrahippocampal injection of Al, and biochemical and immunohistochemical changes in three bilateral brain structures namely, forebrain cortex (FBCx, hippocampus and basal forebrain (BF. Methods: Seven days after intra-hippocampal (CA1 sector injection of AlCl 3 into adult male Wistar rats they were subjected to two-way active avoidance (AA tests over five consecutive days. Control rats were treated with 0.9% w/v saline. The animals were decapitated on the day 12 post-injection. The activities of acetylcholinesterase (AChE and glucose-6-phosphate dehydrogenase (G6PDH were measured in the FBCx, hippocampus and BF. Immunohistochemical staining was performed for transferrin receptors, amyloid β and tau protein. Results: The activities of both AChE and G6PDH were found to be decreased bilaterally in the FBCx, hippocampus and basal forebrain compared to those of control rats. The number of correct AA responses was reduced by AlCl 3 treatment. G6PDH administered prior to AlCl 3 resulted in a reversal of the effects of AlCl 3 on both biochemical and behavioural parameters. Strong immunohistochemical staining of transferrin receptors was found bilaterally in the FBCx and the hippocampus in all three study groups. In addition, very strong amyloid β staining was detected bilaterally in all structures in AlCl 3 -treated rats but was moderate in G6PDH/AlCl 3 -treated rats. Strong tau staining was noted bilaterally in AlCl 3 -treated rats. In contrast, tau staining was only moderate in G6PDH/AlCl 3 -treated rats. Interpretation & conclusions: Our findings indicated that the G6PDH alleviated the signs of behavioural and biochemical effects of AlCl 3 -treatment suggesting its involvement in the pathogenesis of Al neurotoxicity and its potential

Impaired sarcoplasmic reticulum Ca(2+) release rate after fatiguing stimulation in rat skeletal muscle

DEFF Research Database (Denmark)

Ørtenblad, Niels; Sjøgaard, G; Madsen, Klavs

2000-01-01

during the first 0.5-1 h the metabolic state recovered to resting levels, and a slow phase from 1-3 h characterized by a rather slow recovery of the mechanical properties. The recovery of SR Ca(2+) release rate was closely correlated to +dF/dt during the slow phase of recovery (r(2) = 0.51; P ... to 66% that persisted for 1 h, followed by a gradual recovery to 87% of prefatigue release rate at 3 h recovery. Tetanic force and rate of force development (+dF/dt) and relaxation (-dF/dt) were depressed by approximately 80% after stimulation. Recovery occurred in two phases: an initial phase, in which......The purpose of the study was to characterize the sarcoplasmic reticulum (SR) function and contractile properties before and during recovery from fatigue in the rat extensor digitorum longus muscle. Fatiguing contractions (60 Hz, 150 ms/s for 4 min) induced a reduction of the SR Ca(2+) release rate...

Examining the effect of the CaMKII inhibitor administration in the locus coeruleus on the naloxone-precipitated morphine withdrawal signs in rats.

Science.gov (United States)

Navidhamidi, M; Semnanian, S; Javan, M; Goudarzvand, M; Rohampour, K; Azizi, H

2012-01-15

Drug addiction is an occurrence with physiological, psychological, and social outcomes. Repeated drug exposure causes neuronal adaptations and dependency. It has been shown that CaMKIIα enzyme contributes to morphine dependency. The locus coeruleus nucleus has been implied in the morphine withdrawal syndrome. This research focuses on the behavioral and molecular adaptations that occur in the locus coeruleus neurons in response to the chronic morphine exposure. Adult male Wistar rats were injected by morphine sulfate (10 mg/kg/s.c.) at an interval of 12 h for a period of nine subsequent days. On the tenth day, naloxone (1 mg/kg/i.p.) was injected 2 h after the morphine administration. Somatic withdrawal signs were investigated for 30 min. We concluded that the inhibition of CaMKIIα by administration of KN-93, the specific inhibitor of this enzyme, significantly attenuated some of the withdrawal signs. In molecular method, the expression of CaMKIIα protein has been enhanced in locus coeruleus of the morphine dependent rats. These findings indicate that CaMKIIα may be involved in the modulation of the naloxone-induced withdrawal syndrome, and treatment with KN-93 may have some effects on this system. Copyright © 2011 Elsevier B.V. All rights reserved.

Effect of intrahippocampal CA1 injection of insulin on spatial learning and memory deficits in diabetic rats

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Golbarg Ghiasi

2011-03-01

Full Text Available Background: Diabetes mellitus is one of the most important diseases in all over the world. Insulin and its receptor are found in specific area of CNS with a variety of regions-specific functions different from its role in direct glucose regulation in the periphery. The hippocampus and cerebral cortex distributed insulin and insulin receptor has been shown to be involved in brain cognitive functions. Previous studies about the effect of insulin on memory in diabetes are controversial and further investigation is necessary.Methods: Seventy male NMRI rats (250-300 g were randomly divided into control, diabetic, saline-saline, saline-insulin (12, 18 or 24 mU, diabetic-saline, diabetic-insulin (12, 18 or 24 mU groups. Diabetes was induced by streptozotocin (65 mg/kg, ip. Saline or insulin were injected bilaterally (1 µl/rat into CA1 region of hippocampus during 1 min. Thirty minutes later, water maze training was performed.Results: Insulin had a dose dependent effect. The spatial learning and memory were impaired with diabetes, and improved by insulin. Escape latency and swimming distance in a water maze in insulin treated animals were significantly lower (P<0.05 than control and diabetic groups. Percentage of time spent by animals in a target quarter in probe trial session showed a significant difference among groups. This difference was significant between insulin treated and the other groups (P<0.05.Conclusions: Our findings suggest that injection of insulin into hippocampal CA1 area may have a dose-dependent effect on spatial learning and memory in diabetic rats.

Desipramine inhibits histamine H1 receptor-induced Ca2+ signaling in rat hypothalamic cells.

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Ji-Ah Kang

Full Text Available The hypothalamus in the brain is the main center for appetite control and integrates signals from adipose tissue and the gastrointestinal tract. Antidepressants are known to modulate the activities of hypothalamic neurons and affect food intake, but the cellular and molecular mechanisms by which antidepressants modulate hypothalamic function remain unclear. Here we have investigated how hypothalamic neurons respond to treatment with antidepressants, including desipramine and sibutramine. In primary cultured rat hypothalamic cells, desipramine markedly suppressed the elevation of intracellular Ca(2+ evoked by histamine H1 receptor activation. Desipramine also inhibited the histamine-induced Ca(2+ increase and the expression of corticotrophin-releasing hormone in hypothalamic GT1-1 cells. The effect of desipramine was not affected by pretreatment with prazosin or propranolol, excluding catecholamine reuptake activity of desipramine as an underlying mechanism. Sibutramine which is also an antidepressant but decreases food intake, had little effect on the histamine-induced Ca(2+ increase or AMP-activated protein kinase activity. Our results reveal that desipramine and sibutramine have different effects on histamine H1 receptor signaling in hypothalamic cells and suggest that distinct regulation of hypothalamic histamine signaling might underlie the differential regulation of food intake between antidepressants.

Mechanism of the negative force-frequency relationship in physiologically intact rat ventricular myocardium. Studies by intracellular Ca2+ monitor with iodo-1 and by 31P-nuclear magnetic resonance spectroscopy

International Nuclear Information System (INIS)

Morii, Isao; Kihara, Yasuki; Sasayama, Shigetake; Konishi, Takashi; Inubushi, Toshiro.

1996-01-01

We studied the subcellular mechanisms of the negative force-frequency relationship in rat myocardium by measuring intracellular Ca 2+ transients by indo-1 fluorometry and intracellular pH (pH i ) and phosphate compounds with 31 P-nuclear magnetic resonance (NMR). The data were compared with those from guinea pig hearts, which show a positive force-frequency relationship. By increasing the pacing rate from 3 Hz to 5 Hz, the peak positive first derivative of left ventricular pressure (LVdP/dt) in rat heart decreased by 10±1% (n=6). In contrast to this negative inotropic response, simultaneously measured peak Ca 2+ transients increased by 6±1%. Guinea pig heart (n=6) showed an increase in peak positive LVdP/dt (33±1%) which was associated with an increase in peak Ca 2+ transients (8±1%). Under equivalent experimental conditions in an NMR spectrometer, this increase in the pacing rate did not affect intracellular levels of phosphate compounds in either rat (n=6) or guinea pig heart (n=6). In contrast, pH i showed a decrease of 0.031±0.006 pH units in rat heart, while no changes were observed in guinea pig heart. These results suggest that in physiological rat myocardium, pH i is susceptible to changes in the stimulus frequency and may affect the Ca 2+ -responsiveness of contractile proteins, which results in the negative force-frequency relationship. (author)

[Effects of Total Alkaloids of Harmaline on Learning and Memory in Vascular Dementia Rats].

Science.gov (United States)

Zhang, Xiao-shuang; Sun, Jian-ning; Yu, Hui-ling

2015-11-01

To investigate the effects of total alkaloids of harmaline on learning and memory in vascular dementia rats, and its mechanism. The model rats of vascular dementia were established with bilateral carotid artery ligation. After 30 days, the model rats were randomly divided into six groups: sham group, model group, nicergoline tablets 7 mg/kg group, and 25, 12.5 and 6.25 mg/kg dose groups of total alkaloids of harmaline, the rats were given medicine for 30 days. Learning and memory abilities were tested by Morris water maze, histomorphology in hippocampal CA1 area were observed by HE staining, BAX and BCL-2 protein expression in hippocampal CA1 area were detected by immunohistochemistry. Compared with model group, 25 mg/kg group of total alkaloids of harmaline shortened the incubation period in the third and fourth day significantly, 12.5 mg/kg group of total alkaloids of harmaline shortened the incubation period in the fourth day. 25 and 12.5 mg/kg groups of total alkaloids of harmaline significantly increased the times crossing the target. Total alkaloids of harmaline improved the neurons pathological changes of rat in the hippocampus CA1 area, 25 and 12.5 mg/kg of total alkaloids of harmaline downregulated the expression of apoptosis proteins BAX, upregulated the protein expression of BCL-2. Total alkaloids of harmaline can improve the learning and memory abilities in vascular dementia rats, which probably is related to inhibiting apoptosis of hippocampus cell.

Hierarchic stochastic modelling applied to intracellular Ca(2+ signals.

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Gregor Moenke

Full Text Available Important biological processes like cell signalling and gene expression have noisy components and are very complex at the same time. Mathematical analysis of such systems has often been limited to the study of isolated subsystems, or approximations are used that are difficult to justify. Here we extend a recently published method (Thurley and Falcke, PNAS 2011 which is formulated in observable system configurations instead of molecular transitions. This reduces the number of system states by several orders of magnitude and avoids fitting of kinetic parameters. The method is applied to Ca(2+ signalling. Ca(2+ is a ubiquitous second messenger transmitting information by stochastic sequences of concentration spikes, which arise by coupling of subcellular Ca(2+ release events (puffs. We derive analytical expressions for a mechanistic Ca(2+ model, based on recent data from live cell imaging, and calculate Ca(2+ spike statistics in dependence on cellular parameters like stimulus strength or number of Ca(2+ channels. The new approach substantiates a generic Ca(2+ model, which is a very convenient way to simulate Ca(2+ spike sequences with correct spiking statistics.

The effect of gallic acid on cytotoxicity, Ca(2+) homeostasis and ROS production in DBTRG-05MG human glioblastoma cells and CTX TNA2 rat astrocytes.

Science.gov (United States)

Hsu, Shu-Shong; Chou, Chiang-Ting; Liao, Wei-Chuan; Shieh, Pochuen; Kuo, Daih-Huang; Kuo, Chun-Chi; Jan, Chung-Ren; Liang, Wei-Zhe

2016-05-25

Gallic acid, a polyhydroxylphenolic compound, is widely distributed in various plants, fruits and foods. It has been shown that gallic acid passes into blood brain barrier and reaches the brain tissue of middle cerebral artery occlusion rats. However, the effect of gallic acid on Ca(2+) signaling in glia cells is unknown. This study explored whether gallic acid affected Ca(2+) homeostasis and induced Ca(2+)-associated cytotoxicity in DBTRG-05MG human glioblastoma cells and CTX TNA2 rat astrocytes. Gallic acid (20-40 μM) concentration-dependently induced cytotoxicity and intracellular Ca(2+) level ([Ca(2+)]i) increases in DBTRG-05MG cells but not in CTX TNA2 cells. In DBTRG-05MG cells, the Ca(2+) response was decreased by half by removal of extracellular Ca(2+). In Ca(2+)-containing medium, gallic acid-induced Ca(2+) entry was inhibited by store-operated Ca(2+) channel inhibitors (2-APB, econazole and SKF96365). In Ca(2+)-free medium, pretreatment with the endoplasmic reticulum Ca(2+) pump inhibitor thapsigargin abolished gallic acid-induced [Ca(2+)]i increases. Conversely, incubation with gallic acid also abolished thapsigargin-induced [Ca(2+)]i increases. Inhibition of phospholipase C with U73122 abolished gallic acid-induced [Ca(2+)]i increases. Gallic acid significantly caused cytotoxicity in DBTRG-05MG cells, which was partially prevented by prechelating cytosolic Ca(2+) with BAPTA-AM. Moreover, gallic acid activated mitochondrial apoptotic pathways that involved ROS production. Together, in DBTRG-05MG cells but not in CTX TNA2 cells, gallic acid induced [Ca(2+)]i increases by causing Ca(2+) entry via 2-APB, econazole and SKF96365-sensitive store-operated Ca(2+) entry, and phospholipase C-dependent release from the endoplasmic reticulum. This Ca(2+) signal subsequently evoked mitochondrial pathways of apoptosis that involved ROS production. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Intestinal absorption of calcium and magnesium in rats

International Nuclear Information System (INIS)

Erhart, J.

1981-01-01

Absorption of Ca and Mg was studied in isolated and perfused jejunum segments of rats using radioactive 45 Ca and 28 Mg. At ion concentrations of 1.5 and 10 mmol in the bath solution, the influence of uraemia, 1,25-(OH) 2 D 3 and the complementary ion was investigated. Absorption of Ca ++ was found to be slightly reduced by uraemia and renormalized by 1,25-(OH) 2 D 3 substitution. Transport of Ca ++ was significantly increased in the presence of Mg ++ , both in healthy rats and in animals with chronic uraemia. Mg ++ absorption, in contrast, was significantly reduced in rats with uraemia, and 1,25-(OH) 2 D 3 substitution was found to reduce it even further. In the presence of Ca ++ , transport of Mg ++ was lowered both in healthy rats and in rats with chronic uraemia. (MG) [de

A dynamic model of interactions of Ca2+, calmodulin, and catalytic subunits of Ca2+/calmodulin-dependent protein kinase II.

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Shirley Pepke

2010-02-01

Full Text Available During the acquisition of memories, influx of Ca2+ into the postsynaptic spine through the pores of activated N-methyl-D-aspartate-type glutamate receptors triggers processes that change the strength of excitatory synapses. The pattern of Ca2+influx during the first few seconds of activity is interpreted within the Ca2+-dependent signaling network such that synaptic strength is eventually either potentiated or depressed. Many of the critical signaling enzymes that control synaptic plasticity,including Ca2+/calmodulin-dependent protein kinase II (CaMKII, are regulated by calmodulin, a small protein that can bindup to 4 Ca2+ ions. As a first step toward clarifying how the Ca2+-signaling network decides between potentiation or depression, we have created a kinetic model of the interactions of Ca2+, calmodulin, and CaMKII that represents our best understanding of the dynamics of these interactions under conditions that resemble those in a postsynaptic spine. We constrained parameters of the model from data in the literature, or from our own measurements, and then predicted time courses of activation and autophosphorylation of CaMKII under a variety of conditions. Simulations showed that species of calmodulin with fewer than four bound Ca2+ play a significant role in activation of CaMKII in the physiological regime,supporting the notion that processing of Ca2+ signals in a spine involves competition among target enzymes for binding to unsaturated species of CaM in an environment in which the concentration of Ca2+ is fluctuating rapidly. Indeed, we showed that dependence of activation on the frequency of Ca2+ transients arises from the kinetics of interaction of fluctuating Ca2+with calmodulin/CaMKII complexes. We used parameter sensitivity analysis to identify which parameters will be most beneficial to measure more carefully to improve the accuracy of predictions. This model provides a quantitative base from which to build more complex dynamic

The effects of CCK-8S on spatial memory and long-term potentiation at CA1 during induction of stress in rats

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Malihe Sadeghi

2017-12-01

Full Text Available Objective(s: Cholecystokinin (CCK has been proposed as a mediator in stress. However, it is still not fully documented what are its effects. We aimed to evaluate the effects of systemic administration of CCK exactly before induction of stress on spatial memory and synaptic plasticity at CA1 in rats. Materials and Methods: Male Wistar rats were divided into 4 groups: the control, the control-CCK, the stress and the stress-CCK. Restraint stress was induced 6 hr per day, for 24 days. Cholecystokinin sulfated octapeptide (CCK-8S was injected (1.6 µg/kg, IP before each session of stress induction. Spatial memory was evaluated by Morris water maze test. Long term potentiation (LTP in Schaffer collateral-CA1 synapses was assessed (by 100 Hz tetanization in order to investigate synaptic plasticity. Results: Stress impaired spatial memory significantly (P

[Establishment of rat model of psychical erectile dysfunction].

Science.gov (United States)

Wang, Qiu-lin; Wang, Shu-ren; Duan, Jin

2006-01-01

To set up a method of establishing the animal model of psychical erectile dysfunction with emotional stress. All thirty-six male rats with normal sexual function were divided into three groups, i. e. normal group, model group and demasculinized group randomly according to their weights. The rats in the model group were suspended upside down in midair over the water and irritated repeatedly. Two weeks later, the sexual abilities of all rats, i. e. the times of mounting and intromitting the estrus female rats, the latent period of mounting, intromission and ejaculation, were recorded, and the number of rats that had sexual activities was also counted. And the hemorheology indices of the rats were measured. Compared with the normal rats, the latency of mounting [(152.5 +/- 24.6) s vs (42.4 +/- 9.6) s] and intromission [(437.0 +/- 67.7) s vs (130.8 +/- 39.1) s] of the model rats were longer (P 0.05). The hemorheology indices, e. g. blood viscosity, hematocrit (Hct) and red cell aggregation (RCA), of the model rats was significant higher than that of the normal and demasculinized rats (P erectile dysfunction can be made ideally with psychical stress.

Comparison of the effects of caffeine and other methylxanthines on [Ca2+]i in rat ventricular myocytes.

Science.gov (United States)

Donoso, P.; O'Neill, S. C.; Dilly, K. W.; Negretti, N.; Eisner, D. A.

1994-01-01

1. The effects of caffeine and other methylxanthines were investigated on intracellular calcium concentration ([Ca2+]i) and contraction in rat isolated ventricular myocytes. The use of the fluorescent indicator, Indo-1, allowed simultaneous measurement of [Ca2+]i and the intracellular concentration of the methylxanthines. 2. Rapid application of caffeine (10 mM) produced a transient rise of [Ca2+]i which decayed to resting levels. This was accompanied by a transient contraction which decayed to a level above baseline. The addition of theophylline also produced a transient increase of [Ca2+]i. However, following the initial transient, contraction decayed before redeveloping to a maintained level. 3. Direct measurements showed that [caffeine]i rose more quickly than did [theophylline]i. The slower rise of [theophylline]i was associated with a delay in the increase of [Ca2+]i. At lower concentrations of the methylxanthines, theophylline was less effective than caffeine at initiating Ca release. The rate of entry of theobromine was similar to that of theophylline. 4. Isocaffeine did not produce a rise of [Ca2+]i. The rate of rise of [isocaffeine]i was much slower than that of either caffeine or theophylline. 5. Measurements of the oil:water partition coefficient showed that the order of relative partitioning into oil was: caffeine > theophylline > theobromine > isocaffeine. This is similar to the order of rate of entry into the cell. 6. We conclude that many of the differences in the effects of these methylxanthines can be attributed to differences in membrane permeability due to differences in oil:water partition. PMID:8004389

Rapid effects of 17beta-estradiol on TRPV5 epithelial Ca2+ channels in rat renal cells.

LENUS (Irish Health Repository)

Irnaten, Mustapha

2009-08-01

The renal distal tubules and collecting ducts play a key role in the control of electrolyte and fluid homeostasis. The discovery of highly calcium selective channels, Transient Receptor Potential Vanilloid 5 (TRPV5) of the TRP superfamily, has clarified the nature of the calcium entry channels. It has been proposed that this channel mediates the critical Ca(2+) entry step in transcellular Ca(2+) re-absorption in the kidney. The regulation of transmembrane Ca(2+) flux through TRPV5 is of particular importance for whole body calcium homeostasis.In this study, we provide evidence that the TRPV5 channel is present in rat cortical collecting duct (RCCD(2)) cells at mRNA and protein levels. We demonstrate that 17beta-estradiol (E(2)) is involved in the regulation of Ca(2+) influx in these cells via the epithelial Ca(2+) channels TRPV5. By combining whole-cell patch-clamp and Ca(2+)-imaging techniques, we have characterized the electrophysiological properties of the TRPV5 channel and showed that treatment with 20-50nM E(2) rapidly (<5min) induced a transient increase in inward whole-cell currents and intracellular Ca(2+) via TRPV5 channels. This rise was significantly prevented when cells were pre-treated with ruthenium red and completely abolished in cells treated with siRNA specifically targeting TRPV5.These data demonstrate for the first time, a novel rapid modulation of endogenously expressed TRPV5 channels by E(2) in kidney cells. Furthermore, the results suggest calcitropic effects of E(2). The results are discussed in relation to present concepts of non-genomic actions of E(2) in Ca(2+) homeostasis.

The Effect of N-acetyl-cysteine on Memory Retrieval and the Number of Intact Neurons of Hippocampal CA1 Area in Streptozotocin-induced Alzheimeric Male Rats

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Niloufar Darbandi

2018-01-01

Full Text Available Abstract Background: Alzheimer is a neurodegenerative disease wich caused memory impairment, reduced cognitive functions, intellectual ability and behavior changes. In this study, the effect of N-acetyl-cysteine (NAC as a strong antioxidant on memory deficiency and number of CA1 pyramidal neurons in Streptozotocine (STZ - induced Alzheimeric rats were studied. Materials and Methods: 32 Male Wistar rats were divided into four groups: sham group, streptozotocin group, treated group with streptozotocin plus N-acetyl-cysteine, and treated group with N-acetyl-cysteine alone. Intracerebroventricular (ICV administration of STZ was done in the first and the third day of surgery and i.p injection of N-acetyl-cysteine was done in the fourth of surgery. After the memory test, the animals were killed and their brains were fixed and density of intact neurons in the CA1 area of the hippocampus was investigated. Statistical analysis was performed with software SPSS, ANOVA and Prisme software. The level of statistical significance was set at p 0.05. Conclusion: N-acetyl-cysteine improved memory retrieval and hippocampal CA1 area intact neurons in streptozotocin-induced Alzheimeric male rats.

Purinergic receptors stimulate Na+/Ca2+ exchange in pancreatic duct cells: possible role of proteins handling and transporting Ca2+

DEFF Research Database (Denmark)

Hansen, Mette R; Krabbe, Simon; Ankorina-Stark, Ieva

2009-01-01

). Since NCX can also be connected with epithelial Ca(2+) transport, we also investigated expression of some Ca(2+)-handling/transporting proteins. Expression analysis revealed that pancreatic ducts of rat and human duct cell line CFPAC-1 (also PANC-1 and Capan-1) express the Na(+)/Ca(2+) exchanger (splice...

Enhanced neuroprotective efficacy of bone marrow mesenchymal stem cells co-overexpressing BDNF and VEGF in a rat model of cardiac arrest-induced global cerebral ischemia

Science.gov (United States)

Zhou, Lili; Lin, Qingming; Wang, Peng; Yao, Lan; Leong, Kahong; Tan, Zhiqun; Huang, Zitong

2017-01-01

Cardiac arrest-induced global cerebral ischemia injury (CA-GCII) usually leads to a poor neurological outcome without an effective treatment. Bone marrow-derived mesenchymal stem cells (BMMSCs) may provide a potential cell-based therapy against neurologic disorders through induction of brain-derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF). To optimize the neuroprotective efficacy of BMMSCs further, in this study we have derived BMMSCs, which co-overexpress both BDNF and VEGF, and tested them for the treatment of CA-GCII in a rat model. Lentiviruses that express rat BDNF exon IV or VEGF-A were created using the bicistronic shuttle vectors of pLVX-IRES-ZsGreen1 and pLVX-IRES-tdTomato, respectively. BMMSCs that were co-transduced with the engineered lentiviruses with co-overexpression of both BDNF and VEGF along with corresponding fluorescent protein reporters were injected via jugular vein of rats that just recovered from a cardiac arrest. Animals were then scored for neurofunctional deficits and examined for brain pathology and gene expression relevant to the engraftment seven days after the treatments. We demonstrate that anchorage of lentiviral vector-transduced BMMSCs, which co-overexpressed both BDNF and VEGF in the hippocampus and temporal cortex along with significantly ameliorated brain pathology and improved neurofunctional performance in CA-GCII rats after transplantation. These findings provide a proof of concept for the further validation of engineered BMMSCs for the treatment of CA-GCII patients in clinical practice in the future. PMID:28492549

A model of cardiac ryanodine receptor gating predicts experimental Ca2+-dynamics and Ca2+-triggered arrhythmia in the long QT syndrome

Science.gov (United States)

Wilson, Dan; Ermentrout, Bard; Němec, Jan; Salama, Guy

2017-09-01

Abnormal Ca2+ handling is well-established as the trigger of cardiac arrhythmia in catecholaminergic polymorphic ventricular tachycardia and digoxin toxicity, but its role remains controversial in Torsade de Pointes (TdP), the arrhythmia associated with the long QT syndrome (LQTS). Recent experimental results show that early afterdepolarizations (EADs) that initiate TdP are caused by spontaneous (non-voltage-triggered) Ca2+ release from Ca2+-overloaded sarcoplasmic reticulum (SR) rather than the activation of the L-type Ca2+-channel window current. In bradycardia and long QT type 2 (LQT2), a second, non-voltage triggered cytosolic Ca2+ elevation increases gradually in amplitude, occurs before overt voltage instability, and then precedes the rise of EADs. Here, we used a modified Shannon-Puglisi-Bers model of rabbit ventricular myocytes to reproduce experimental Ca2+ dynamics in bradycardia and LQT2. Abnormal systolic Ca2+-oscillations and EADs caused by SR Ca2+-release are reproduced in a modified 0-dimensional model, where 3 gates in series control the ryanodine receptor (RyR2) conductance. Two gates control RyR2 activation and inactivation and sense cytosolic Ca2+ while a third gate senses luminal junctional SR Ca2+. The model predicts EADs in bradycardia and low extracellular [K+] and cessation of SR Ca2+-release terminate salvos of EADs. Ca2+-waves, systolic cell-synchronous Ca2+-release, and multifocal diastolic Ca2+ release seen in subcellular Ca2+-mapping experiments are observed in the 2-dimensional version of the model. These results support the role of SR Ca2+-overload, abnormal SR Ca2+-release, and the subsequent activation of the electrogenic Na+/Ca2+-exchanger as the mechanism of TdP. The model offers new insights into the genesis of cardiac arrhythmia and new therapeutic strategies.

Vorinostat ameliorates impaired fear extinction possibly via the hippocampal NMDA-CaMKII pathway in an animal model of posttraumatic stress disorder.

Science.gov (United States)

Matsumoto, Yasutaka; Morinobu, Shigeru; Yamamoto, Shigeto; Matsumoto, Tomoya; Takei, Shiro; Fujita, Yosuke; Yamawaki, Shigeto

2013-09-01

Given that impairment of fear extinction plays a pivotal role in the pathophysiology of posttraumatic stress disorder (PTSD), drugs that facilitate fear extinction may be useful as novel treatments for PTSD. Histone deacetylase (HDAC) inhibitors have recently been shown to enhance fear extinction in animal studies. Using a single prolonged stress (SPS) paradigm, an animal model of PTSD, we examined whether the HDAC inhibitor vorinostat can facilitate fear extinction in rats, and elucidated the mechanism by which vorinostat enhanced fear extinction, focusing on the N-methyl-D-aspartate (NMDA) receptor signals in the hippocampus. Seven days after SPS, rats received contextual fear conditioning, followed by 2-day extinction training. Vorinostat was intraperitoneally injected immediately after second extinction training session. Contextual fear response was assessed 24 h after vorinostat injection. Hippocampal tissues were dissected 2 h after vorinostat injection. The levels of mRNA and protein tested were measured by RT-PCR or western blotting, respectively. Systemic administration of vorinostat with extinction training significantly enhanced fear extinction in SPS rats as compared with the controls. Furthermore, vorinostat enhanced the hippocampal levels of NR2B and calcium/calmodulin kinase II (CaMKII) α and β proteins, accompanied by increases in the levels of acetylated histone H3 and H4. These findings suggest that vorinostat ameliorated the impaired fear extinction in SPS rats, and this effect was associated with an increase in histone acetylation and thereby enhancement of NR2B and CaMKII in the hippocampus. Our results may provide new insight into the molecular and therapeutic mechanisms of PTSD.

Ebselen increases cytosolic free Ca2+ concentration, stimulates glutamate release and increases GFAP content in rat hippocampal astrocytes

International Nuclear Information System (INIS)

Salazar, Miguel; Pariente, Jose Antonio; Salido, Gines Maria; Gonzalez, Antonio

2008-01-01

We have investigated the effect of the seleno-organic compound and radical scavenger ebselen on rat hippocampal astrocytes in culture. Throughout our study we carried out determinations of [Ca 2+ ] c in fura-2-loaded cells by single cell imaging, glutamate secretion employing an enzymatic-based assay and GFAP expression, which was monitorized by immunocytochemistry and confocal microscopy. Our results show that ebselen (1-20 μM) dose dependently increases [Ca 2+ ] c , stimulates glutamate release and increases GFAP content, a hallmark of astrocyte reactivity. Ebselen did not alter significantly cell viability as assayed by determination of LDH release into the extracellular medium. Ebselen-evoked glutamate release and increase in GFAP content were Ca 2+ -dependent, because incubation of astrocytes in the absence of extracellular Ca 2+ (medium containing 0.5 mM EGTA) and in the presence of the intracellular Ca 2+ chelator BAPTA (10 μM) significantly reduced ebselen-evoked changes in these parameters. The effects of ebselen we have observed may underline various signalling pathways which are important for cell proliferation, differentiation and function. However, aberrations in astroglial physiology could significantly compromise brain function, due to their role as modulators of neuron activity. Therefore, we consider that careful attention should be paid when employing ebselen as a prophylactic agent against brain damage

Development and comparison of a minimally-invasive model of autologous clot pulmonary embolism in Sprague-Dawley and Copenhagen rats

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Sanapareddy Nina

2010-02-01

Full Text Available Abstract Background Experimental models of pulmonary embolism (PE that produce pulmonary hypertension (PH employ many different methods of inducing acute pulmonary occlusion. Many of these models induce PE with intravenous injection of exogenous impervious objects that may not completely reproduce the physiological properties of autologous thromboembolism. Current literature lacks a simple, well-described rat model of autlogous PE. Objective: Test if moderate-severity autologous PE in Sprague-Dawley (SD and Copenhagen (Cop rats can produce persistent PH. Methods blood was withdrawn from the jugular vein, treated with thrombin-Ca++ and re-injected following pretreatment with tranexamic acid. Hemodynamic values, clot weights and biochemical measurements were performed at 1 and 5 days. Results Infusion of clot significantly increased the right ventricular peak systolic pressure to 45-55 mm Hg, followed by normalization within 24 hours in SD rats, and within 5 days in COP rats. Clot lysis was 95% (24 hours and 97% (5 days in SD rats and was significantly lower in COP rats (70%, 24 hours; 87% 5 days. Plasma D-dimer was elevated in surgical sham animals and was further increased 8 hours after pulmonary embolism. Neither strain showed a significant increase in bronchoalveolar chemotactic activity, myeloperoxidase activity, leukocyte infiltration, or chemokine accumulation, indicating that there was no significant pulmonary inflammation. Conclusions Both SD and COP rats exhibited near complete fibrinolysis of autologous clot PE within 5 days. Neither strain developed persistent PH. Experimental models of PE designed to induce sustained PH and a robust inflammatory response appear to require significant, persistent pulmonary vascular occlusion.

Ghrelin increases intracellular Ca²⁺ concentration in the various hormone-producing cell types of the rat pituitary gland.

Science.gov (United States)

Yamazaki, Mami; Aizawa, Sayaka; Tanaka, Toru; Sakai, Takafumi; Sakata, Ichiro

2012-09-20

Ghrelin, isolated from the stomach as an endogenous ligand for the growth hormone secretagogue receptor (GHS-R), has potent growth hormone release ability in vivo and in vitro. Although GHS-R is abundantly expressed in the pituitary gland, there is no direct evidence of a relationship between hormone-producing cells and functional GHS-R in the pituitary gland. The aim of this study was to determine which anterior pituitary cells respond to ghrelin stimulation in male rats. We performed Fura-2 Ca(2+) imaging analysis using isolated pituitary cells, and performed immunocytochemistry to identify the type of pituitary hormone-producing cells. In Fura-2 Ca(2+) imaging analysis, ghrelin administration increased the intracellular Ca(2+) concentration in approximately 50% of total isolated anterior pituitary cells, and 20% of these cells strongly responded to ghrelin. Immunocytochemical analysis revealed that 82.9 ± 1.3% of cells that responded to ghrelin stimulation were GH-immunopositive. On the other hand, PRL-, LH-, and ACTH-immunopositive cells constituted 2.0 ± 0.3%, 12.6 ± 0.3%, and 2.5 ± 0.8% of ghrelin-responding pituitary cells, respectively. TSH-immunopositive cells did not respond to ghrelin treatment. These results suggest that ghrelin directly acts not only on somatotrophs, but also on mammotrophs, gonadotrophs, and corticotrophs in the rat pituitary gland. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Effects of FK506 on Hippocampal CA1 Cells Following Transient Global Ischemia/Reperfusion in Wistar Rat

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Zahra-Nadia Sharifi

2012-01-01

Full Text Available Transient global cerebral ischemia causes loss of pyramidal cells in CA1 region of hippocampus. In this study, we investigated the neurotrophic effect of the immunosuppressant agent FK506 in rat after global cerebral ischemia. Both common carotid arteries were occluded for 20 minutes followed by reperfusion. In experimental group 1, FK506 (6 mg/kg was given as a single dose exactly at the time of reperfusion. In the second group, FK506 was administered at the beginning of reperfusion, followed by its administration intraperitoneally (IP 6, 24, 48, and 72 hours after reperfusion. FK506 failed to show neurotrophic effects on CA1 region when applied as a single dose of 6 mg/kg. The cell number and size of the CA1 pyramidal cells were increased, also the number of cell death decreased in this region when FK506 was administrated 48 h after reperfusion. This work supports the possible use of FK506 in treatment of ischemic brain damage.

A comparative study on the effect of high cholesterol diet on the hippocampal CA1 area of adult and aged rats.

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Abo El-Khair, Doaa M; El-Safti, Fatma El-Nabawia A; Nooh, Hanaa Z; El-Mehi, Abeer E

2014-06-01

Dementia is one of the most important problems nowadays. Aging is associated with learning and memory impairments. Diet rich in cholesterol has been shown to be detrimental to cognitive performance. This work was carried out to compare the effect of high cholesterol diet on the hippocampus of adult and aged male albino rats. Twenty adult and twenty aged male rats were used in this study. According to age, the rats were randomly subdivided into balanced and high cholesterol diet fed groups. The diet was 15 g/rat/day for adult rats and 20 g/rat/day for aged rats for eight weeks. Serial coronal sections of hippocampus and blood samples were taken from each rat. For diet effect evaluation, Clinical, biochemical, histological, immunohistochemical, and morphometric assessments were done. In compare to a balanced diet fed rat, examination of Cornu Ammonis 1 (CA 1) area in the hippocampus of the high cholesterol diet adult rats showed degeneration, a significant decrease of the pyramidal cells, attenuation and/or thickening of small blood vessels, apparent increase of astrocytes and apparent decrease of Nissl's granules content. Moreover, the high cholesterol diet aged rats showed aggravation of senility changes of the hippocampus together with Alzheimer like pathological changes. In conclusion, the high cholesterol diet has a significant detrimental effect on the hippocampus and aging might pronounce this effect. So, we should direct our attention to limit cholesterol intake in our food to maintain a healthy life style for a successful aging.

Expression of Toll-like receptor 4 in hippocampus of rat model with temporal lobe epilepsy

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PAN Li-ping

2013-12-01

Full Text Available Objective To investigate the expression of Toll-like receptor 4 (TLR4 protein in hippocampus of rat model with temporal lobe epilepsy after status epilepticus (SE and explore its function in the pathogenesis of temporal lobe epilepsy. Methods Rat model with temporal lobe epilepsy was induced by lithium chloride (LiCl-pilocarpine. Total protein was extracted from hippocampus and rat brain slices were obtained at different time points (0, 1, 6, 12, 24, 48 h and 7, 10, 30, 50 d after SE. Western blotting and immunohistochemical staining were used for detection of the expression of TLR4 in the hippocampus. Results The results of Western blotting showed the TLR4 protein expression at 0, 1, 6, 12, 24, 48 h and 7, 10, 30 d after SE was higher than that in the control group (P 0.05. Conclusion TLR4 protein was mainly expressed in cytoplasm of pyramidal cells in CA3 area of hippocampus. TLR4 protein expression in the hippocampus was increased in varying degrees at different observation time points after SE, indicating that TLR4 may play an important role in the development of epilepsy.

Ca2+ influx and efflux in animal cells in the presence of panax notoginseng extracts: investigated by using 45Ca as a radioactive tracer

International Nuclear Information System (INIS)

Yang Yuanyou; Liu Ning; Mo Shangwu; Liao Jiali; Xu Falun

2010-01-01

In this paper, the influence of extracts of Panax notoginseng on Ca 2+ influx and efflux in isolated rat visceral organs was investigated by using 45 Ca as a radioactive tracer. The results indicated that both extracts, the total flavonoids and total saponins of Panax notoginseng had significant influence on Ca 2+ influx and efflux in the isolated rat aorta, heart, and kidney, in those organs it could markedly block 45 Ca entering into cell and could facilitate efflux of intracellular Ca 2+ . Compared with the total flavonoids, total saponins had stronger role in the regulation of Ca 2+ influx and efflux. Also, regulation effects of Ca 2+ influx and efflux of the total saponins were compared with positive drug Verapamil, or even better. This implies that the total flavonoids and total saponins of Panax notoginseng have calcium antagonistic effect, and both may be the active ingredients in Panax notoginseng for coronary heart disease treatment. (authors)

Role of suppressed hepatocellular regeneration and Ca2+ in chlordecone-potentiated CCl4 hepatotoxicity

International Nuclear Information System (INIS)

Bell, A.N.

1987-01-01

The mechanism by which the chlorinated pesticide chlordecone (CD; Kepone) potentiates CCl 4 -induced hepatotoxicity and lethality was investigated. It was hypothesized that perturbations in Ca 2+ homeostasis, greater than those observed with a low dose of CCl 4 alone, in concert with a suppression of hepatocellular regeneration induced by CD alone or by CD + CCl 4 are responsible, at least in part, for CD-potentiated CCl 4 hepatotoxicity. Ca 2+ homeostasis was evaluated by measuring total cell Ca 2+ and 45 Ca 2+ uptake in viable isolated hepatocyte suspension obtained from normal and CD-pretreated rats receiving CCl 4 in vivo. In the normal rats in vivo CCL challenge did not affect 45 Ca 2+ uptake by viable isolated hepatocytes. In contrast, 45 Ca 2+ uptake was inhibited in viable isolated hepatocytes obtained from rats exposed to CD + CCl 4

Dopamine D1-like receptor in lateral habenula nucleus affects contextual fear memory and long-term potentiation in hippocampal CA1 in rats.

Science.gov (United States)

Chan, Jiangping; Guan, Xin; Ni, Yiling; Luo, Lilu; Yang, Liqiang; Zhang, Pengyue; Zhang, Jichuan; Chen, Yanmei

2017-03-15

The Lateral Habenula (LHb) plays an important role in emotion and cognition. Recent experiments suggest that LHb has functional interaction with the hippocampus and plays an important role in spatial learning. LHb is reciprocally connected with midbrain monoaminergic brain areas such as the ventral tegmental area (VTA). However, the role of dopamine type 1 receptor (D1R) in LHb in learning and memory is not clear yet. In the present study, D1R agonist or antagonist were administered bilaterally into the LHb in rats. We found that both D1R agonist and antagonist impaired the acquisition of contextual fear memory in rats. D1R agonist or antagonist also impaired long term potentiation (LTP) in hippocampal CA3-CA1 synapses in freely moving rats and attenuated learning induced phosphorylation of α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor (AMPAR) subunit 1 (GluA1) at Ser831 and Ser845 in hippocampus. Taken together, our results suggested that dysfunction of D1R in LHb affected the function of hippocampus. Copyright © 2016 Elsevier B.V. All rights reserved.

Epigenetic modification of hippocampal Bdnf DNA in adult rats in an animal model of post-traumatic stress disorder.

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Roth, Tania L; Zoladz, Phillip R; Sweatt, J David; Diamond, David M

2011-07-01

Epigenetic alterations of the brain-derived neurotrophic factor (Bdnf) gene have been linked with memory, stress, and neuropsychiatric disorders. Here we examined whether there was a link between an established rat model of post-traumatic stress disorder (PTSD) and Bdnf DNA methylation. Adult male Sprague-Dawley rats were given psychosocial stress composed of two acute cat exposures in conjunction with 31 days of daily social instability. These manipulations have been shown previously to produce physiological and behavioral sequelae in rats that are comparable to symptoms observed in traumatized people with PTSD. We then assessed Bdnf DNA methylation patterns (at exon IV) and gene expression. We have found here that the psychosocial stress regimen significantly increased Bdnf DNA methylation in the dorsal hippocampus, with the most robust hypermethylation detected in the dorsal CA1 subregion. Conversely, the psychosocial stress regimen significantly decreased methylation in the ventral hippocampus (CA3). No changes in Bdnf DNA methylation were detected in the medial prefrontal cortex or basolateral amygdala. In addition, there were decreased levels of Bdnf mRNA in both the dorsal and ventral CA1. These results provide evidence that traumatic stress occurring in adulthood can induce CNS gene methylation, and specifically, support the hypothesis that epigenetic marking of the Bdnf gene may underlie hippocampal dysfunction in response to traumatic stress. Furthermore, this work provides support for the speculative notion that altered hippocampal Bdnf DNA methylation is a cellular mechanism underlying the persistent cognitive deficits which are prominent features of the pathophysiology of PTSD. Copyright © 2011 Elsevier Ltd. All rights reserved.

Regulated release of Ca2+ from respiring mitochondria by Ca2+/2H+ antiport.

Science.gov (United States)

Fiskum, G; Lehninger, A L

1979-07-25

Simultaneous measurements of oxygen consumption and transmembrane transport of Ca2+, H+, and phosphate show that the efflux of Ca2+ from respiring tightly coupled rat liver mitochondria takes place by an electroneutral Ca2+/2H+ antiport process that is ruthenium red-insensitive and that is regulated by the oxidation-reduction state of the mitochondrial pyridine nucleotides. When mitochondrial pyridine nucleotides are kept in a reduced steady state, the efflux of Ca2+ is inhibited; when they are in an oxidized state, Ca2+ efflux is activated. These processes were demonstrated by allowing phosphate-depleted mitochondria respiring on succinate in the presence of rotenone to take up Ca2+ from the medium. Upon subsequent addition of ruthenium red to block Ca2+ transport via the electrophoretic influx pathway, and acetoacetate, to bring mitochondrial pyridine nucleotides into the oxidized state, Ca2+ efflux and H+ influx ensued. The observed H+ influx/Ca2+ efflux ratio was close to the value 2.0 predicted for the operation of an electrically neutral Ca2+/2H+ antiport process.

The study of the distribution of Ca{sup 45} with time in the newborn rat by the autoradiography method at - 195 deg; Etude de la distribution du {sup 45}Ca en fonction du temps chez le rat nouveau-ne par la methode d'autoradiographie a -195 deg

Energy Technology Data Exchange (ETDEWEB)

Kellershohn, C; Pellerin, P [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1961-07-01

Ca{sup 45} metabolism has been studied as a function of time by autoradiography at -195 deg. C in the new-born rat after sub-epidermal dorsal injected of 20 micro-curies per animal. This study confirms: 1) The existence of a rapidly exchangeable calcium bone fraction; 2) A considerable intestinal excretion of radio-calcium, much greater than the urinary elimination; 3) A gradual transfer of the activity for the long bones of the epiphyseal to the diaphyseal regions during growth, together with secondary modifications during ossification. (author) [French] Le metabolisme du {sup 45}Ca est etudie en fonction du temps par autoradiographie a -195 deg. C, chez le rat nouveau-ne apres injection sous-epidermique dorsale de 20 microcuries par animal. Cette etude confirme: 1) l'existence d'une fraction calcique osseuse rapidement echangeable; 2) une excretion intestinale considerable du radiocalcium, tres superieure a l'elimination urinaire; 3) un transfert progressif de l'activite pour les os longs des regions epiphysaires aux regions diaphysaires au cours de la croissance, ainsi que les remaniements secondaires au cours de l'ossification. (auteur)

Influence of inhaled Ca-DTPA on the long-term effects of inhaled Pu nitrate

International Nuclear Information System (INIS)

Ballou, J.E.; Dagle, G.E.; McDonald, K.E.; Buschbom, R.L.

1975-01-01

Inhaled Ca-DTPA administered to rats in 6 weekly, one-hour treatments of 3 mg/rat did not affect weight gain or life-span compared to Pu burdened animals (78 nCi ILB) or nontreated controls. In addition, the drug did not appear to promote the development of malignant lung tumors and bone tumors in Pu burdened rats although one rat exposed only to Ca-DTPA aerosols did develop a malignant lung tumor. This single lung tumor can not be considered significant although the normal incidence of this lesion is quite low. Inhaled Ca-DTPA therapy administered 20 days after Pu inhalation showed little effect in reducing the lung burden of plutonium. Skeletal deposition was decreased possibly because Ca-DTPA was administered during a time of active translocation of the inhaled Pu when Pu may have been available for chelation in the blood. Inhaled Ca-DTPA therapy did not appear to be beneficial in reducing the number of malignant lung tumors or bone tumors in plutonium burdened rats but on the other hand the chelate did not appear to promote these lesions. (U.S.)

Neuropathological changes in brain cortex and hippocampus in a rat model of Alzheimer's disease.

Science.gov (United States)

Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Rahbar Rooshandel, Nahid; Omidzahir, Shila

2011-01-01

Alzheimer's disease (AD) is a neurodegenerative disorder with progressive loss of cognitive abilities and memory loss. The aim of this study was to compare neuropathological changes in hippocampus and brain cortex in a rat model of AD. Adult male Albino Wistar rats (weighing 250-300 g) were used for behavioral and histopathological studies. The rats were randomly assigned to three groups: control, sham and Beta amyloid (ABeta) injection. For behavioral analysis, Y-maze and shuttle box were used, respectively at 14 and 16 days post-lesion. For histological studies, Nissl, modified Bielschowsky and modified Congo red staining were performed. The lesion was induced by injection of 4 muL of ABeta (1-40) into the hippocampal fissure. In the present study, ABeta (1-40) injection into hippocampus could decrease the behavioral indexes and the number of CA1 neurons in hippocampus. ABeta injection CA1 caused ABeta deposition in the hippocampus and less than in cortex. We observed the loss of neurons in the hippocampus and cerebral cortex and certain subcortical regions. Y-maze test and single-trial passive avoidance test showed reduced memory retention in AD group. We found a significant decreased acquisition of passive avoidance and alternation behavior responses in AD group compared to control and sham group (P<0.0001). Compacted amyloid cores were present in the cerebral cortex, hippocampus and white matter, whereas, scattered amyloid cores were seen in cortex and hippocampus of AD group. Also, reduced neuronal density was indicated in AD group.

Beneficial effects of Acer okamotoanum sap on L-NAME-induced hypertension-like symptoms in a rat model.

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Yang, Hyun; Hwang, Inho; Koo, Tae-Hyoung; Ahn, Hyo-Jin; Kim, Sun; Park, Mi-Jin; Choi, Won-Sil; Kang, Ha-Young; Choi, In-Gyu; Choi, Kyung-Chul; Jeung, Eui-Bae

2012-02-01

The sap of Acer okamotoanum has been termed 'bone-benefit-water' in Korea owing to its mineral and sugar content. In particular, the calcium (Ca) and potassium (K) concentrations of the sap of Acer okamotoanum are 40- and 20-times higher, respectively, than commercial spring water. In the present study, we examined whether Acer okamotoanum sap improves or prevents hypertension-like symptoms in a rat model. Male Sprague-Dawley rats (8-weeks-old) were provided commercial spring water supplemented with 25, 50 or 100% Acer okamotoanum sap, 3% potassium ions (K+) or captopril, and treated daily for 2 weeks with NG-nitro-L-arginine methyl ester (L-NAME; 100 mg/kg/day) by subcutaneous injection, in order to induce hypertensive symptoms. Rats were euthanized 6 h following the final injection. To assess the effect of the sap on hypertension-like symptoms, we examined the mean blood pressure (BP), protein levels and localization of endothelial nitric oxide synthase (eNOS) in the descending aorta of the rats. BP levels were significantly lower in hypertensive rats received 25, 50 and 100% sap compared with rats who were administered only commercial spring water. Protein levels of eNOS were repressed in L-NAME-only-treated rats, but were elevated in the descending aorta of rats administered captopril, K+ water and Acer okamotoanum sap (25, 50 and 100%) up to the level of the sham group provided commercial spring water, and then injected with dimethyl sulfoxide for the same period of time. Localized eNOS protein was abundantly expressed in the perivascular descending aorta adipose tissue of the rats. Taken together, these results demonstrated that the sap of Acer okamotoanum ameliorated high BP induced by L-NAME treatment in a rat model.

Thapsigargin, a tumor promoter, discharges intracellular Ca2+ stores by specific inhibition of the endoplasmic reticulum Ca2(+)-ATPase

DEFF Research Database (Denmark)

Thastrup, Ole; Cullen, P J; Drøbak, B K

1990-01-01

. This hypothesis is strongly supported by the demonstration that thapsigargin causes a rapid inhibition of the Ca2(+)-activated ATPase activity of rat liver microsomes, with an identical dose dependence to that seen in whole cell or isolated microsome Ca2+ discharge. The inhibition of the endoplasmic reticulum...

1,25 (OH)2 vitamin D3-induced 45Ca uptake in vascular myocytes cultured from spontaneously hypertensive and normotensive rats

International Nuclear Information System (INIS)

Xue, Hong; McCarron, D.A.; Bukoski, R.D.

1991-01-01

The effect of 1,25 (OH) 2 vitamin D 3 on basal 45 Ca uptake was examined in vasvular smooth muscle cells cultured from mesenteric arteries of spontaneously hypertensive (SHR) and Wistar Kyoto (WKY) normotensive rats. Basal uptake of 45 Ca was significantly greater in myocytes of WKY than SHR at 5, 10, 30 and 60 min incubation with the isotope. Incubation with 1 ng/ml 1,25 (OH) 2 vitamin D 3 for 48 hr increased basal 45 Ca uptake between 1-10 min in SHR and between 5-10 min in WKY. The dose-response relationship indicated that cells from both strains are equally sensitive to the calciotropic effects of 1,25 (OH) 2 vitamin D 3 with half-maximal stimulation occurring at approximately 0.3-0.4 ng/ml. In cells of both strains maximal stimulation of 45 Ca uptake was achieved only after a 12-24 hr period of incubation with hormone and pretreatment with cycloheximide inhibited 1,24 (OH) 2 vitamin D 3 -enhanced 45 Ca uptake. Although 45 Ca binding by extracellular matrix material was significantly greater in WKY than SHR, 1,25 (OH) 2 vitamin D 3 had no effect on the amount of matrix 45 Ca binding in either strain

Sex differences in pain-related behavior and expression of calcium/calmodulin-dependent protein kinase II in dorsal root ganglia of rats with diabetes type 1 and type 2.

Science.gov (United States)

Ferhatovic, Lejla; Banozic, Adriana; Kostic, Sandra; Sapunar, Damir; Puljak, Livia

2013-06-01

Sex differences in pain-related behavior and expression of calcium/calmodulin dependent protein kinase II (CaMKII) in dorsal root ganglia were studied in rat models of Diabetes mellitus type 1 (DM1) and type 2 (DM2). DM1 was induced with 55mg/kg streptozotocin, and DM2 with a combination of high-fat diet and 35mg/kg of streptozotocin. Pain-related behavior was analyzed using thermal and mechanical stimuli. The expression of CaMKII was analyzed with immunofluorescence. Sexual dimorphism in glycemia, and expression of CaMKII was observed in the rat model of DM1, but not in DM2 animals. Increased expression of total CaMKII (tCaMKII) in small-diameter dorsal root ganglia neurons, which are associated with nociception, was found only in male DM1 rats. None of the animals showed increased expression of the phosphorylated alpha CaMKII isoform in small-diameter neurons. The expression of gamma and delta isoforms of CaMKII remained unchanged in all analyzed animal groups. Different patterns of glycemia and tCaMKII expression in male and female model of DM1 were not associated with sexual dimorphism in pain-related behavior. The present findings do not suggest sex-related differences in diabetic painful peripheral neuropathy in male and female diabetic rats. Copyright © 2012 Elsevier GmbH. All rights reserved.

Markov-CA model using analytical hierarchy process and multiregression technique

International Nuclear Information System (INIS)

Omar, N Q; Sanusi, S A M; Hussin, W M W; Samat, N; Mohammed, K S

2014-01-01

The unprecedented increase in population and rapid rate of urbanisation has led to extensive land use changes. Cellular automata (CA) are increasingly used to simulate a variety of urban dynamics. This paper introduces a new CA based on an integration model built-in multi regression and multi-criteria evaluation to improve the representation of CA transition rule. This multi-criteria evaluation is implemented by utilising data relating to the environmental and socioeconomic factors in the study area in order to produce suitability maps (SMs) using an analytical hierarchical process, which is a well-known method. Before being integrated to generate suitability maps for the periods from 1984 to 2010 based on the different decision makings, which have become conditioned for the next step of CA generation. The suitability maps are compared in order to find the best maps based on the values of the root equation (R 2 ). This comparison can help the stakeholders make better decisions. Thus, the resultant suitability map derives a predefined transition rule for the last step for CA model. The approach used in this study highlights a mechanism for monitoring and evaluating land-use and land-cover changes in Kirkuk city, Iraq owing changes in the structures of governments, wars, and an economic blockade over the past decades. The present study asserts the high applicability and flexibility of Markov-CA model. The results have shown that the model and its interrelated concepts are performing rather well

Possible relationship between the stress-induced synaptic response and metaplasticity in the hippocampal CA1 field of freely moving rats.

Science.gov (United States)

Hirata, Riki; Matsumoto, Machiko; Judo, Chika; Yamaguchi, Taku; Izumi, Takeshi; Yoshioka, Mitsuhiro; Togashi, Hiroko

2009-07-01

Hippocampal long-term potentiation (LTP) is suppressed not only by stress paradigms but also by low frequency stimulation (LFS) prior to LTP-inducing high frequency stimulation (HFS; tetanus), termed metaplasticity. These synaptic responses are dependent on N-methyl-D-aspartate receptors, leading to speculations about the possible relationship between metaplasticity and stress-induced LTP impairment. However, the functional significance of metaplasticity has been unclear. The present study elucidated the electrophysiological and neurochemical profiles of metaplasticity in the hippocampal CA1 field, with a focus on the synaptic response induced by the emotional stress, contextual fear conditioning (CFC). The population spike amplitude in the CA1 field was decreased during exposure to CFC, and LTP induction was suppressed after CFC in conscious rats. The synaptic response induced by CFC was mimicked by LFS, i.e., LFS impaired the synaptic transmission and subsequent LTP. Plasma corticosterone levels were increased by both CFC and LFS. Extracellular levels of gamma-aminobutyric acid (GABA), but not glutamate, in the hippocampus increased during exposure to CFC or LFS. Furthermore, electrical stimulation of the medial prefrontal cortex (mPFC), which caused decreases in freezing behavior during exposure to CFC, counteracted the LTP impairment induced by LFS. These findings suggest that metaplasticity in the rat hippocampal CA1 field is related to the neural basis of stress experience-dependent fear memory, and that hippocampal synaptic response associated stress-related processes is under mPFC regulation.

Effect of MgSO4 on the contents of Ca2+ in brain cell and NO in brain tissue of rats with radiation-induced acute brain injury

International Nuclear Information System (INIS)

Yuan Wenjia; Cui Fengmei; Liu Ping; He Chao; Tu Yu; Wang Lili

2009-01-01

The work is to explore the protection of magnesium sulfate(MgSO 4 ) on radiation-induced acute brain injury. Thirty six mature Sprague-Dawley(SD) rats were randomly divided into 3 groups of control, experimental control and experimental therapy group. The whole brains of SD rats of experimental control and experimental therapy group were irradiated with a dose of 20 Gy using 6 MeV electron beam. MgSO 4 was injected into the abdomen of experimental therapy rats group 1 day before, immediately and continue for 5 days after irradiation respectively. The brain tissues were taken on 3, 10, 17 and 24 d after irradiation. Ca 2+ content in brain cell was measured by laser scanning confocal microscopy, and the NO content in brain tissue was detected by the method of nitric acid reductase. Compared with the blank control group, the contents of Ca 2+ in brain cell and NO in brain tissue of the experimental control group increase (P 4 used in early stage can inhibit the contents of Ca 2+ in brain cell and NO in brain tissue after radiation-induced acute brain injury. It means that MgSO 4 has a protective effect on radiation-induced acute brain injury. (authors)

Ethanol stimulates ROS generation by mitochondria through Ca2+ mobilization and increases GFAP content in rat hippocampal astrocytes.

Science.gov (United States)

González, Antonio; Pariente, José A; Salido, Ginés M

2007-10-31

We have employed rat hippocampal astrocytes in culture to investigate the effect of ethanol on reactive oxygen species (ROS) production as well as its effect on [Ca2+]c and GFAP expression. Cells were loaded with the fluorescent probes fura-2 and H2DCFDA for the determination of changes in [Ca2+]c and ROS production respectively, employing spectrofluorimetry. GFAP content was determined by immunocytochemistry and confocal scanning microscopy. Our results show ROS production in response to 50 mM ethanol, that was reduced in Ca2+-free medium (containing 0.5 mM EGTA) and in the presence of the intracellular Ca2+ chelator BAPTA (10 microM). The effect of ethanol on ROS production was significantly reduced in the presence of the alcohol dehydrogenase inhibitor 4-methylpyrazole (1 mM), and the antioxidants resveratrol (100 microM) or catalase (300 U/ml). Preincubation of astrocytes in the presence of 10 microM antimycin plus 10 microM oligomycin to inhibit mitochondria completely blocked ethanol-evoked ROS production. In addition, ethanol led to a sustained increase in [Ca2+]c that reached a constant level over the prestimulation values. Finally, incubation of astrocytes in the presence of ethanol increased the content of GFAP that was significantly reduced in the absence of extracellular Ca2+ and by resveratrol and catalase pretreatment. The data obtained in the present study suggest that astrocytes are able to metabolize ethanol, which induces two effects on intracellular homeostasis: an immediate response (Ca2+ release and ROS generation) and later changes involving GFAP expression. Both effects may underline various signaling pathways which are important for cell proliferation, differentiation and function.

Cardioprotection by controlling hyperamylinemia in a "humanized" diabetic rat model.

Science.gov (United States)

Despa, Sanda; Sharma, Savita; Harris, Todd R; Dong, Hua; Li, Ning; Chiamvimonvat, Nipavan; Taegtmeyer, Heinrich; Margulies, Kenneth B; Hammock, Bruce D; Despa, Florin

2014-08-21

Chronic hypersecretion of the pancreatic hormone amylin is common in humans with obesity or prediabetic insulin resistance and induces amylin aggregation and proteotoxicity in the pancreas. We recently showed that hyperamylinemia also affects the cardiovascular system. Here, we investigated whether amylin aggregates interact directly with cardiac myocytes and whether controlling hyperamylinemia protects the heart. By Western blot, we found abundant amylin aggregates in lysates of cardiac myocytes from obese patients, but not in controls. Aggregated amylin was elevated in failing hearts, suggesting a role in myocyte injury. Using rats overexpressing human amylin in the pancreas (HIP rats) and control myocytes incubated with human amylin, we show that amylin aggregation at the sarcolemma induces oxidative stress and Ca(2+) dysregulation. In time, HIP rats developed cardiac hypertrophy and left-ventricular dilation. We then tested whether metabolites with antiaggregation properties, such as eicosanoid acids, limit myocardial amylin deposition. Rats were treated with an inhibitor of soluble epoxide hydrolase, the enzyme that degrades endogenous eicosanoids. Treatment doubled the blood concentration of eicosanoids, which drastically reduced incorporation of aggregated amylin in cardiac myocytes and blood cells, without affecting pancreatic amylin secretion. Animals in the treated group showed reduced cardiac hypertrophy and left-ventricular dilation. The cardioprotective mechanisms included the mitigation of amylin-induced cardiac oxidative stress and Ca(2+) dysregulation. The results suggest blood amylin as a novel therapeutic target in diabetic heart disease and elevating blood levels of antiaggregation metabolites as a pharmacological strategy to reduce amylin aggregation and amylin-mediated cardiotoxicity. © 2014 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Cyanidin-3-glucoside inhibits glutamate-induced Zn2+ signaling and neuronal cell death in cultured rat hippocampal neurons by inhibiting Ca2+-induced mitochondrial depolarization and formation of reactive oxygen species.

Science.gov (United States)

Yang, Ji Seon; Perveen, Shazia; Ha, Tae Joung; Kim, Seong Yun; Yoon, Shin Hee

2015-05-05

Cyanidin-3-glucoside (C3G), a member of the anthocyanin family, is a potent natural antioxidant. However, effects of C3G on glutamate-induced [Zn(2+)]i increase and neuronal cell death remain unknown. We studied the effects of C3G on glutamate-induced [Zn(2+)]i increase and cell death in cultured rat hippocampal neurons from embryonic day 17 maternal Sprague-Dawley rats using digital imaging methods for Zn(2+), Ca(2+), reactive oxygen species (ROS), mitochondrial membrane potential and a MTT assay for cell survival. Treatment with glutamate (100 µM) for 7 min induces reproducible [Zn(2+)]i increase at 35 min interval in cultured rat hippocampal neurons. The intracellular Zn(2+)-chelator TPEN markedly blocked glutamate-induced [Zn(2+)]i increase, but the extracellular Zn(2+) chelator CaEDTA did not affect glutamate-induced [Zn(2+)]i increase. C3G inhibited the glutamate-induced [Zn(2+)]i response in a concentration-dependent manner (IC50 of 14.1 ± 1.1 µg/ml). C3G also significantly inhibited glutamate-induced [Ca(2+)]i increase. Two antioxidants such as Trolox and DTT significantly inhibited the glutamate-induced [Zn(2+)]i response, but they did not affect the [Ca(2+)]i responses. C3G blocked glutamate-induced formation of ROS. Trolox and DTT also inhibited the formation of ROS. C3G significantly inhibited glutamate-induced mitochondrial depolarization. However, TPEN, Trolox and DTT did not affect the mitochondrial depolarization. C3G, Trolox and DTT attenuated glutamate-induced neuronal cell death in cultured rat hippocampal neurons, respectively. Taken together, all these results suggest that cyanidin-3-glucoside inhibits glutamate-induced [Zn(2+)]i increase through a release of Zn(2+) from intracellular sources in cultured rat hippocampal neurons by inhibiting Ca(2+)-induced mitochondrial depolarization and formation of ROS, which is involved in neuroprotection against glutamate-induced cell death. Copyright © 2015 Elsevier B.V. All rights reserved.

Depression of calcium pump activity in renal cortex of vitamin D-deficient rats with secondary hyperparathyroidism

International Nuclear Information System (INIS)

Tsukamoto, Yusuke; Saitoh, Michiyo; Takita, Yumiko; Nakano, Toshiaki; Tamura, Teiichi

1990-01-01

To examine the hormonal regulation of the ATP-dependent Ca 2+ pump in the kidneys, the ATP-dependent Ca 2+ uptake by the basolateral membrane vesicles in the renal cortex was measured using radioactive calcium ( 45 Ca 2+ ) in rats with vitamin D deficiency or rats undergoing thyroparathyroidectomy. The V max of the Ca 2+ pump activity was increased not only by administering calcitriol, but also by normalizing the serum calcium level in vitamin D-deficient rats. PTH suppressed the Ca 2+ pump activity in normocalcemic vitamin D-deficient rats. Thyroparathyroidectomy did not affect the Ca 2+ pump activity in the kidneys of normal rats. It was concluded that the ATP-dependent Ca 2+ pump activity was depressed by secondary hyperparathyroidism in vitamin D-deficient rats. (author)

DDPH ameliorated oxygen and glucose deprivation-induced injury in rat hippocampal neurons via interrupting Ca2+ overload and glutamate release.

Science.gov (United States)

He, Zhi; Lu, Qing; Xu, Xulin; Huang, Lin; Chen, Jianguo; Guo, Lianjun

2009-01-28

Our previous work has demonstrated that DDPH (1-(2, 6-dimethylphenoxy)-2-(3, 4-dimethoxyphenylethylamino) propane hydrochloride), a competitive alpha(1)-adrenoceptor antagonist, could improve cognitive deficits, reduce histopathological damage and facilitate synaptic plasticity in vivo possibly via increasing NR2B (NMDA receptor 2B) expression and antioxidation of DDPH itself. The present study further evaluated effects of DDPH on OGD (Oxygen and glucose deprivation)-induced neuronal damage in rat primary hippocampal cells. The addition of DDPH to the cultured cells 12 h before OGD for 4 h significantly reduced neuronal damage as determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and LDH (lactate dehydrogenase) release experiments. The effects of DDPH on intracellular calcium concentration were explored by Fura-2 based calcium imaging techniques and results showed that DDPH at the dosages of 5 microM and 10 microM suppressed the increase of intracellular calcium ([Ca(2+)](i)) stimulated by 50 mM KCl in Ca(2+)-containing extracellular solutions. However, DDPH couldn't suppress the increase of [Ca(2+)](i) induced by both 50 microM glutamate in Ca(2+)-containing extracellular solutions and 20 microM ATP (Adenosine Triphosphate) in Ca(2+)-free solution. These results indicated that DDPH prevented [Ca(2+)](i) overload in hippocampal neurons by blocking Ca(2+) influx (voltage-dependent calcium channel) but not Ca(2+) mobilization from the intracellular Ca(2+) store in endoplasm reticulum (ER). We also demonstrated that DDPH could decrease glutamate release when hippocampal cells were subjected to OGD. These observations demonstrated that DDPH protected hippocampal neurons against OGD-induced damage by preventing the Ca(2+) influx and decreasing glutamate release.

Hippocampal astrocytes are necessary for antidepressant treatment of learned helplessness rats.

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Iwata, Masaaki; Shirayama, Yukihiko; Ishida, Hisahito; Hazama, Gen-i; Nakagome, Kazuyuki

2011-08-01

The astrocyte is a major component of the neural network and plays a role in brain function. Previous studies demonstrated changes in the number of astrocytes in depression. In this study, we examined alterations in the number of astrocytes in the learned helplessness (LH) rat, an animal model of depression. The numbers of activated and nonactivated astrocytes in the dentate gyrus (molecular layer, subgranular zone, and hilus), and CA1 and CA3 regions of the hippocampus were significantly increased 2 and 8 days after attainment of LH. Subchronic treatment with imipramine showed a tendency (although not statistically significant) to decrease the LH-induced increment of activated astrocytes in the CA3 region and dentate gyrus. Furthermore, subchronic treatment of naïve rats with imipramine did not alter the numbers of activated and nonactivated astrocytes. However, the antidepressant-like effects of imipramine in the LH paradigm were blocked when fluorocitrate (a reversible inhibitor of astrocyte function) was injected into the dentate gyrus or CA3 region. Injection of fluorocitrate into naive rats failed to induce behavioral deficits in the conditioned avoidance test. These results indicate that astrocytes are responsive to the antidepressant-like effect of imipramine in the dentate gyrus and CA3 region of the hippocampus. Copyright © 2010 Wiley-Liss, Inc.

A potential kidney-bone axis involved in the rapid minute-to-minute regulation of plasma Ca2+

DEFF Research Database (Denmark)

Nordholm, Anders; Mace, Maria L; Gravesen, Eva

2015-01-01

, as induced by total bilateral nephrectomy and to study the effect of absence of kidneys on the rapid recovery of p-Ca(2+) from a brief induction of acute hypocalcemia. METHODS: The rapid regulation of p-Ca(2+) was examined in sham-operated rats, acute nephrectomized rats (NX), acute thyroparathyrectomized......(TPTX) rats and NX-TPTX rats. RESULTS: The results clearly showed that p-Ca(2+) falls rapidly and significantly very early after acute NX, from 1.23 ± 0.02 to 1.06 ± 0.04 mM (p hypocalcemia was induced by a 30 min iv infusion of EGTA. Control groups had saline. After discontinuing EGTA...... a rapid increase in p-Ca(2+) took place, but with a lower level in NX rats (p effect of accumulation of Calcitonin and C-terminal PTH, both having potential hypocalcemic actions. Acute TPTX resulted in hypercalcemia, 1.44 ± 0.02 mM and less in NX-TPTX rats,1...

Alterations in brain-derived neurotrophic factor (BDNF) and its precursor proBDNF in the brain regions of a learned helplessness rat model and the antidepressant effects of a TrkB agonist and antagonist.

Science.gov (United States)

Shirayama, Yukihiko; Yang, Chun; Zhang, Ji-chun; Ren, Qian; Yao, Wei; Hashimoto, Kenji

2015-12-01

Role of brain-derived neurotrophic factor (BDNF)-TrkB signaling in a learned helplessness (LH) model of depression was investigated. LH rats showed a reduction of BDNF in the medial prefrontal cortex (mPFC), CA3, and dentate gyrus (DG) of the hippocampus, whereas LH rats showed an increase in BDNF in the nucleus accumbens (NAc). Furthermore, levels of proBDNF, a BDNF precursor, were higher in the mPFC, but lower in the NAc, of LH rats. A single bilateral infusion of a TrkB agonist 7,8-DHF, but not a TrkB antagonist ANA-12, into the infralimbic (IL) of mPFC, DG, and CA3, but not the prelimbic (PrL) of mPFC, exerted antidepressant effects in LH rats. In contrast, a single bilateral infusion of ANA-12, but not 7,8-DHF, into the core and shell of NAc exerted antidepressant-like effects in LH rats, with more potent effects observed for the NAc core than for NAc shell. Interestingly, a single administration of 7,8-DHF (10mg/kg, i.p.) significantly improved a decreased phosphorylation of TrkB in the mPFC, CA3, and DG of LH rats. Additionally, ANA-12 (0.5mg/kg, i.p.) significantly improved an increased phosphorylation of TrkB in the NAc of LH rats. In conclusion, these results suggest that LH causes depression-like behavior by altering BDNF in the brain regions, and that proBDNF-BDNF processing and transport may be altered in the mPFC-NAc circuit of LH rats. Therefore, TrkB agonists might exert antidepressant effects by stimulating TrkB in the IL, CA3, and DG, while TrkB antagonists might exert antidepressant effects by blocking TrkB in the NAc. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

Exendin-4 Plays a Protective Role in a Rat Model of Spinal Cord Injury Through SERCA2

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Zhonglei Sun

2018-05-01

Full Text Available Background/Aims: Current therapies for spinal cord injury (SCI have limited efficacy, and identifying a therapeutic target is a pressing need. Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2 plays an important role in regulating calcium homeostasis, which has been shown to inhibit apoptosis. Exendin-4 has been shown to inhibit the apoptosis of nerve cells in SCI, which can also improve SERCA2 expression. In this study, we sought to determine whether exendin-4 plays a protective role in a rat model of SCI via SERCA2. Methods: To investigate the effects of exendin-4 on SCI, a rat model of SCI was induced by a modified version of Allen’s method. Spinal cord tissue sections from rats and western blot analysis were used to examine SERCA2 expression after treatment with the long-acting glucagon-like peptide 1 receptor exendin-4 or the SERCA2 antagonist 5(6-carboxyfluorescein diacetate N-succinimidyl ester (CE. Locomotor function was evaluated using the Basso Beattie Bresnahan locomotor rating scale and slanting board test. Results: Cell apoptosis was increased with CE treatment and decreased with exendin-4 treatment. Upregulation of SERCA2 in female rats with SCI resulted in an improvement of motor function scores and histological changes. Conclusion: These findings suggest that exendin-4 plays a protective role in a rat model of SCI through SERCA2 via inhibition of apoptosis. Existing drugs targeting SERCA2 may be an effective therapeutic strategy for the treatment of SCI.

The GLP-1 Receptor Agonist Exendin-4 and Diazepam Differentially Regulate GABAA Receptor-Mediated Tonic Currents in Rat Hippocampal CA3 Pyramidal Neurons.

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Sergiy V Korol

Full Text Available Glucagon-like peptide-1 (GLP-1 is a metabolic hormone that is secreted in a glucose-dependent manner and enhances insulin secretion. GLP-1 receptors are also found in the brain where their signalling affects neuronal activity. We have previously shown that the GLP-1 receptor agonists, GLP-1 and exendin-4 enhanced GABA-activated synaptic and tonic currents in rat hippocampal CA3 pyramidal neurons. The hippocampus is the centre for memory and learning and is important for cognition. Here we examined if exendin-4 similarly enhanced the GABA-activated currents in the presence of the benzodiazepine diazepam. In whole-cell recordings in rat brain slices, diazepam (1 μM, an allosteric positive modulator of GABAA receptors, alone enhanced the spontaneous inhibitory postsynaptic current (sIPSC amplitude and frequency by a factor of 1.3 and 1.6, respectively, and doubled the tonic GABAA current normally recorded in the CA3 pyramidal cells. Importantly, in the presence of exendin-4 (10 nM plus diazepam (1 μM, only the tonic but not the sIPSC currents transiently increased as compared to currents recorded in the presence of diazepam alone. The results suggest that exendin-4 potentiates a subpopulation of extrasynaptic GABAA receptors in the CA3 pyramidal neurons.

Modeling the Onset of Phase Separation in CaO-SiO2-CaCl2 Chlorine-Containing Silicate Glasses.

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Swansbury, Laura A; Mountjoy, Gavin; Chen, Xiaojing; Karpukhina, Natalia; Hill, Robert

2017-06-08

The addition of chlorine into a bioactive glass composition is expected to reduce its abrasiveness and increase its bioactivity, which is important for dental applications such as toothpastes. There is a lack of information and understanding regarding the structural role of chlorine in chlorine-containing bioactive silicate glasses. This has prompted classical core-shell model molecular dynamics simulations of (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses to be performed, where x ranges from x = 0.0 to 43.1 mol % CaCl 2 . These ternary glasses are advantageous for a fundamental study because they do not have additional network formers (e.g., phosphorus pentoxide) or modifiers (e.g., sodium) typically found in bioactive glass compositions. The (50 - x/2)CaO-(50 - x/2)SiO 2 -xCaCl 2 glasses were seen to become phase-separated around the x = 16.1 mol % CaCl 2 composition, and chlorine predominantly coordinated with calcium. These findings provide a solid foundation for further computational modeling work on more complex chlorine-containing bioactive glass compositions.

Neuropathological Changes in Brain Cortex and Hippocampus in a Rat Model of Alzheimer’s Disease

Science.gov (United States)

Nobakht, Maliheh; Hoseini, Seyed Mohammad; Mortazavi, Pejman; Sohrabi, Iraj; Esmailzade, Banafshe; Roosh, Nahid Rahbar; Omidzahir, Shila

2011-01-01

Background: Alzheimer’s disease (AD) is a neurodegenerative disorder with progressive loss of cognitive abilities and memory loss. The aim of this study was to compare neuropathological changes in hippocampus and brain cortex in a rat model of AD. Methods: Adult male Albino Wistar rats (weighing 250-300 g) were used for behavioral and histopathological studies. The rats were randomly assigned to three groups: control, sham and β-amyloid (Aβ) injection. For behavioral analysis, Y-maze and shuttle box were used, respectively at 14 and 16 days post-lesion. For histological studies, Nissl, modified Bielschowsky and modified Congo red staining were performed. The lesion was induced by injection of 4 µL of Aβ (1-40) into the hippocampal fissure. Results: In the present study, Aβ (1-40) injection into hippocampus could decrease the behavioral indexes and the number of CA1 neurons in hippocampus. Aβ injection CA1 caused Aβ deposition in the hippocampus and less than in cortex. We observed the loss of neurons in the hippocampus and cerebral cortex and certain subcortical regions. Y-maze test and single-trial passive avoidance test showed reduced memory retention in AD group. Conclusion: We found a significant decreased acquisition of passive avoidance and alternation behavior responses in AD group compared to control and sham group (P<0.0001). Compacted amyloid cores were present in the cerebral cortex, hippocampus and white matter, whereas, scattered amyloid cores were seen in cortex and hippocampus of AD group. Also, reduced neuronal density was indicated in AD group. PMID:21725500

Nicardipine reduces calcium accumulation and electrolyte derangements in regional cerebral ischemia in rats

International Nuclear Information System (INIS)

Hadani, M.; Young, W.; Flamm, E.S.

1988-01-01

We studied the effects of the calcium channel blocker nicardipine on regional tissue Ca 2+ , Na + , K + , and water shifts in the brains of seven Sprague-Dawley rats after permanent occlusions of the middle cerebral artery. We also assessed the entry of [ 14 C]nicardipine into the brains of five rats; the highest concentrations of [ 14 C]nicardipine were in the infarcted area. Nicardipine treatment significantly reduced Ca 2+ accumulation in the middle cerebral artery territory by 60% compared with six untreated rats 6 hours after arterial occlusion. Eight 125-micrograms/kg boluses of nicardipine given every 30 minutes starting 5 minutes after arterial occlusion also significantly reduced the Na + and K + shifts in the middle cerebral artery territory by 40% and 50%, respectively, 6 hours after arterial occlusion. Nicardipine appears to reduce Ca 2+ accumulation more than it reduces Na + and water accumulation and K + loss. Our results suggest that a calcium channel blocker can protect brain tissues in a model of focal cerebral infarction by directly reducing Ca 2+ entry into ischemic cells

Polyamines mediate abnormal Ca2+ transport and Ca2+-induced cardiac cell injury in the calcium paradox

International Nuclear Information System (INIS)

Trout, J.J.; Koenig, H.; Goldstone, A.D.; Lu, C.Y.; Fan, C.C.

1986-01-01

Ca 2+ -free perfusion renders heart cells Ca 2+ -sensitive so that readmission of Ca 2+ causes a sudden massive cellular injury attributed to abnormal entry of Ca 2+ into cells (Ca paradox). Hormonal stimulation of Ca 2+ fluxes was earlier shown to be mediated by polyamines (PA). 5 min perfusion of rat heart with Ca 2+ -free medium induce a prompt 40-50% decline in levels of the PA putrescine (PUT), spermidine and spermine and their rate-regulatory synthetic enzyme ornithine decarboxylase (ODC), and readmission of Ca 2+ -containing medium abruptly ( 2+ reperfusion-induced increases in ODC and PA and also prevented increased 45 Ca 2+ uptake and heart injury, manifested by loss of contractility, release of enzymes (CPK, LDH), myoglobin and protein, and E.M. lesions (contracture bands, mitochondrial changes). 1 mM PUT negated DFMO inhibition, repleted heart PA and restored Ca 2+ reperfusion-induced 45 Ca 2+ influx and cell injury. These data indicate that the Ca 2+ -directed depletion-repletion cycle of ODC and PA triggers excessive transsarcolemmal Ca 2+ transport leading to the calcium paradox

Oxidized CaMKII (Ca2+/Calmodulin-Dependent Protein Kinase II) Is Essential for Ventricular Arrhythmia in a Mouse Model of Duchenne Muscular Dystrophy.

Science.gov (United States)

Wang, Qiongling; Quick, Ann P; Cao, Shuyi; Reynolds, Julia; Chiang, David Y; Beavers, David; Li, Na; Wang, Guoliang; Rodney, George G; Anderson, Mark E; Wehrens, Xander H T

2018-04-01

Duchenne muscular dystrophy patients are prone to ventricular arrhythmias, which may be caused by abnormal calcium (Ca 2+ ) homeostasis and elevated reactive oxygen species. CaMKII (Ca 2+ /calmodulin-dependent protein kinase II) is vital for normal Ca 2+ homeostasis, but excessive CaMKII activity contributes to abnormal Ca 2+ homeostasis and arrhythmias in cardiomyocytes. Reactive oxygen species induce CaMKII to become autonomously active. We hypothesized that genetic inhibition of CaMKII oxidation (ox-CaMKII) in a mouse model of Duchenne muscular dystrophy can alleviate abnormal Ca 2+ homeostasis, thus, preventing ventricular arrhythmia. The objective of this study was to test if selective loss of ox-CaMKII affects ventricular arrhythmias in the mdx mouse model of Duchenne muscular dystrophy. 5-(6)-Chloromethyl-2,7-dichlorodihydrofluorescein diacetate staining revealed increased reactive oxygen species production in ventricular myocytes isolated from mdx mice, which coincides with elevated ventricular ox-CaMKII demonstrated by Western blotting. Genetic inhibition of ox-CaMKII by knockin replacement of the regulatory domain methionines with valines (MM-VV [CaMKII M281/282V]) prevented ventricular tachycardia in mdx mice. Confocal calcium imaging of ventricular myocytes isolated from mdx :MM-VV mice revealed normalization of intracellular Ca 2+ release events compared with cardiomyocytes from mdx mice. Abnormal action potentials assessed by optical mapping in mdx mice were also alleviated by genetic inhibition of ox-CaMKII. Knockout of the NADPH oxidase regulatory subunit p47 phox normalized elevated ox-CaMKII, repaired intracellular Ca 2+ homeostasis, and rescued inducible ventricular arrhythmias in mdx mice. Inhibition of reactive oxygen species or ox-CaMKII protects against proarrhythmic intracellular Ca 2+ handling and prevents ventricular arrhythmia in a mouse model of Duchenne muscular dystrophy. © 2018 American Heart Association, Inc.

Involvement of N-methyl-D-aspartate receptor subunits in zinc-mediated modification of CA1 long-term potentiation in the developing hippocampus.

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Takeda, Atsushi; Itagaki, Kosuke; Ando, Masaki; Oku, Naoto

2012-03-01

Zinc is an endogenous N-methyl-D-aspartate (NMDA) receptor blocker. It is possible that zinc-mediated modification of hippocampal CA1 long-term potentiation (LTP) is linked to the expression of NMDA receptor subunits, which varies with postnatal development. In the present study, the effect of ZnCl(2) and CaEDTA, a membrane-impermeable zinc chelator, on CA1 LTP induction was examined in hippocampal slices from immature (3-week-old) and young (6-week-old) rats. Tetanus (10-100 Hz, 1 sec)-induced CA1 LTP was more greatly enhanced in 3-week-old rats. CA1 LTP was inhibited in the presence of 2-amino-5-phosphonovalerate (APV), an NMDA receptor antagonist, and CaEDTA in 3-week-old rats, as in the case of 6-week-old rats reported previously. In 3-week-old rats, on the other hand, 5 μM ZnCl(2) attenuated NMDA receptor-mediated EPSPs more than in 6-week-old rats and significantly attenuated CA1 LTP. Moreover, 5 μM ZnCl(2) significantly attenuated CA1 LTP in the presence of (2R,4S)-4-(3-phosphonopropyl)-2-piperidinecarboxylic acid (PPPA), an NR2A antagonist, in 3-week-old rats, but not that in the presence of ifenprodil, an NR2B antagonist, suggesting that zinc-mediated attenuation of CA1 LTP is associated with the preferential expression of NR2B subunit in 3-week-old rats. In 6-week-old rats, however, 5 μM ZnCl(2) significantly potentiated CA1 LTP and also CA1 LTP in the presence of PPPA. The present study demonstrates that endogenous zinc may participate in the induction of CA1 LTP. It is likely that the changes in expression of NMDA receptor subunits are involved in the zinc-mediated modification of CA1 LTP in the developing hippocampus. Copyright © 2011 Wiley Periodicals, Inc.

ENU mutagenesis to generate genetically modified rat models.

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van Boxtel, Ruben; Gould, Michael N; Cuppen, Edwin; Smits, Bart M G

2010-01-01

The rat is one of the most preferred model organisms in biomedical research and has been extremely useful for linking physiology and pathology to the genome. However, approaches to genetically modify specific genes in the rat germ line remain relatively scarce. To date, the most efficient approach for generating genetically modified rats has been the target-selected N-ethyl-N-nitrosourea (ENU) mutagenesis-based technology. Here, we describe the detailed protocols for ENU mutagenesis and mutant retrieval in the rat model organism.

Stereological brain volume changes in post-weaned socially isolated rats

DEFF Research Database (Denmark)

Fabricius, Katrine; Helboe, Lone; Steiniger-Brach, Björn

2010-01-01

Lister Hooded rats isolated from postnatal day 25 for 15 weeks. We observed the expected gender differences in total brain volume with males having larger brains than females. Further, we found that isolated males had significantly smaller brains than group-housed controls and larger lateral ventricles...... have evaluated the neuroanatomical changes in this animal model in comparison to changes seen in schizophrenia. In this study, we applied stereological volume estimates to evaluate the total brain, the ventricular system, and the pyramidal and granular cell layers of the hippocampus in male and female...... than controls. However, this was not seen in female rats. Isolated males had a significant smaller hippocampus, dentate gyrus and CA2/3 where isolated females had a significant smaller CA1 compared to controls. Thus, our results indicate that long-term isolation of male rats leads to neuroanatomical...

Oxidative stress of crystalline lens in rat menopausal model

OpenAIRE

Acer, Semra; Pekel, Gökhan; Küçükatay, Vural; Karabulut, Aysun; Yağcı, Ramazan; Çetin, Ebru Nevin; Akyer, Şahika Pınar; Şahin, Barbaros

2016-01-01

ABSTRACT Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Gro...

Changes in the content of fatty acids in CA1 and CA3 areas of the hippocampus of Krushinsky-Molodkina rats after single and fivefold audiogenic seizures.

Science.gov (United States)

Savina, Tatyana; Aripovsky, Alexander; Kulagina, Tatyana

2017-09-01

Audiogenic seizures (AS) are generalized seizures evoked by high frequency sounds. Since the hippocampus is involved in the generation and maintenance of seizures, the effect of AS on the composition and content of fatty acids in the CA1 and CA3 hippocampal areas of AS-susceptible Krushinsky-Molodkina (KM) rats on days 1, 3, and 14 after single and fivefold seizures were examined. The total content of all fatty acids in field СА1 was found to be lower compared with the control at all times of observation after both a single seizure or fivefold seizures. The total content of fatty acids in field СА3 decreased at all times of examination after a single seizure, whereas it remained unchanged on days 3 and 14 following five AS. The content of omega-3 fatty acids in both fields at all times of observation after a single seizure and fivefold AS did not significantly differ from that in intact animals. The absence of significant changes in the content of stearic and α-linolenic acids and a considerable decrease in the levels of palmitic, oleic, and eicosapentaenoic acids were common to both fields at all times after both a single seizure or fivefold AS. The changes in the content of fatty acids in the СА3 and СА1 fields of the brain of AS-susceptible rats indicate that fatty acids are involved in both the development of seizure activity and neuroprotective anticonvulsive processes. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of potato on acid-base and mineral homeostasis in rats fed a high-sodium chloride diet.

Science.gov (United States)

Narcy, Agnès; Robert, Laetitia; Mazur, Andrzej; Demigné, Christian; Rémésy, Christian

2006-05-01

Excessive dietary NaCl in association with a paucity of plant foods, major sources of K alkaline salts, is a common feature in Western eating habits which may lead to acid-base disorders and to Ca and Mg wasting. In this context, to evaluate the effects of potato, rich in potassium citrate, on acid-base homeostasis and mineral retention, Wistar rats were fed wheat starch (WS) or cooked potato (CP) diets with a low (0.5 %) or a high (2 %) NaCl content during 3 weeks. The replacement of WS by CP in the diets resulted in a significant urinary alkalinisation (pH from 5.5 to 7.3) parallel to a rise in citrate and K excretion. Urinary Ca and Mg elimination represented respectively 17 and 62 % of the daily absorbed mineral in rats fed the high-salt WS diet compared with 5 and 28 % in rats fed the high-salt CP diet. The total SCFA concentration in the caecum was 3-fold higher in rats fed the CP diets compared with rats fed the WS diets, and it led to a significant rise in Ca and Mg intestinal absorption (Ca from 39 to 56 %; Mg from 37 to 60 %). The present model of low-grade metabolic acidosis indicates that CP may be effective in alkalinising urine, enhancing citrate excretion and ameliorating Ca and Mg balance.

Streptozotocin Inhibits Electrophysiological Determinants of Excitatory and Inhibitory Synaptic Transmission in CA1 Pyramidal Neurons of Rat Hippocampal Slices: Reduction of These Effects by Edaravone

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Ting Ju

2016-12-01

Full Text Available Background: Streptozotocin (STZ has served as an agent to generate an Alzheimer's disease (AD model in rats, while edaravone (EDA, a novel free radical scavenger, has recently emerged as an effective treatment for use in vivo and vitro AD models. However, to date, these beneficial effects of EDA have only been clearly demonstrated within STZ-induced animal models of AD and in cell models of AD. A better understanding of the mechanisms of EDA may provide the opportunity for their clinical application in the treatment of AD. Therefore, the purpose of this study was to investigate the underlying mechanisms of STZ and EDA as assessed upon electrophysiological alterations in CA1 pyramidal neurons of rat hippocampal slices. Methods: Through measures of evoked excitatory postsynaptic currents (eEPSCs, AMPAR-mediated eEPSCs (eEPSCsAMPA, evoked inhibitory postsynaptic currents (eIPSCs, evoked excitatory postsynaptic current paired pulse ratio (eEPSC PPR and evoked inhibitory postsynaptic current paired pulse ratio (eIPSC PPR, it was possible to investigate mechanisms as related to the neurotoxicity of STZ and reductions in these effects by EDA. Results: Our results showed that STZ (1000 µM significantly inhibited peak amplitudes of eEPSCs, eEPSCsAMPA and eIPSCs, while EDA (1000 µM attenuated these STZ-induced changes at holding potentials ranging from -60mV to +40 mV for EPSCs and -60mV to +20 mV for IPSCs. Our work also indicated that mean eEPSC PPR were substantially altered by STZ, effects which were partially restored by EDA. In contrast, no significant effects upon eIPSC PPR were obtained in response to STZ and EDA. Conclusion: Our data suggest that STZ inhibits glutamatergic transmission involving pre-synaptic mechanisms and AMPAR, and that STZ inhibits GABAergic transmission by post-synaptic mechanisms within CA1 pyramidal neurons. These effects are attenuated by EDA.

Inositol 1,4,5-trisphosphate-sensitive Ca2+ release in rat fast- and slow-twitch skinned muscle fibres.

Science.gov (United States)

Talon, S; Huchet-Cadiou, C; Léoty, C

1999-11-01

Inositol 1,4,5-trisphosphate (InsP3), an intracellular messenger, induces Ca2+ release in various types of cells, particularly smooth muscle cells. Its role in skeletal muscle, however, is controversial. The present study shows that the application of InsP3 to rat slow- and fast-twitch saponin-skinned fibres induced contractile responses that were not related to an effect of InsP3 on the properties of the contractile proteins. The amplitude of the contractures was dependent upon the Ca(2+)-loading period, and was larger in slow- than in fast-twitch muscle. In both types of skeletal muscle, these responses, unlike caffeine contractures, were not inhibited by ryanodine (100 microM), but were abolished by heparin (20 micrograms.ml-1). In soleus muscle, the concentration of heparin required to inhibit the response by 50% (IC50) was 5.7 micrograms.ml-1, a similar value to that obtained previously in smooth muscle. Furthermore, the results show that in slow-twitch muscle, the InsP3 contractures have a "bell-shaped" dependency on the intracellular Ca2+ concentration. These results show that InsP3 receptors should be present in skeletal muscle. Thus, it is possible that InsP3 participates in the regulation of sarcoplasmic reticulum Ca2+ release in skeletal muscle, particularly in slow-twitch fibres.

Vitamin D-dependent rat renal calcium-binding protein: development of a radioimmunoassay, tissue distribution, and immunologic identification

International Nuclear Information System (INIS)

Sonnenberg, J.; Pansini, A.R.; Christakos, S.

1984-01-01

A sensitive double antibody RIA has been developed for the 28,000 mol wt rat renal vitamin D-dependent calcium-binding protein. Using this assay, concentrations of calcium-binding protein (CaBP) as low as 30 ng can be measured. The assay is precise (intraassay variability, 5.0%) and reproductible (interassay variability, 8.2%). Measurements of renal CaBP by RIA showed a good correlation with measurements of CaBP by the chelex resin assay and by polyacrylamide gel analysis by densitometric tracing using a purified CaBP marker. The concentration of CaBP in the vitamin D-replete rat kidney is 7.3 +/- 1.0 (mean +/- SEM) micrograms/mg protein. In vitamin D-deficient rats the level of renal CaBP is 2.6 +/- 0.3 micrograms/mg protein. Tissue distribution of immunoreactive rat renal CaBP showed the highest concentration of CaBP in the rat cerebellum (38.3 +/- 5.1 micrograms/mg protein). Lower concentrations of immunoreactive CaBP were detected in several other rat tissues. No immunoreactive CaBP was detected in rat or human serum. In necropsy human kidney and cerebellum, high levels of immunoreactive CaBP were also detected (1.5 +/- 0.1 and 27.3 +/- 2.1 micrograms/mg protein, respectively). When extracts of rat kidney and brain and human cerebellum and kidney were assayed at several dilutions, immunodisplacement curves parallel to that of pure renal CaBP were observed, indicating immunochemical similarity. Fractionation of extracts of rat cerebellum, human kidney, and human cerebellum on Sephadex G-100 revealed immunoreactivity and calcium-binding activity in the 28,000 mol wt region similar to rat kidney

Estrogen induces rapid decrease in dendritic thorns of CA3 pyramidal neurons in adult male rat hippocampus

International Nuclear Information System (INIS)

Tsurugizawa, Tomokazu; Mukai, Hideo

2005-01-01

Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. Here we demonstrated the rapid effect of estradiol on the density of thorns of thorny excrescences, by imaging Lucifer Yellow-injected CA3 neurons in adult male rat hippocampal slices. The application of 1 nM estradiol induced rapid decrease in the density of thorns on pyramidal neurons within 2 h. The estradiol-mediated decrease in the density of thorns was blocked by CNQX (AMPA receptor antagonist) and PD98059 (MAP kinase inhibitor), but not by MK-801 (NMDA receptor antagonist). ERα agonist PPT induced the same suppressive effect as that induced by estradiol on the density of thorns, but ERβ agonist DPN did not affect the density of thorns. Note that a 1 nM estradiol treatment did not affect the density of spines in the stratum radiatum and stratum oriens. A search for synaptic ERα was performed using purified RC-19 antibody. The localization of ERα (67 kDa) in the CA3 mossy fiber terminals and thorns was demonstrated using immunogold electron microscopy. These results imply that estradiol drives the signaling pathway including ERα and MAP kinase

Inhibition of small-conductance Ca2+-activated K+ channels terminates and protects against atrial fibrillation

DEFF Research Database (Denmark)

Diness, Jonas Goldin; Sørensen, Ulrik S; Nissen, Jakob Dahl

2010-01-01

Recently, evidence has emerged that small-conductance Ca(2+)-activated K(+) (SK) channels are predominantly expressed in the atria in a number of species including human. In rat, guinea pig, and rabbit ex vivo and in vivo models of atrial fibrillation (AF), we used 3 different SK channel inhibito...

Store-operated Ca2+ Entry Mediated by Orai1 and TRPC1 Participates to Insulin Secretion in Rat β-Cells*

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Sabourin, Jessica; Le Gal, Loïc; Saurwein, Lisa; Haefliger, Jacques-Antoine; Raddatz, Eric; Allagnat, Florent

2015-01-01

Store-operated Ca2+ channels (SOCs) are voltage-independent Ca2+ channels activated upon depletion of the endoplasmic reticulum Ca2+ stores. Early studies suggest the contribution of such channels to Ca2+ homeostasis in insulin-secreting pancreatic β-cells. However, their composition and contribution to glucose-stimulated insulin secretion (GSIS) remains unclear. In this study, endoplasmic reticulum Ca2+ depletion triggered by acetylcholine (ACh) or thapsigargin stimulated the formation of a ternary complex composed of Orai1, TRPC1, and STIM1, the key proteins involved in the formation of SOCs. Ca2+ imaging further revealed that Orai1 and TRPC1 are required to form functional SOCs and that these channels are activated by STIM1 in response to thapsigargin or ACh. Pharmacological SOCs inhibition or dominant negative blockade of Orai1 or TRPC1 using the specific pore mutants Orai1-E106D and TRPC1-F562A impaired GSIS in rat β-cells and fully blocked the potentiating effect of ACh on secretion. In contrast, pharmacological or dominant negative blockade of TRPC3 had no effect on extracellular Ca2+ entry and GSIS. Finally, we observed that prolonged exposure to supraphysiological glucose concentration impaired SOCs function without altering the expression levels of STIM1, Orai1, and TRPC1. We conclude that Orai1 and TRPC1, which form SOCs regulated by STIM1, play a key role in the effect of ACh on GSIS, a process that may be impaired in type 2 diabetes. PMID:26494622

Ca(2+)-dependent nonspecific permeability of the inner membrane of liver mitochondria in the guinea fowl (Numida meleagris).

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Vedernikov, Aleksander A; Dubinin, Mikhail V; Zabiakin, Vladimir A; Samartsev, Victor N

2015-06-01

This comparative study presents the results of the induction of Ca(2+)-dependent nonspecific permeability of the inner membrane (pore opening) of rat and guinea fowl liver mitochondria by mechanisms that are both sensitive and insensitive to cyclosporin A (CsA). It was established that energized rat and guinea fowl liver mitochondria incubated with 1 mM of inorganic phosphate (Pi) are capable of swelling upon addition of at least 125 and 875 nmol of CaCl2 per 1 mg protein, respectively. Under these conditions, the Ca(2+) release from the mitochondria of these animals and a drop in Δψ are observed. All of these processes are inhibited by 1 μM of CsA. FCCP, causing organelle de-energization, induces pore opening in rat and guinea fowl liver mitochondria upon addition of 45 и 625 nmol of CaCl2 per 1 mg protein, respectively. These results suggest the existence of a CsA-sensitive mechanism for the induction of Ca(2+)-dependent pores in guinea fowl liver mitochondria, which has been reported in rat liver mitochondria. However, guinea fowl liver mitochondria have a significantly greater resistance to Ca(2+) as a pore inducer compared to rat liver mitochondria. It was found that the addition of α,ω-hexadecanedioic acid (HDA) to rat and guinea fowl liver mitochondria incubated with CsA and loaded with Ca(2+) causes organelle swelling and Ca(2+) release from the matrix. It is assumed that in contrast to the CsA-sensitive pore, the CsA-insensitive pore induced by HDA in the inner membrane of guinea fowl liver mitochondria, as well as in rat liver mitochondria, is lipid in nature.

2,5-hexanedione (HD) treatment alters calmodulin, Ca2+/calmodulin-dependent protein kinase II, and protein kinase C in rats' nerve tissues

International Nuclear Information System (INIS)

Wang Qingshan; Hou Liyan; Zhang Cuili; Zhao Xiulan; Yu Sufang; Xie, Ke-Qin

2008-01-01

Calcium-dependent mechanisms, particularly those mediated by Ca 2+ /calmodulin (CaM)-dependent protein kinase II (CaMKII), have been implicated in neurotoxicant-induced neuropathy. However, it is unknown whether similar mechanisms exist in 2,5-hexanedione (HD)-induced neuropathy. For that, we investigated the changes of CaM, CaMKII, protein kinase C (PKC) and polymerization ratios (PRs) of NF-L, NF-M and NF-H in cerebral cortex (CC, including total cortex and some gray), spinal cord (SC) and sciatic nerve (SN) of rats treated with HD at a dosage of 1.75 or 3.50 mmol/kg for 8 weeks (five times per week). The results showed that CaM contents in CC, SC and SN were significantly increased, which indicated elevation of Ca 2+ concentrations in nerve tissues. CaMKII contents and activities were also increased in CC and were positively correlated with gait abnormality, but it could not be found in SC and SN. The increases of PKC contents and activities were also observed in SN and were positively correlated with gait abnormality. Except for that of NF-M in CC, the PRs of NF-L, NF-M and NF-H were also elevated in nerve tissues, which was consistent with the activation of protein kinases. The results suggested that CaMKII might be partly (in CC but not in SC and SN) involved in HD-induced neuropathy. CaMKII and PKC might mediate the HD neurotoxicity by altering the NF phosphorylation status and PRs

The effect of propofol on CA1 pyramidal cell excitability and GABAA-mediated inhibition in the rat hippocampal slice.

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Albertson, T E; Walby, W F; Stark, L G; Joy, R M

1996-05-24

An in vitro paired-pulse orthodromic stimulation technique was used to examine the effects of propofol on excitatory afferent terminals, CA1 pyramidal cells and recurrent collateral evoked inhibition in the rat hippocampal slice. Hippocampal slices 400 microns thick were perfused with oxygenated artificial cerebrospinal fluid, and electrodes were placed in the CA1 region to record extracellular field population spike (PS) or excitatory postsynaptic potential (EPSP) responses to stimulation of Schaffer collateral/commissural fibers. Gamma-aminobutyric acid (GABA)-mediated recurrent inhibition was measured using a paired-pulse technique. The major effect of propofol (7-28 microM) was a dose and time dependent increase in the intensity and duration of GABA-mediated inhibition. This propofol effect could be rapidly and completely reversed by exposure to known GABAA antagonists, including picrotoxin, bicuculline and pentylenetetrazol. It was also reversed by the chloride channel antagonist, 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS). It was not antagonized by central (flumazenil) or peripheral (PK11195) benzodiazepine antagonists. Reversal of endogenous inhibition was also noted with the antagonists picrotoxin and pentylenetetrazol. Input/output curves constructed using stimulus propofol caused only a small enhancement of EPSPs at higher stimulus intensities but had no effect on PS amplitudes. These studies are consistent with propofol having a GABAA-chloride channel mechanism causing its effect on recurrent collateral evoked inhibition in the rat hippocampal slice.

Effects of a single bilateral infusion of R-ketamine in the rat brain regions of a learned helplessness model of depression.

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Shirayama, Yukihiko; Hashimoto, Kenji

2017-03-01

Effects of a single bilateral infusion of R-enantiomer of ketamine in rat brain regions of learned helplessness model of depression were examined. A single bilateral infusion of R-ketamine into infralimbic (IL) portion of medial prefrontal cortex (mPFC), CA3 and dentate gyrus (DG) of the hippocampus showed antidepressant effects. By contrast, a single bilateral infusion of R-ketamine into prelimbic (PL) portion of mPFC, shell and core of nucleus accumbens, basolateral amygdala and central nucleus of the amygdala had no effect. This study suggests that IL of mPFC, CA3 and DG of hippocampus might be involved in the antidepressant actions of R-ketamine.

Involvement of Bax and Bcl2 in Neuroprotective Effect of Curcumin in Kainic Acid-Induced Model of Temporal Lobe Epilepsy in Male Rat

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zahra Kiasalari

2016-04-01

Full Text Available Background & objectives: Temporal lobe epilepsy is associated with neuronal apoptosis. Curcumin has antioxidant and anticonvulsant activities, therefore this study was conducted to assess involvement of Bax and Bcl2 in protective effect of curcumin in epileptic rats. Methods: 28 rats were divided into sham, curcumin-pretreated sham, epileptic (kainate, and curcumin-pretreated epileptic groups. Experimental model of epilepsy was induced by intrahippocampal administration of kainic acid. Rats received curcumin at a dose of 100 mg/kg. Finally, Nissl staining and Bax and Bcl2 immunohistochemistry were conducted on hippocampal sections and data were analyzed using one-way ANOVA and unpaired t-test. The p-value less than 0.05was considered statistically significant. Results: Induction of epilepsy was followed by a significant seizure and curcumin pretreatment significantly reduced seizure intensity (p<0.01. In addition, there were no significant differences between the groups in Nissl staining of CA3 area neurons. In addition, Bax positive neurons were observed in CA3 area in kainate group and significantly decreased in curcumin pretreated rats (p<0.05. Meanwhile, Bcl2 positive neurons were also moderately observed in kainate group and curcumin pretreatment significantly increased it (p<0.05. Conclusion: Curcumin pretreatment exhibits anticonvulsant activity in epileptic rats. It also decreases the expression of pro-apoptotic protein Bax and significantly enhances the expression of anti-apoptotic protein Bcl2 and hence could reduce neuronal apoptosis.

Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) interacts with neurofilament L and inhibits its filament association

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Ozaki, Hana [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Katoh, Tsuyoshi [Department of Biochemistry, Asahikawa Medical University, Asahikawa, 078-8510 (Japan); Nakagawa, Ryoko; Ishihara, Yasuhiro [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Sueyoshi, Noriyuki; Kameshita, Isamu [Department of Life Sciences, Faculty of Agriculture, Kagawa University, Kagawa, 761-0795 (Japan); Taniguchi, Takanobu [Department of Biochemistry, Asahikawa Medical University, Asahikawa, 078-8510 (Japan); Hirano, Tetsuo; Yamazaki, Takeshi [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan); Ishida, Atsuhiko, E-mail: aishida@hiroshima-u.ac.jp [Laboratory of Molecular Brain Science, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, 739-8521 (Japan)

2016-09-02

Ca{sup 2+}/calmodulin-dependent protein kinase phosphatase (CaMKP/PPM1F) is a Ser/Thr phosphatase that belongs to the PPM family. Growing evidence suggests that PPM phosphatases including CaMKP act as a complex with other proteins to regulate cellular functions. In this study, using the two-dimensional far-western blotting technique with digoxigenin-labeled CaMKP as a probe, in conjunction with peptide mass fingerprinting analysis, we identified neurofilament L (NFL) as a CaMKP-binding protein in a Triton-insoluble fraction of rat brain. We confirmed binding of fluorescein-labeled CaMKP (F-CaMKP) to NFL in solution by fluorescence polarization. The analysis showed that the dissociation constant of F-CaMKP for NFL is 73 ± 17 nM (n = 3). Co-immunoprecipitation assay using a cytosolic fraction of NGF-differentiated PC12 cells showed that endogenous CaMKP and NFL form a complex in cells. Furthermore, the effect of CaMKP on self-assembly of NFL was examined. Electron microscopy revealed that CaMKP markedly prevented NFL from forming large filamentous aggregates, suggesting that CaMKP-binding to NFL inhibits its filament association. These findings may provide new insights into a novel mechanism for regulating network formation of neurofilaments during neuronal differentiation. - Highlights: • NFL was identified as a CaMKP-binding protein in an insoluble fraction of rat brain. • CaMKP bound to NFL in solution with a K{sub d} value of 73 ± 17 nM. • A CaMKP-NFL complex was found in NGF-differentiated PC12 cells. • CaMKP-binding to NFL inhibited its filament association. • CaMKP may regulate network formation of neurofilaments in neurons.

Vascular mechanism of action of endothelin-1: Effect of Ca2+ antagonists

International Nuclear Information System (INIS)

Chabrier, P.E.; Auguet, M.; Roubert, P.; Lonchampt, M.O.; Gillard, V.; Guillon, J.M.; Delaflotte, S.; Braquet, P.

1989-01-01

The vasoconstrictive properties of the endothelium-derived peptide, endothelin-1 (ET-1), were investigated on rat isolated aorta and on cultured rat aortic smooth muscle cells. In rat isolated aorta, endothelin-1 induced a slow and sustained contraction in a Ca2+-free medium; after calcium readmission, an additional sustained contraction was elicited. In vascular smooth muscle cells, endothelin-1 provoked a dose-dependent Ca2+ influx that was not inhibited by calcium entry blockers (nifedipine, D 600, or diltiazem). In these cells, [ 125 I]-endothelin-1 bound to a specific, saturable, and high affinity recognition site (Kd about 10(-9) M and Bmax = 52 +/- 2 fmol/10(6) cells). The binding was not reversible and not affected by calcium antagonists. These data do not support the hypothesis that endothelin-1 acts as an endogenous agonist of the voltage-dependent Ca2+ channels. The action of endothelin-1 can be separated into two components: one dependent on Ca2+ influx but insensitive to calcium antagonists and another independent of extracellular Ca2+. The irreversible binding of endothelin-1 may reflect an internalization of the ligand inside the cell membrane, leading to multiple contractile events

Efficacy of the chelating agent CaEDTA in reversing lead-induced changes in behavior.

Science.gov (United States)

Cory-Slechta, D A; Weiss, B

1989-01-01

The chelating agent CaEDTA has been reported to reverse the deficits in intellectual function and performance associated with Pb (lead) exposure in children. However, such studies have not included rigorous controls for the intervention procedures per se. The experiments reported here examined reversibility of performance changes in a rat model based on behavior sensitive to low-level Pb exposure. Rats were exposed to 50 ppm sodium or Pb acetate in drinking water from weaning. Performance maintained under a Fixed-Interval schedule of food reinforcement began at 55 days of age. Following the onset of the characteristic increase in short interresponse times (IRTs) associated with low-level Pb exposure after 35 experimental sessions, Pb treatment was terminated. Animals within both the control and Pb groups were then matched on the basis of performance indices and injected daily for 5 days with either saline, 75 mg/kg or 150 mg/kg CaEDTA. Subsequent changes in F1 performance were monitored for 35-60 sessions. No consistent effects of CaEDTA were detected in control animals. CaEDTA treatment failed to reverse the behavioral effects in Pb-exposed animals. If anything, it tended to further increase the proportion of short IRTs. These data suggest that better controlled clinical studies are warranted to evaluate the efficacy of CaEDTA in reversing Pb-induced behavioral effects before its application for these purposes becomes widespread.

Comparison of the influence of two models of mild stress on hippocampal brain-derived neurotrophin factor (BDNF) immunoreactivity in old age rats.

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Badowska-Szalewska, Ewa; Ludkiewicz, Beata; Krawczyk, Rafał; Melka, Natalia; Moryś, Janusz

2017-01-01

The way hippocampal neurons function during stress in old age (critical times of life) is dependent on brain derived neurotrophin factor (BDNF). This study examined the influence of acute and chronic forced swim (FS) or high-light open field (HL‑OF) stimulation on the density of BDNF immunoreactive (ir) neurons in the hippocampal pyramidal layers of CA1, CA2, CA3 regions and the granular layer of dentate gyrus (DG) in old (postnatal day 720; P720) Wistar Han rats. Our data showed that in comparison with non-stressed rats, acute FS caused a significant increase in the density of BDNF-ir neurons in CA2 and CA3, while acute HL-OF led to an increase in this factor in all hippocampal subfields with the exception of DG. However, the density of BDNF-ir cells remained unchanged after exposure to chronic FS or HL‑OF in the hippocampal regions in relation to the control rats. These results indicate that acute FS or HL-OF proved to be a stressor that induces an increase in the density of BDNF-ir pyramidal neurons, which was probably connected with up-regulation of HPA axis activity and short‑time memory processing of the stressful situation. Moreover, as far as the influence on BDNF-ir cells in hippocampus is concerned, chronic FS or HL-OF was not an aggravating factor for rats in the ontogenetic periods studied.

Cadmium induces Ca2+ mediated, calpain-1/caspase-3-dependent apoptosis in primary cultured rat proximal tubular cells.

Science.gov (United States)

Wang, Hong; Zhai, Nianhui; Chen, Ying; Xu, Haibin; Huang, Kehe

2017-07-01

Calcium, as a ubiquitous second messenger, governs a large array of cellular processes and is necessary for cell survival. More recently, it was observed that the cytosolic Ca 2+ concentration ([Ca 2+ ] c ) elevation could induce apoptosis in primary cultured rat proximal tubular (rPT) cells exposed to cadmium (Cd), but the concrete mechanism is still unclear. This study was designed to investigate the signal pathway involved in [Ca 2+ ] c elevation-mediated apoptosis. The results confirmed the elevation of [Ca 2+ ] c by confocal microscopy and enhancement of the apoptosis by Hoechst 33258 staining and flow cytometer when rPT cells were exposed to Cd for 12h. Then we demonstrated that Cd enhanced the protein levels of active calpain-1 and caspase-3 in rPT cells. Pretreatment with a cytosolic Ca 2+ chelator, 1,2-Bis (2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM), markedly blocked the up-regulation of active calpain-1 and caspase-3 and inhibited the apoptosis induced by Cd. Further, rPT cells were pretreated with a cell-permeable selective calpain-1 inhibitor, 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) and caspase-3 inhibitor, N-Acetyl-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO), respectively. PD150606 significantly attenuated the up-regulation of active caspase-3 and the apoptosis induced by Cd. As expected, inhibition of active caspase-3 by Ac-DEVD-CHO decreased the apoptosis induced by Cd. Taken together, it could be concluded that [Ca 2+ ] c elevation did act as a pro-apoptotic signal in Cd-induced cytotoxicity of rPT cells, triggered calpain-1 and caspase-3 activation in turn, and induced apoptosis of rPT cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Hydrogen peroxide modulates Ca2+-activation of single permeabilized fibres from fast- and slow-twitch skeletal muscles of rats.

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Plant, D R; Lynch, G S; Williams, D A

2000-01-01

We examined the effects of redox modulation on single membrane-permeabilized fibre segments from the fast-twitch extensor digitorum longus (EDL) and slow-twitch soleus muscles of adult rats to determine whether the contractile apparatus was the redox target responsible for the increased contractility of muscles exposed to low concentrations of H2O2. The effects of H2O2 on maximum Ca2+-activated force were dose-dependent with 30 min exposure to 5 mM H2O2 causing a progressive decrease by 22+/-3 and 13+/-2% in soleus and EDL permeabilized muscle fibres, respectively. Lower concentrations of exogenous H2O2 (100 microM and 1 mM) had no effect on maximum Ca2+-activated force. Subsequent exposure to the reductant dithiothreitol (DTT, 10 mM, 10 min) fully reversed the H2O2-induced depression of force in EDL, but not in soleus muscle fibres. Incubation with DTT alone for 10 min did not alter Ca2+-activated force in either soleus or EDL muscle fibres. The sensitivity of the contractile filaments to Ca2+ (pCa50) was not altered by exposure to any concentration of exogenous H2O2. However, all concentrations of H2O2 diminished the Hill coefficient in permeabilized fibres from the EDL muscle, indicating that the cooperativity of Ca2+ binding to troponin is altered. H2O2 (5 mM) did not affect rigor force, which indicates that the number of crossbridges participating in contraction was not reduced. In conclusion, H2O2 may reduce the maximum Ca2+ activated force production in skinned muscle fibres by decreasing the force per crossbridge.

Controls over δ44/40Ca and Sr/Ca variations in coccoliths: New perspectives from laboratory cultures and cellular models

Science.gov (United States)

Mejía, Luz María; Paytan, Adina; Eisenhauer, Anton; Böhm, Florian; Kolevica, Ana; Bolton, Clara; Méndez-Vicente, Ana; Abrevaya, Lorena; Isensee, Kirsten; Stoll, Heather

2018-01-01

Coccoliths comprise a major fraction of the global carbonate sink. Therefore, changes in coccolithophores' Ca isotopic fractionation could affect seawater Ca isotopic composition, affecting interpretations of the global Ca cycle and related changes in seawater chemistry and climate. Despite this, a quantitative interpretation of coccolith Ca isotopic fractionation and a clear understanding of the mechanisms driving it are not yet available. Here, we address this gap in knowledge by developing a simple model (CaSri-Co) to track coccolith Ca isotopic fractionation during cellular Ca uptake and allocation to calcification. We then apply it to published and new δ 44 / 40 Ca and Sr/Ca data of cultured coccolithophores of the species Emiliania huxleyi and Gephyrocapsa oceanica. We identify changes in calcification rates, Ca retention efficiency and solvation-desolvation rates as major drivers of the Ca isotopic fractionation and Sr/Ca variations observed in cultures. Higher calcification rates, higher Ca retention efficiencies and lower solvation-desolvation rates increase both coccolith Ca isotopic fractionation and Sr/Ca. Coccolith Ca isotopic fractionation is most sensitive to changes in solvation-desolvation rates. Changes in Ca retention efficiency may be a major driver of coccolith Sr/Ca variations in cultures. We suggest that substantial changes in the water structure strength caused by past changes in temperature could have induced significant changes in coccolithophores' Ca isotopic fractionation, potentially having some influence on seawater Ca isotopic composition. We also suggest a potential effect on Ca isotopic fractionation via modification of the solvation environment through cellular exudates, a hypothesis that remains to be tested.

Antidepressant-like effects and possible mechanisms of amantadine on cognitive and synaptic deficits in a rat model of chronic stress.

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Yu, Mei; Zhang, Yuan; Chen, Xiaoyu; Zhang, Tao

2016-01-01

The aim of this study was to examine whether amantadine (AMA), as a low-affinity noncompetitive N-methyl-d-aspartate (NMDA) receptor antagonist, is able to improve cognitive deficits caused by chronic stress in rats. Male Wistar rats were divided into four groups: control, control + AMA, stress and stress + AMA groups. The chronic stress model combined chronic unpredictable stress (CUS) with isolated feeding. Animals were exposed to CUS continued for 21 days. AMA (25 mg/kg) was administrated p.o. for 20 days from the 4th day of CUS to the 23rd. Weight and sucrose consumption were measured during model establishing period. Spatial memory was evaluated using the Morris water maze (MWM) test. Following MWM testing, both long-term potentiation (LTP) and depotentiation were recorded in the hippocampal CA1 region. NR2B and postsynaptic density protein 95 (PSD-95) proteins were measured by Western-blot analysis. AMA increased weight and sucrose consumption of stressed rats. Spatial memory and reversal learning in stressed rats were impaired relative to controls, whereas AMA significantly attenuated cognitive impairment. AMA also mitigated the chronic stress-induced impairment of hippocampal synaptic plasticity, in which both the LTP and depotentiation were significantly inhibited in stressed rats. Moreover, AMA enhanced the expression of hippocampal NR2B and PSD-95 in stressed rats. The data suggest that AMA may be an effective therapeutic agent for depression-like symptoms and associated cognitive disturbances.

Preparation of liposomal amiodarone and investigation of its cardiomyocyte-targeting ability in cardiac radiofrequency ablation rat model

Directory of Open Access Journals (Sweden)

Zhuge Y

2016-05-01

Full Text Available Ying Zhuge,1,* Zhi-Feng Zheng,1,* Mu-Qing Xie,2 Lin Li,2 Fang Wang,1 Feng Gao2,3 1Department of Cardiology, Shanghai First People’s Hospital of Nanjing Medical University, 2Department of Pharmaceutics, School of Pharmacy, 3Shanghai Key Laboratory of Functional Materials Chemistry, East China University of Science and Technology, Shanghai, People’s Republic of China*These authors contributed equally to this workAbstract: The objective of this study was to develop an amiodarone hydrochloride (ADHC-loaded liposome (ADHC-L formulation and investigate its potential for cardiomyocyte targeting after cardiac radiofrequency ablation (CA in vivo. The ADHC-L was prepared by thin-film method combined with ultrasonication and extrusion. The preparation process was optimized by Box–Behnken design with encapsulation efficiency as the main evaluation index. The optimum formulation was quantitatively obtained with a diameter of 99.9±0.4 nm, a zeta potential of 35.1±10.9 mV, and an encapsulation efficiency of 99.5%±13.3%. Transmission electron microscopy showed that the liposomes were spherical particles with integrated bilayers and well dispersed with high colloidal stability. Pharmacokinetic studies were investigated in rats after intravenous administration, which revealed that compared with free ADHC treatment, ADHC-L treatment showed a 5.1-fold increase in the area under the plasma drug concentration–time curve over a period of 24 hours (AUC0–24 h and an 8.5-fold increase in mean residence time, suggesting that ADHC-L could facilitate drug release in a more stable and sustained manner while increasing the circulation time of ADHC, especially in the blood. Biodistribution studies of ADHC-L demonstrated that ADHC concentration in the heart was 4.1 times higher after ADHC-L treatment in CA rat model compared with ADHC-L sham-operated treatment at 20 minutes postinjection. Fluorescence imaging studies further proved that the heart

Regulation of Blood Pressure by Targeting CaV1.2-Galectin-1 Protein Interaction.

Science.gov (United States)

Hu, Zhenyu; Li, Guang; Wang, Jiong-Wei; Chong, Suet Yen; Yu, Dejie; Wang, Xiaoyuan; Soon, Jia Lin; Liang, Mui Cheng; Wong, Yuk Peng; Huang, Na; Colecraft, Henry M; Liao, Ping; Soong, Tuck Wah

2018-04-12

Background -L-type Ca V 1.2 channels play crucial roles in regulation of blood pressure. Galectin-1 (Gal-1), has been reported to bind to the I-II loop of Ca V 1.2 channels to reduce their current density. However, the mechanistic understanding for the down-regulation of Ca V 1.2 channels by Gal-1, and whether Gal-1 plays a direct role in blood pressure regulation remain unclear. Methods - In vitro experiments involving co-IP, western blot, patch-clamp recordings, immunohistochemistry and pressure myography were used to evaluate the molecular mechanisms by which Gal-1 down-regulates Ca V 1.2 channel in transfected HEK 293 cells, smooth muscle cells, arteries from Lgasl1 -/- mice, rat and human patients. In vivo experiments involving delivery of Tat-e9c peptide and AAV5-Gal-1 into rats were performed to investigate the effect of targeting Ca V 1.2-Gal-1 interaction on blood pressure monitored by tail cuff or telemetry methods. Results -Our study reveals that Gal-1 is a key regulator for proteasomal degradation of Ca V 1.2 channels. Gal-1 competed allosterically with Ca V β subunit for binding to the I-II loop of Ca V 1.2 channel. This competitive disruption of Ca V β binding led to Ca V 1.2 degradation by exposing the channels to poly-ubiquitination. Notably, we demonstrated that the inverse relationship of reduced Gal-1 and increased Ca V 1.2 protein levels in arteries was associated with hypertension in hypertensive rats and patients, and Gal-1 deficiency induces higher blood pressure in mice due to up-regulated Ca V 1.2 protein level in arteries. To directly regulate blood pressure by targeting the Ca V 1.2-Gal-1 interaction, we administered Tat-e9c, a peptide that competed for binding of Gal-1, by a mini-osmotic pump and this specific disruption of Ca V 1.2-Gal-1 coupling increased smooth muscle Ca V 1.2 currents, induced larger arterial contraction and caused hypertension in rats. In contrasting experiments, over-expression of Gal-1 in smooth muscle by a

Role of calpain in eccentric contraction-induced proteolysis of Ca2+-regulatory proteins and force depression in rat fast-twitch skeletal muscle.

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Kanzaki, Keita; Watanabe, Daiki; Kuratani, Mai; Yamada, Takashi; Matsunaga, Satoshi; Wada, Masanobu

2017-02-01

The aim of this study was to examine the in vivo effects of eccentric contraction (ECC) on calpain-dependent proteolysis of Ca 2+ -regulatory proteins and force production in fast-twitch skeletal muscles. Rat extensor digitorum longus muscles were exposed to 200 repeated ECC in situ and excised immediately [recovery 0 (REC0)] or 3 days [recovery 3 (REC3)] after cessation of ECC. Calpain inhibitor (CI)-treated rats were intraperitoneally injected with MDL-28170 before ECC and during REC3. Tetanic force was markedly reduced at REC0 and remained reduced at REC3. CI treatment ameliorated the ECC-induced force decline but only at REC3. No evidence was found for proteolysis of dihydropyridine receptor (DHPR), junctophilin (JP)1, JP2, ryanodine receptor (RyR), sarcoplasmic reticulum Ca 2+ -ATPase (SERCA)1a, or junctional face protein-45 at REC0. At REC3, ECC resulted in decreases in DHPR, JP1, JP2, RyR, and SERCA1a. CI treatment prevented the decreases in DHPR, JP1, and JP2, whereas it had little effect on RyR and SERCA1a. These findings suggest that DHPR, JP1, and JP2, but not RyR and SERCA1a, undergo calpain-dependent proteolysis in in vivo muscles subjected to ECC and that impaired function of DHPR and/or JP might cause prolonged force deficits with ECC. NEW & NOTEWORTHY Calpain-dependent proteolysis is one of the contributing factors to muscle damage that occurs with eccentric contraction (ECC). It is unclear, however, whether calpains account for proteolysis of Ca 2+ -regulatory proteins in in vivo muscles subjected to ECC. Here, we provide evidence that dihydropyridine receptor and junctophilin, but not ryanodine receptor and sarcoplasmic reticulum Ca 2+ -ATPase, undergo calpain-dependent proteolysis. Copyright © 2017 the American Physiological Society.

Activation of calcium-sensing receptor increases TRPC3 expression in rat cardiomyocytes

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Feng, Shan-Li [Department of Clinical Laboratory, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086 (China); Sun, Ming-Rui [Department of Pharmacology, Qiqihaer Medical College, Qiqihaer 160001 (China); Li, Ting-Ting; Yin, Xin [Department of Clinical Laboratory, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086 (China); Xu, Chang-Qing [Department of Pathophysiology, Harbin Medical University, Harbin 150086 (China); Sun, Yi-Hua, E-mail: syh200415@126.com [Department of Clinical Laboratory, The Second Affiliated Hospital of Harbin Medical University, Harbin 150086 (China)

2011-03-11

Research highlights: {yields} Calcium-sensing receptor (CaR) activation stimulates TRP channels. {yields} CaR promoted transient receptor potential C3 (TRPC3) expression. {yields} Adult rat ventricular myocytes display capacitative calcium entry (CCE), which was operated by TRPCs. {yields} TRPC channels activation induced by CaR activator sustained the increased [Ca{sup 2+}]{sub i} to evoke cardiomyocytes apoptosis. -- Abstract: Transient receptor potential (TRP) channels are expressed in cardiomyocytes, which gate a type of influx of extracellular calcium, the capacitative calcium entry. TRP channels play a role in mediating Ca{sup 2+} overload in the heart. Calcium-sensing receptors (CaR) are also expressed in rat cardiac tissue and promote the apoptosis of cardiomyocytes by Ca{sup 2+} overload. However, data about the link between CaR and TRP channels in rat heart are few. In this study, reverse transcriptase polymerase chain reaction (RT-PCR) and Western blotting were used to examine the expression of the TRP canonical proteins TRPC1 and TRPC3 in adult and neonatal rat cardiomyocytes. Laser scan confocal microscopy was used to detect intracellular [Ca{sup 2+}]{sub i} levels in isolated adult rat ventricular myocytes. The results showed that, in adult rat cardiomyocytes, the depletion of Ca{sup 2+} stores in the endoplasmic/sarcoplasmic reticulum (ER/SR) by thapsigargin induced a transient increase in [Ca{sup 2+}]{sub i} in the absence of [Ca{sup 2+}]{sub o} and the subsequent restoration of [Ca{sup 2+}]{sub o} sustained the increased [Ca{sup 2+}]{sub i} for a few minutes, whereas, the persisting elevation of [Ca{sup 2+}]{sub i} was reduced in the presence of the TRPC inhibitor SKF96365. The stimulation of CaR by its activator gadolinium chloride (GdCl{sub 3}) or spermine also resulted in the same effect and the duration of [Ca{sup 2+}]{sub i} increase was also shortened in the absence of [Ca{sup 2+}]{sub o}. In adult and neonatal rat cardiomyocytes, GdCl{sub 3

Distal C terminus of CaV1.2 channels plays a crucial role in the neural differentiation of dental pulp stem cells.

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Jianping Ge

Full Text Available L-type voltage-dependent CaV1.2 channels play an important role in the maintenance of intracellular calcium homeostasis, and influence multiple cellular processes. C-terminal cleavage of CaV1.2 channels was reported in several types of excitable cells, but its expression and possible roles in non-excitable cells is still not clear. The aim of this study was to determine whether distal C-terminal fragment of CaV1.2 channels is present in rat dental pulp stem cells and its possible role in the neural differentiation of rat dental pulp stem cells. We generated stable CaV1.2 knockdown cells via short hairpin RNA (shRNA. Rat dental pulp stem cells with deleted distal C-terminal of CaV1.2 channels lost the potential of differentiation to neural cells. Re-expression of distal C-terminal of CaV1.2 rescued the effect of knocking down the endogenous CaV1.2 on the neural differentiation of rat dental pulp stem cells, indicating that the distal C-terminal of CaV1.2 is required for neural differentiation of rat dental pulp stem cells. These results provide new insights into the role of voltage-gated Ca(2+ channels in stem cells during differentiation.

Minocycline attenuates cognitive impairment induced by isoflurane anesthesia in aged rats.

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Feijuan Kong

Full Text Available Postoperative cognitive dysfunction (POCD is a clinical phenomenon characterized by cognitive deficits in patients after anesthesia and surgery, especially in geriatric surgical patients. Although it has been documented that isoflurane exposure impaired cognitive function in several aged animal models, there are few clinical interventions and treatments available to prevent this disorder. Minocycline has been well established to exert neuroprotective effects in various experimental animal models and neurodegenerative diseases. Therefore, we hypothesized that pretreatment with minocycline attenuates isoflurane-induced cognitive decline in aged rats. In the present study, twenty-month-old rats were administered minocycline or an equal volume of saline by intraperitoneal injection 12 h before exposure to isoflurane. Then the rats were exposed to 1.3% isoflurane for 4 h. Two weeks later, spatial learning and memory of the rats were examined using the Morris Water Maze. We found that pretreatment with minocycline mitigated isoflurane-induced cognitive deficits and suppressed the isoflurane-induced excessive release of IL-1β and caspase-3 in the hippocampal CA1 region at 4 h after isoflurane exposure, as well as the number of TUNEL-positive nuclei. In addition, minocycline treatment also prevented the changes of synaptic ultrastructure in the hippocampal CA1 region induced by isoflurane. In conclusion, pretreatment with minocycline attenuated isoflurane-induced cognitive impairment in aged rats.

Steroid-associated osteonecrosis animal model in rats

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Li-Zhen Zheng

2018-04-01

Full Text Available Summary: Objective: Established preclinical disease models are essential for not only studying aetiology and/or pathophysiology of the relevant diseases but more importantly also for testing prevention and/or treatment concept(s. The present study proposed and established a detailed induction and assessment protocol for a unique and cost-effective preclinical steroid-associated osteonecrosis (SAON in rats with pulsed injections of lipopolysaccharide (LPS and methylprednisolone (MPS. Methods: Sixteen 24-week-old male Sprague–Dawley rats were used to induce SAON by one intravenous injection of LPS (0.2 mg/kg and three intraperitoneal injections of MPS (100 mg/kg with a time interval of 24 hour, and then, MPS (40 mg/kg was intraperitoneally injected three times a week from week 2 until sacrifice. Additional 12 rats were used as normal controls. Two and six weeks after induction, animals were scanned by metabolic dual energy X-ray absorptiometry for evaluation of tissue composition; serum was collected for bone turnover markers, Microfil perfusion was performed for angiography, the liver was collected for histopathology and bilateral femora and bilateral tibiae were collected for histological examination. Results: Three rats died after LPS injection, i.e., with 15.8% (3/19 mortality. Histological evaluation showed 100% incidence of SAON at week 2. Dual energy X-ray absorptiometry showed significantly higher fat percent and lower lean mass in SAON group at week 6. Micro-computed tomography (Micro-CT showed significant bone degradation at proximal tibia 6 weeks after SAON induction. Angiography illustrated significantly less blood vessels in the proximal tibia and significantly more leakage particles in the distal tibia 2 weeks after SAON induction. Serum amino-terminal propeptide of type I collagen and osteocalcin were significantly lower at both 2 and 6 weeks after SAON induction, and serum carboxy-terminal telopeptide was significantly

Studies on the Protective Effects of Scutellarein against Neuronal Injury by Ischemia through the Analysis of Endogenous Amino Acids and Ca2+ Concentration Together with Ca2+-ATPase Activity

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Hao Tang

2015-01-01

Full Text Available Scutellarin, which is extracted from the dried plant of Erigeron breviscapus, has been reported to protect the neural injury against excitotoxicity induced by ischemia. However, there are a few studies on the protective effects of scutellarein, which is the main metabolite of scutellarin in vivo. Thus, this study investigated the neuroprotective effects of scutellarein on cerebral ischemia/reperfusion in rats by bilateral common carotid artery occlusion (BCCAO model, through the analysis of endogenous amino acids using HILIC-MS/MS, and evaluation of Ca2+ concentration together with Ca2+-ATPase activity. The results showed that scutellarein having good protective effects on cerebral ischemia/reperfusion might by decreasing the excitatory amino acids, increasing the inhibitory amino acids, lowing intracellular Ca2+ level, and improving Ca2+-ATPase activity, which suggested that scutellarein might be a promising potent agent for the therapy of ischemic cerebrovascular disease.

Ensemble place codes in hippocampus: CA1, CA3, and dentate gyrus place cells have multiple place fields in large environments.

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Eunhye Park

Full Text Available Previously we reported that the hippocampus place code must be an ensemble code because place cells in the CA1 region of hippocampus have multiple place fields in a more natural, larger-than-standard enclosure with stairs that permitted movements in 3-D. Here, we further investigated the nature of hippocampal place codes by characterizing the spatial firing properties of place cells in the CA1, CA3, and dentate gyrus (DG hippocampal subdivisions as rats foraged in a standard 76-cm cylinder as well as a larger-than-standard box (1.8 m×1.4 m that did not have stairs or any internal structure to permit movements in 3-D. The rats were trained to forage continuously for 1 hour using computer-controlled food delivery. We confirmed that most place cells have single place fields in the standard cylinder and that the positional firing pattern remapped between the cylinder and the large enclosure. Importantly, place cells in the CA1, CA3 and DG areas all characteristically had multiple place fields that were irregularly spaced, as we had reported previously for CA1. We conclude that multiple place fields are a fundamental characteristic of hippocampal place cells that simplifies to a single field in sufficiently small spaces. An ensemble place code is compatible with these observations, which contradict any dedicated coding scheme.

Corticosterone rapidly increases thorns of CA3 neurons via synaptic/extranuclear glucocorticoid receptor in rat hippocampus

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Miyuki eYoshiya

2013-11-01

Full Text Available Modulation of synapses under acute stress is attracting much attention. Exposure to acute stress induces corticosterone (CORT secretion from the adrenal cortex, resulting in rapid increase of CORT levels in plasma and the hippocampus. We tried to test whether rapid CORT effects involve activation of essential kinases as non-genomic processes.We demonstrated rapid effects (~ 1 h of CORT on the density of thorns, by imaging Lucifer Yellow-injected neurons in adult male rat hippocampal slices. Thorns of thorny excrescences of CA3 hippocampal neurons are post-synaptic regions whose presynaptic partners are mossy fiber terminals. The application of CORT at 100, 500 and 1000 nM induced a rapid increase in the density of thorns in the stratum lucidum of CA3 pyramidal neurons. Co-administration of RU486, an antagonist of glucocorticoid receptor (GR, abolished the effect of CORT. Blocking a single kinase, including MAPK, PKA or PKC, suppressed CORT-induced enhancement of thorn-genesis. On the other hand, GSK-3β was not involved in the signaling of thorn-genesis. Blocking AMPA receptors suppressed the CORT effect. Expression of CA3 synaptic/extranuclear GR was demonstrated by immunogold electron microscopic analysis. From these results, stress levels of CORT (100-1000 nM might drive the rapid thorn-genesis via synaptic/extranuclear GR and multiple kinase pathways, although a role of nuclear GRs cannot be completely excluded.

Behaviorally activated mRNA expression profiles produce signatures of learning and enhanced inhibition in aged rats with preserved memory.

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Haberman, Rebecca P; Colantuoni, Carlo; Koh, Ming Teng; Gallagher, Michela

2013-01-01

Aging is often associated with cognitive decline, but many elderly individuals maintain a high level of function throughout life. Here we studied outbred rats, which also exhibit individual differences across a spectrum of outcomes that includes both preserved and impaired spatial memory. Previous work in this model identified the CA3 subfield of the hippocampus as a region critically affected by age and integral to differing cognitive outcomes. Earlier microarray profiling revealed distinct gene expression profiles in the CA3 region, under basal conditions, for aged rats with intact memory and those with impairment. Because prominent age-related deficits within the CA3 occur during neural encoding of new information, here we used microarray analysis to gain a broad perspective of the aged CA3 transcriptome under activated conditions. Behaviorally-induced CA3 expression profiles differentiated aged rats with intact memory from those with impaired memory. In the activated profile, we observed substantial numbers of genes (greater than 1000) exhibiting increased expression in aged unimpaired rats relative to aged impaired, including many involved in synaptic plasticity and memory mechanisms. This unimpaired aged profile also overlapped significantly with a learning induced gene profile previously acquired in young adults. Alongside the increased transcripts common to both young learning and aged rats with preserved memory, many transcripts behaviorally-activated in the current study had previously been identified as repressed in the aged unimpaired phenotype in basal expression. A further distinct feature of the activated profile of aged rats with intact memory is the increased expression of an ensemble of genes involved in inhibitory synapse function, which could control the phenotype of neural hyperexcitability found in the CA3 region of aged impaired rats. These data support the conclusion that aged subjects with preserved memory recruit adaptive mechanisms to

Quantitative assessment of CA1 local circuits: knowledge base for interneuron-pyramidal cell connectivity.

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Bezaire, Marianne J; Soltesz, Ivan

2013-09-01

In this work, through a detailed literature review, data-mining, and extensive calculations, we provide a current, quantitative estimate of the cellular and synaptic constituents of the CA1 region of the rat hippocampus. Beyond estimating the cell numbers of GABAergic interneuron types, we calculate their convergence onto CA1 pyramidal cells and compare it with the known input synapses on CA1 pyramidal cells. The convergence calculation and comparison are also made for excitatory inputs to CA1 pyramidal cells. In addition, we provide a summary of the excitatory and inhibitory convergence onto interneurons. The quantitative knowledge base assembled and synthesized here forms the basis for data-driven, large-scale computational modeling efforts. Additionally, this work highlights specific instances where the available data are incomplete, which should inspire targeted experimental projects toward a more complete quantification of the CA1 neurons and their connectivity. Copyright © 2013 Wiley Periodicals, Inc.

Calcium isotope signature: new proxy for net change in bone volume for chronic kidney disease and diabetic rats.

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Tanaka, Yu-Ki; Yajima, Nobuyuki; Higuchi, Yusuke; Yamato, Hideyuki; Hirata, Takafumi

2017-12-01

Herein, we measure the Ca isotope ratios ( 44 Ca/ 42 Ca and 43 Ca/ 42 Ca) in serum and bone samples collected from rats with chronic kidney disease (CKD) or diabetes mellitus (DM). For the serum samples, the isotope ratios are lower for the CKD (δ 44 Ca/ 42 Ca serum = 0.16 ± 0.11‰; 2SD, n = 6) and the DM (δ 44 Ca/ 42 Ca serum = -0.11 ± 0.25‰; 2SD, n = 7) rats than that for the control rats (δ 44 Ca/ 42 Ca serum = 0.25 ± 0.04‰; 2SD, n = 7). Bone samples from two distinct positions of 20 rats in total, namely, the center and proximal parts of the tibial diaphysis, are subject to Ca isotope analysis. The resulting δ 44 Ca/ 42 Ca values for the bone of the proximal part are about 0.3‰ lower than that for the serum samples from the same rats. The larger isotope fractionations between the serum and bone are consistent with previously reported data for vertebrate animals (e.g., Skulan and DePaolo, 1999), which suggests the preferential incorporation of lighter Ca isotopes through bone formation. For the bones from the control and CKD rats, there were no differences in the δ 44 Ca/ 42 Ca values between the positions of the bone. In contrast, the δ 44 Ca/ 42 Ca values of the bone for the DM rats were different between the positions of the bone. Due to the lower bone turnover rate for the DM rats, the δ 44 Ca/ 42 Ca for the middle of the diaphysis can reflect the Ca isotopes in the bone formed prior to the progression of DM states. Thus, the resulting δ 44 Ca/ 42 Ca values show a clear correlation with bone mineral density (BMD). This can be due to the release of isotopically lighter Ca from the bone to the serum. In the present study, our data demonstrate that the δ 44 Ca/ 42 Ca value for serum can be used as a new biomarker for evaluating changes in bone turnover rate, followed by changes in bone volume.

How informative are spatial CA3 representations established by the dentate gyrus?

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Erika Cerasti

2010-04-01

Full Text Available In the mammalian hippocampus, the dentate gyrus (DG is characterized by sparse and powerful unidirectional projections to CA3 pyramidal cells, the so-called mossy fibers. Mossy fiber synapses appear to duplicate, in terms of the information they convey, what CA3 cells already receive from entorhinal cortex layer II cells, which project both to the dentate gyrus and to CA3. Computational models of episodic memory have hypothesized that the function of the mossy fibers is to enforce a new, well-separated pattern of activity onto CA3 cells, to represent a new memory, prevailing over the interference produced by the traces of older memories already stored on CA3 recurrent collateral connections. Can this hypothesis apply also to spatial representations, as described by recent neurophysiological recordings in rats? To address this issue quantitatively, we estimate the amount of information DG can impart on a new CA3 pattern of spatial activity, using both mathematical analysis and computer simulations of a simplified model. We confirm that, also in the spatial case, the observed sparse connectivity and level of activity are most appropriate for driving memory storage-and not to initiate retrieval. Surprisingly, the model also indicates that even when DG codes just for space, much of the information it passes on to CA3 acquires a non-spatial and episodic character, akin to that of a random number generator. It is suggested that further hippocampal processing is required to make full spatial use of DG inputs.

Nitric oxide-dependent vasodilation and Ca2+ signalling induced by erythrodiol in rat aorta

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Fidèle Ntchapda

2015-06-01

Full Text Available Objective: To evaluate the pharmacological property of erythrodiol, a natural triterpenoid contained in propolis, as vasodilatory agent, and to determine its mechanism of action. Methods: Rats aortic rings were isolated and suspended in organ baths, and the effects of erythrodiol were studied by means of isometric tension recording experiments. Nitric oxide (NO was detected by ozone-induced chemiluminescence. The technique used to evaluate changes in intracellular Ca2+ concentration in intact endothelium was opened aortic ring and loaded with 16 µmol Fura-2/AM for 60 min at room temperature, washed and fixed by small pins with the luminal face up. In situ, ECs were visualized by an upright epifluorescence Axiolab microscope (Carl Zeiss, Oberkochen, Germany equipped with a Zeiss×63 Achroplan objective (water immersion, 2.0 mm working distance, 0.9 numerical apertures. ECs were excited alternately at 340 and 380 nm, and the emitted light was detected at 510 nm. Results: In aortic rings with intact endothelium pre-contracted with norepinephrine (10-4 mol/L, the addition of erythrodiol (10-8-10-4 mol/L induced vasorelaxation in a concentration-dependent manner; in endothelium-denuded rings, the relaxant response induced by erythrodiol was almost completely abolished suggesting that vasorelaxation was endothelium-dependent. They had almost no relaxant effect on depolarised or endothelium-denuded aortic segments. The relaxation was significantly attenuated by pre-treatment with the NO synthase inhibitor Nvnitro-L-arginine-methylester. Erythrodiol (10-4 mol/L was able to significantly increase NOx levels. This effect was completely abolished after removal of the vascular endothelium. Erythrodiol (100 µmol/L caused a slow, long-lasting increase in intracellular Ca2+ concentration. These results further supported the hypothesis that erythrodiol can induce activation of the NO/soluble guanylate cyclase/cyclic guanosine monophosphate pathway, as

Glucose-Dependent Insulin Secretion in Pancreatic β-Cell Islets from Male Rats Requires Ca2+ Release via ROS-Stimulated Ryanodine Receptors.

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Paola Llanos

Full Text Available Glucose-stimulated insulin secretion (GSIS from pancreatic β-cells requires an increase in intracellular free Ca2+ concentration ([Ca2+]. Glucose uptake into β-cells promotes Ca2+ influx and reactive oxygen species (ROS generation. In other cell types, Ca2+ and ROS jointly induce Ca2+ release mediated by ryanodine receptor (RyR channels. Therefore, we explored here if RyR-mediated Ca2+ release contributes to GSIS in β-cell islets isolated from male rats. Stimulatory glucose increased islet insulin secretion, and promoted ROS generation in islets and dissociated β-cells. Conventional PCR assays and immunostaining confirmed that β-cells express RyR2, the cardiac RyR isoform. Extended incubation of β-cell islets with inhibitory ryanodine suppressed GSIS; so did the antioxidant N-acetyl cysteine (NAC, which also decreased insulin secretion induced by glucose plus caffeine. Inhibitory ryanodine or NAC did not affect insulin secretion induced by glucose plus carbachol, which engages inositol 1,4,5-trisphosphate receptors. Incubation of islets with H2O2 in basal glucose increased insulin secretion 2-fold. Inhibitory ryanodine significantly decreased H2O2-stimulated insulin secretion and prevented the 4.5-fold increase of cytoplasmic [Ca2+] produced by incubation of dissociated β-cells with H2O2. Addition of stimulatory glucose or H2O2 (in basal glucose to β-cells disaggregated from islets increased RyR2 S-glutathionylation to similar levels, measured by a proximity ligation assay; in contrast, NAC significantly reduced the RyR2 S-glutathionylation increase produced by stimulatory glucose. We propose that RyR2-mediated Ca2+ release, induced by the concomitant increases in [Ca2+] and ROS produced by stimulatory glucose, is an essential step in GSIS.

Muscle-Type Specific Autophosphorylation of CaMKII Isoforms after Paced Contractions

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Wouter Eilers

2014-01-01

Full Text Available We explored to what extent isoforms of the regulator of excitation-contraction and excitation-transcription coupling, calcium/calmodulin protein kinase II (CaMKII contribute to the specificity of myocellular calcium sensing between muscle types and whether concentration transients in its autophosphorylation can be simulated. CaMKII autophosphorylation at Thr287 was assessed in three muscle compartments of the rat after slow or fast motor unit-type stimulation and was compared against a computational model (CaMuZclE coupling myocellular calcium dynamics with CaMKII Thr287 phosphorylation. Qualitative differences existed between fast- (gastrocnemius medialis and slow-type muscle (soleus for the expression pattern of CaMKII isoforms. Phospho-Thr287 content of δA CaMKII, associated with nuclear functions, demonstrated a transient and compartment-specific increase after excitation, which contrasted to the delayed autophosphorylation of the sarcoplasmic reticulum-associated βM CaMKII. In soleus muscle, excitation-induced δA CaMKII autophosphorylation demonstrated frequency dependence (P = 0.02. In the glycolytic compartment of gastrocnemius medialis, CaMKII autophosphorylation after excitation was blunted. In silico assessment emphasized the importance of mitochondrial calcium buffer capacity for excitation-induced CaMKII autophosphorylation but did not predict its isoform specificity. The findings expose that CaMKII autophosphorylation with paced contractions is regulated in an isoform and muscle type-specific fashion and highlight properties emerging for phenotype-specific regulation of CaMKII.

Twenty-four-hour exposure to altered blood flow modifies endothelial Ca2+-activated K+ channels in rat mesenteric arteries

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Hilgers, Rob H P; Janssen, Ger M J; Fazzi, Gregorio E

2010-01-01

We tested the hypothesis that changes in arterial blood flow modify the function of endothelial Ca2+-activated K+ channels [calcium-activated K+ channel (K(Ca)), small-conductance calcium-activated K+ channel (SK3), and intermediate calcium-activated K+ channel (IK1)] before arterial structural...... remodeling. In rats, mesenteric arteries were exposed to increased [+90%, high flow (HF)] or reduced blood flow [-90%, low flow (LF)] and analyzed 24 h later. There were no detectable changes in arterial structure or in expression level of endothelial nitric-oxide synthase, SK3, or IK1. Arterial relaxing...... arteries, the balance between the NO/prostanoid versus EDHF response was unaltered. However, the contribution of IK1 to the EDHF response was enhanced, as indicated by a larger effect of TRAM-34 and a larger residual NS309-induced relaxation in the presence of UCL 1684. Reduction of blood flow selectively...

Effects of sodium bicarbonate and 1,25-dihydroxy-cholecalciferol on calcium and phosphorus balances in the rat

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Goulding, A.; McIntosh, J.; Campbell, D.

1984-01-01

Metabolic balance studies were undertaken to determine whether sodium bicarbonate (NaHCO 3 ) supplements (4.5 mmol/day) altered 7-day cumulative calcium (Ca) phosphorus (P) balances in growing rats consuming either a basal diet providing 0.6% Ca and 0.3% P, or this diet plus 1,25-dihydroxycholecalciferol [40 ng 1,25(OH) 2 D 3 /day]. Feeding bicarbonate lowered urinary Ca but raised fecal Ca so that Ca balance became less positive. However, 1,25(OH) 2 D 3 increased net absorption of Ca and P to the same degree when given to control rats and rats consuming bicarbonate. Nevertheless, bicarbonate-fed rats had lower net Ca absorption than controls, even when treated with high doses of 1,25(OH) 2 D 3 . Changes in net Ca absorption induced by bicarbonate may occur at a point in the gut distal to the duodenum since duodenal 45 Ca absorption was decreased by bicarbonate feeding. The present results show that bicarbonate consumption depressed net Ca absorption in the rat. The effect appears to be independent of changes in 1,25(OH) 2 D 3 metabolism because it is manifest in animals receiving high doses of 1,25(OH) 2 D 3 , which stimulate alimentary Ca absorption maximally, and because bicarbonate-fed rats are able to respond normally to exogenous 1,25(OH) 2 D 3 by increasing their net absorption of Ca and P. In view of this demonstration that NaHCO 3 supplements elevate fecal Ca loss in the rat, it is suggested that studies should be undertaken to determine whether bicarbonate exerts similar adverse effects on Ca balance in humans

The effect of erythropoietin on calcium levels during hypoxia reoxygenation injury in rats

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Constantinos Tsompos

2016-04-01

Full Text Available This experimental study examined the effect of erythropoietin (Epo on rat model and particularly in a hypoxia-reoxygenation protocol. The effect of that molecule was studied biochemically using blood mean calcium levels (Ca++. Forty rats of mean weight 247.7 g were used in the study. Ca++ levels were measured at 60 min (groups A and C and at 120 min (groups B and D of reoxygenation. Erythropoietin was administered only in groups C and D. Epo administration non-significantly decreased the Ca++ levels by 0.56%±1.13% (P=0.5761. Reoxygenation time non-significantly increased the Ca++ levels by 0.65%±1.12% (P=0.5281. However, Epo administration and reoxygenation time together non-significantly decreased the Ca++ levels by 0.34%±0.68% (P=0.6095. Epo administration whether it interacted or not with reoxygenation time had non-significant decreasing short-term effects on calcium levels. Perhaps, a longer study time than 2 h or a higher Epo dose may reveal more significant effects.

Attenuation of hypoxic current by intracellular applications of ATP regenerating agents in hippocampal CA1 neurons of rat brain slices.

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Chung, I; Zhang, Y; Eubanks, J H; Zhang, L

1998-10-01

Hypoxia-induced outward currents (hyperpolarization) were examined in hippocampal CA1 neurons of rat brain slices, using the whole-cell recording technique. Hypoxic episodes were induced by perfusing slices with an artificial cerebrospinal fluid aerated with 5% CO2/95% N2 rather than 5% CO2/95% O2, for about 3 min. The hypoxic current was consistently and reproducibly induced in CA1 neurons dialysed with an ATP-free patch pipette solution. This current manifested as an outward shift in the holding current in association with increased conductance, and it reversed at -78 +/- 2.5 mV, with a linear I-V relation in the range of -100 to -40 mV. To provide extra energy resources to individual neurons recorded, agents were added to the patch pipette solution, including MgATP alone, MgATP + phosphocreatine + creatine kinase, or MgATP + creatine. In CA1 neurons dialysed with patch solutions including these agents, hypoxia produced small outward currents in comparison with those observed in CA1 neurons dialysed with the ATP-free solution. Among the above agents examined, whole-cell dialysis with MgATP + creatine was the most effective at decreasing the hypoxic outward currents. We suggest that the hypoxic hyperpolarization is closely related to energy metabolism in individual CA1 neurons, and that the energy supply provided by phosphocreatine metabolism may play a critical role during transient metabolic stress.

Circulating FGF23 levels in response to acute changes in plasma Ca(2+)

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Gravesen, E; Mace, M.L.; Hofman-Bang, J.

2014-01-01

The regulation of fibroblast growth factor 23 (FGF23) synthesis and secretion is still incompletely understood. FGF23 is an important regulator of renal phosphate excretion and has regulatory effects on the calciotropic hormones calcitriol and parathyroid hormone (PTH). Calcium (Ca) and phosphate...... FGF23 levels and whether a close relationship, similar that known for Ca and PTH, exists between Ca and FGF23. Thus, the aim of the present study was to examine whether acute hypercalcemia and hypocalcemia regulate FGF23 levels in the rat. Acute hypercalcemia was induced by an intravenous Ca infusion...... and hypocalcemia by infusion of ethylene glycol tetraacetic acid (EGTA) in normal and acutely parathyroidectomized rats. Intact plasma FGF23 and intact plasma PTH and plasma Ca(2+) and phosphate were measured. Acute hypercalcemia and hypocalcemia resulted as expected in adequate PTH secretory responses. Plasma FGF...

Turmeric extract inhibits apoptosis of hippocampal neurons of trimethyltin-exposed rats.

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Yuliani, S; Widyarini, S; Mustofa; Partadiredja, G

2017-01-01

The aim of the present study was to reveal the possible antiapoptotic effect of turmeric (Curcuma longa Linn.) on the hippocampal neurons of rats exposed to trimethyltin (TMT). Oxidative damage in the hippocampus can induce the apoptosis of neurons associated with the pathogenesis of dementiaMETHODS. The ethanolic turmeric extract and a citicoline (as positive control) solution were administered to the TMT-exposed rats for 28 days. The body weights of rats were recorded once a week. The hippocampal weights and imumunohistochemical expression of caspase 3 proteins in the CA1 and CA2-CA3 regions of the hippocampi were examined at the end of the experiment. Immunohistochemical analysis showed that the injection of TMT increased the expression of caspase 3 in the CA1 and CA2-CA3 regions of hippocampus. TMT also decreased the body and hippocampal weights. Furthermore, the administration of 200 mg/kg bw dose of turmeric extract decreased the caspase 3 expression in the CA2-CA3 pyramidal neurons but not in the CA1 neurons. It also prevented the decrease of the body and hippocampal weights. We suggest that the 200 mg/kg bw dose of turmeric extract may exert antiapoptotic effect on the hippocampal neurons of the TMT-exposed rats (Tab. 1, Fig. 3, Ref. 49).

Caffeine and REM sleep deprivation: Effect on basal levels of signaling molecules in area CA1.

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Alkadhi, Karim A; Alhaider, Ibrahim A

2016-03-01

We have investigated the neuroprotective effect of chronic caffeine treatment on basal levels of memory-related signaling molecules in area CA1 of sleep-deprived rats. Animals in the caffeine groups were treated with caffeine in drinking water (0.3g/l) for four weeks before they were REM sleep-deprived for 24h in the Modified Multiple Platforms paradigm. Western blot analysis of basal protein levels of plasticity- and memory-related signaling molecules in hippocampal area CA1 showed significant down regulation of the basal levels of phosphorylated- and total-CaMKII, phosphorylated- and total-CREB as well as those of BDNF and CaMKIV in sleep deprived rats. All these changes were completely prevented in rats that chronically consumed caffeine. The present findings suggest an important neuroprotective property of caffeine in sleep deprivation. Copyright © 2016 Elsevier Inc. All rights reserved.

β adrenergic receptor/cAMP/PKA signaling contributes to the intracellular Ca2+ release by tentacle extract from the jellyfish Cyanea capillata.

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Wang, Qianqian; Zhang, Hui; Wang, Bo; Wang, Chao; Xiao, Liang; Zhang, Liming

2017-07-25

Intracellular Ca 2+ overload induced by extracellular Ca 2+ entry has previously been confirmed to be an important mechanism for the cardiotoxicity as well as the acute heart dysfunction induced by jellyfish venom, while the underlying mechanism remains to be elucidated. Under extracellular Ca 2+ -free or Ca 2+ -containing conditions, the Ca 2+ fluorescence in isolated adult mouse cardiomyocytes pre-incubated with tentacle extract (TE) from the jellyfish Cyanea capillata and β blockers was scanned by laser scanning confocal microscope. Then, the cyclic adenosine monophosphate (cAMP) concentration and protein kinase A (PKA) activity in primary neonatal rat ventricular cardiomyocytes were determined by ELISA assay. Furthermore, the effect of propranolol against the cardiotoxicity of TE was evaluated in Langendorff-perfused rat hearts and intact rats. The increase of intracellular Ca 2+ fluorescence signal by TE was significantly attenuated and delayed when the extracellular Ca 2+ was removed. The β adrenergic blockers, including propranolol, atenolol and esmolol, partially inhibited the increase of intracellular Ca 2+ in the presence of 1.8 mM extracellular Ca 2+ and completely abolished the Ca 2+ increase under an extracellular Ca 2+ -free condition. Both cAMP concentration and PKA activity were stimulated by TE, and were inhibited by the β adrenergic blockers. Cardiomyocyte toxicity of TE was antagonized by β adrenergic blockers and the PKA inhibitor H89. Finally, the acute heart dysfuction by TE was antagonized by propranolol in Langendorff-perfused rat hearts and intact rats. Our findings indicate that β adrenergic receptor/cAMP/PKA signaling contributes to the intracellular Ca 2+ overload through intracellular Ca 2+ release by TE from the jellyfish C. capillata.

Acacetin inhibits glutamate release and prevents kainic acid-induced neurotoxicity in rats.

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Tzu-Yu Lin

Full Text Available An excessive release of glutamate is considered to be a molecular mechanism associated with several neurological diseases that causes neuronal damage. Therefore, searching for compounds that reduce glutamate neurotoxicity is necessary. In this study, the possibility that the natural flavone acacetin derived from the traditional Chinese medicine Clerodendrum inerme (L. Gaertn is a neuroprotective agent was investigated. The effect of acacetin on endogenous glutamate release in rat hippocampal nerve terminals (synaptosomes was also investigated. The results indicated that acacetin inhibited depolarization-evoked glutamate release and cytosolic free Ca(2+ concentration ([Ca(2+]C in the hippocampal nerve terminals. However, acacetin did not alter synaptosomal membrane potential. Furthermore, the inhibitory effect of acacetin on evoked glutamate release was prevented by the Cav2.2 (N-type and Cav2.1 (P/Q-type channel blocker known as ω-conotoxin MVIIC. In a kainic acid (KA rat model, an animal model used for excitotoxic neurodegeneration experiments, acacetin (10 or 50 mg/kg was administrated intraperitoneally to the rats 30 min before the KA (15 mg/kg intraperitoneal injection, and subsequently induced the attenuation of KA-induced neuronal cell death and microglia activation in the CA3 region of the hippocampus. The present study demonstrates that the natural compound, acacetin, inhibits glutamate release from hippocampal synaptosomes by attenuating voltage-dependent Ca(2+ entry and effectively prevents KA-induced in vivo excitotoxicity. Collectively, these data suggest that acacetin has the therapeutic potential for treating neurological diseases associated with excitotoxicity.

Transplanted Bone Marrow Mesenchymal Stem Cells Improve Memory in Rat Models of Alzheimer's Disease

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Parvin Babaei

2012-01-01

Full Text Available The present study aims to evaluate the effect of bone marrow mesenchymal stem cells (MSCs grafts on cognition deficit in chemically and age-induced Alzheimer's models of rats. In the first experiments aged animals (30 months were tested in Morris water maze (MWM and divided into two groups: impaired memory and unimpaired memory. Impaired groups were divided into two groups and cannulated bilaterally at the CA1 of the hippocampus for delivery of mesenchymal stem cells (500×103/ and PBS (phosphate buffer saline. In the second experiment, Ibotenic acid (Ibo was injected bilaterally into the nucleus basalis magnocellularis (NBM of young rats (3 months and animals were tested in MWM. Then, animals with memory impairment received the following treatments: MSCs (500×103/ and PBS. Two months after the treatments, cognitive recovery was assessed by MWM in relearning paradigm in both experiments. Results showed that MSCs treatment significantly increased learning ability and memory in both age- and Ibo-induced memory impairment. Adult bone marrow mesenchymal stem cells show promise in treating cognitive decline associated with aging and NBM lesions.

Mechanisms of dendritic spine remodeling in a rat model of traumatic brain injury.

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Campbell, John N; Low, Brian; Kurz, Jonathan E; Patel, Sagar S; Young, Matt T; Churn, Severn B

2012-01-20

Traumatic brain injury (TBI), a leading cause of death and disability in the United States, causes potentially preventable damage in part through the dysregulation of neural calcium levels. Calcium dysregulation could affect the activity of the calcium-sensitive phosphatase calcineurin (CaN), with serious implications for neural function. The present study used both an in vitro enzymatic assay and Western blot analyses to characterize the effects of lateral fluid percussion injury on CaN activity and CaN-dependent signaling in the rat forebrain. TBI resulted in an acute alteration of CaN phosphatase activity and long-lasting alterations of its downstream effector, cofilin, an actin-depolymerizing protein. These changes occurred bilaterally in the neocortex and hippocampus, appeared to persist for hours after injury, and coincided with synapse degeneration, as suggested by a loss of the excitatory post-synaptic protein PSD-95. Interestingly, the effect of TBI on cofilin in some brain regions was blocked by a single bolus of the CaN inhibitor FK506, given 1 h post-TBI. Overall, these findings suggest a loss of synapse stability in both hemispheres of the laterally-injured brain, and offer evidence for region-specific, CaN-dependent mechanisms.

High-density expression of Ca2+-permeable ASIC1a channels in NG2 glia of rat hippocampus.

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Yen-Chu Lin

Full Text Available NG2 cells, a fourth type of glial cell in the mammalian CNS, undergo reactive changes in response to a wide variety of brain insults. Recent studies have demonstrated that neuronally expressed acid-sensing ion channels (ASICs are implicated in various neurological disorders including brain ischemia and seizures. Acidosis is a common feature of acute neurological conditions. It is postulated that a drop in pH may be the link between the pathological process and activation of NG2 cells. Such postulate immediately prompts the following questions: Do NG2 cells express ASICs? If so, what are their functional properties and subunit composition? Here, using a combination of electrophysiology, Ca2+ imaging and immunocytochemistry, we present evidence to demonstrate that NG2 cells of the rat hippocampus express high density of Ca2+-permeable ASIC1a channels compared with several types of hippocampal neurons. First, nucleated patch recordings from NG2 cells revealed high density of proton-activated currents. The magnitude of proton-activated current was pH dependent, with a pH for half-maximal activation of 6.3. Second, the current-voltage relationship showed a reversal close to the equilibrium potential for Na+. Third, psalmotoxin 1, a blocker specific for the ASIC1a channel, largely inhibited proton-activated currents. Fourth, Ca2+ imaging showed that activation of proton-activated channels led to an increase of [Ca2+]i. Finally, immunocytochemistry showed co-localization of ASIC1a and NG2 proteins in the hippocampus. Thus the acid chemosensor, the ASIC1a channel, may serve for inducing membrane depolarization and Ca2+ influx, thereby playing a crucial role in the NG2 cell response to injury following ischemia.

Age-related differences in the bone mineralization pattern of rats following exercise

International Nuclear Information System (INIS)

McDonald, R.; Hegenauer, J.; Saltman, P.

1986-01-01

The effect of 12 weeks of treadmill exercise on the mineralization of trabecular and cortical bone was studied in rats 7, 14, and 19 months of age. Bone mineralization was evaluated by measuring concentrations of Ca, Mg, and hydroxyproline as well as uptake of 45Ca concentration in the femur, humerus, rib and calvaria. The 7- and 14-month-old rats increased mineralization in those cortical bones directly involved in exercise. The 19-month animal responded to exercise by increasing mineralization in all bones examined, including the nonweight bearing trabecular calvaria and cortical rib. From these data, it is apparent that the older animals undergo a total skeletal mineralization in response to exercise compared with local adaptation in the younger animal. Further, we provide evidence to support the use of the rat as a model in which to study mammalian bone physiology during the aging process

Exercise preconditioning exhibits neuroprotective effects on hippocampal CA1 neuronal damage after cerebral ischemia

Institute of Scientific and Technical Information of China (English)

Nabi Shamsaei; Mehdi Khaksari; Sohaila Erfani; Hamid Rajabi; Nahid Aboutaleb

2015-01-01

Recent evidence has suggested the neuroprotective effects of physical exercise on cerebral isch-emic injury. However, the role of physical exercise in cerebral ischemia-induced hippocampal damage remains controversial. The aim of the present study was to evaluate the effects of pre-ischemia treadmill training on hippocampal CA1 neuronal damage after cerebral ischemia. Male adult rats were randomly divided into control, ischemia and exercise + ischemia groups. In the exercise + ischemia group, rats were subjected to running on a treadmill in a designated time schedule (5 days per week for 4 weeks). Then rats underwent cerebral ischemia induction th rough occlusion of common carotids followed by reperfusion. At 4 days after cerebral ischemia, rat learning and memory abilities were evaluated using passive avoidance memory test and rat hippocampal neuronal damage was detected using Nissl and TUNEL staining. Pre-ischemic ex-ercise signiifcantly reduced the number of TUNEL-positive cells and necrotic cell death in the hippocampal CA1 region as compared to the ischemia group. Moreover, pre-ischemic exercise significantly prevented ischemia-induced memory dysfunction. Pre-ischemic exercise mighct prevent memory deficits after cerebral ischemia through rescuing hippocampal CA1 neurons from ischemia-induced degeneration.

Zinc-induced cardiomyocyte relaxation in a rat model of hyperglycemia is independent of myosin isoform

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Yi Ting

2012-11-01

Full Text Available Abstract It has been reported previously that diabetic cardiomyopathy can be inhibited or reverted with chronic zinc supplementation. In the current study, we hypothesized that total cardiac calcium and zinc content is altered in early onset diabetes mellitus characterized in part as hyperglycemia (HG and that exposure of zinc ion (Zn2+ to isolated cardiomyocytes would enhance contraction-relaxation function in HG more so than in nonHG controls. To better control for differential cardiac myosin isoform expression as occurs in rodents after β-islet cell necrosis, hypothyroidism was induced in 16 rats resulting in 100% β-myosin heavy chain expression in the heart. β-Islet cell necrosis was induced in half of the rats by streptozocin administration. After 6 wks of HG, both HG and nonHG controls rats demonstrated similar myofilament performance measured as thin filament calcium sensitivity, native thin filament velocity in the myosin motility assay and contractile velocity and power. Extracellular Zn2+ reduced cardiomyocyte contractile function in both groups, but enhanced relaxation function significantly in the HG group compared to controls. Most notably, a reduction in diastolic sarcomere length with increasing pacing frequencies, i.e., incomplete relaxation, was more pronounced in the HG compared to controls, but was normalized with extracellular Zn2+ application. This is a novel finding implicating that the detrimental effect of HG on cardiomyocyte Ca2+ regulation can be amelioration by Zn2+. Among the many post-translational modifications examined, only phosphorylation of ryanodine receptor (RyR at S-2808 was significantly higher in HG compared to nonHG. We did not find in our hypothyroid rats any differentiating effects of HG on myofibrillar protein phosphorylation, lysine acetylation, O-linked N-acetylglucosamine and advanced glycated end-products, which are often implicated as complicating factors in cardiac performance due to HG. Our

The effects of CCK-8S on spatial memory and long-term potentiation at CA1 during induction of stress in rats.

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Sadeghi, Malihe; Reisi, Parham; Radahmadi, Maryam

2017-12-01

Cholecystokinin (CCK) has been proposed as a mediator in stress. However, it is still not fully documented what are its effects. We aimed to evaluate the effects of systemic administration of CCK exactly before induction of stress on spatial memory and synaptic plasticity at CA1 in rats. Male Wistar rats were divided into 4 groups: the control, the control-CCK, the stress and the stress-CCK. Restraint stress was induced 6 hr per day, for 24 days. Cholecystokinin sulfated octapeptide (CCK-8S) was injected (1.6 µg/kg, IP) before each session of stress induction. Spatial memory was evaluated by Morris water maze test. Long-term potentiation (LTP) in Schaffer collateral-CA1 synapses was assessed (by 100 Hz tetanization) in order to investigate synaptic plasticity. Stress impaired spatial memory significantly ( P stress group. With respect to the control group, both fEPSP amplitude and slope were significantly ( P stress group. However, there were no differences between responses of the control-CCK and Stress-CCK groups compared to the control group. The present results suggest that high levels of CCK-8S during induction of stress can modulate the destructive effects of stress on hippocampal synaptic plasticity and memory. Therefore, the mediatory effects of CCK in stress are likely as compensatory responses.

A sequential vesicle pool model with a single release sensor and a ca(2+)-dependent priming catalyst effectively explains ca(2+)-dependent properties of neurosecretion

DEFF Research Database (Denmark)

Walter, Alexander M; da Silva Pinheiro, Paulo César; Verhage, Matthijs

2013-01-01

identified. We here propose a Sequential Pool Model (SPM), assuming a novel Ca(2+)-dependent action: a Ca(2+)-dependent catalyst that accelerates both forward and reverse priming reactions. While both models account for fast fusion from the Readily-Releasable Pool (RRP) under control of synaptotagmin-1...... the simultaneous changes in release rate and amplitude seen when mutating the SNARE-complex. Finally, it can account for the loss of fast- and the persistence of slow release in the synaptotagmin-1 knockout by assuming that the RRP is depleted, leading to slow and Ca(2+)-dependent fusion from the NRP. We conclude...... that the elusive 'alternative Ca(2+) sensor' for slow release might be the upstream priming catalyst, and that a sequential model effectively explains Ca(2+)-dependent properties of secretion without assuming parallel pools or sensors....

Expression of calmodulin mRNA in rat olfactory neuroepithelium.

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Biffo, S; Goren, T; Khew-Goodall, Y S; Miara, J; Margolis, F L

1991-04-01

A calmodulin (CaM) cDNA was isolated by differential hybridization screening of a lambda gt10 library prepared from rat olfactory mucosa. This cDNA fragment, containing most of the open reading frame of the rat CaMI gene, was subcloned and used to characterize steady-state expression of CaM mRNA in rat olfactory neuroepithelium and bulb. Within the bulb mitral cells are the primary neuronal population expressing CaM mRNA. The major CaM mRNA expressed in the olfactory mucosa is 1.7 kb with smaller contributions from mRNAs of 4.0 and 1.4 kb. CaM mRNA was primarily associated with the olfactory neurons and, despite the cellular complexity of the tissue and the known involvement of CaM in diverse cellular processes, was only minimally evident in sustentacular cells, gland cells or respiratory epithelium. Following bulbectomy CaM mRNA declines in the olfactory neuroepithelium as does olfactory marker protein (OMP) mRNA. In contrast to the latter, CaM mRNA makes a partial recovery by one month after surgery. These results, coupled with those from in situ hybridization, indicate that CaM mRNA is expressed in both mature and immature olfactory neurons. The program regulating CaM gene expression in olfactory neurons is distinct from those controlling expression of B50/GAP43 in immature, or OMP in mature, neurons respectively.

Effects of benzo(a)pyrene exposure on the ATPase activity and calcium concentration in the hippocampus of neonatal rats.

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Yang, Kai; Chen, Chengzhi; Cheng, Shuqun; Cao, Xianqing; Tu, Baijie

2017-03-30

To investigate whether postnatal benzo(a)pyrene (B(a)P) exposure caused the impairments on the process of neurodevelopment and the alteration in the calcium medium in the neonatal rats. Eighty neonatal Sprague Dawley (SD) rats were randomly divided into 5 groups (untreated control group, vehicle group, 0.02 mg/kg, 0.2 mg/kg and 2 mg/kg B(a)P-exposed group). Rats were treated with B(a)P by the intragastric administration from postnatal day (PND) 4 to 25. Morris water maze (MWM) was employed to observe the spatial memory of rats. The activity of calcium adenosine triphosphatase (Ca2+-ATPase), sodium-potassium adenosine triphosphatase (Na+-K+-ATPase) and calcium-magnesium adenosine triphosphatase (Ca2+-Mg2+-ATPase) in the hippocampus were detected by commercial kits. Fura-2 pentakis(acetoxymethyl) (Fura-2/AM) probe and reactive oxygen species (ROS) reagent kit were used for measuring the concentration of Ca2+ and ROS in the hippocampus synapse, respectively. Rats exposed to B(a)P resulted in the deficits in the spatial memory manifested by the increased escape latency and decreased number of crossing platform and time spent in target quadrant in comparison with the control groups. Benzo(a)pyrene exposure caused the significant decrease in the ATPase activity in the hippocampus and caused Ca2+ overload in the synaptic, besides, the ROS concentration increased significantly which may further induce neurobehavioral impairment of the neonatal rats. Our findings suggest that postnatal B(a)P exposure may cause the neurobehavioral impairments in the neonatal rats, which were mediated by the decreased ATPase activity and elevated Ca2+ concentration. Int J Occup Med Environ Health 2017;30(2):203-211. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

Plasma hormonal profiles and dendritic spine density and morphology in the hippocampal CA1 stratum radiatum, evidenced by light microscopy, of virgin and postpartum female rats.

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Brusco, Janaína; Wittmann, Raul; de Azevedo, Márcia S; Lucion, Aldo B; Franci, Celso R; Giovenardi, Márcia; Rasia-Filho, Alberto A

2008-06-27

Successful reproduction requires that changes in plasma follicle-stimulating hormone (FSH), luteinizing hormone (LH), prolactin (PRL), oxytocin (OT), estrogen (E(2)) and progesterone (P(4)) occur together with the display of maternal behaviors. Ovarian steroids and environmental stimuli can affect the dendritic spines in the rat hippocampus. Here, studying Wistar rats, it is described: (a) the sequential and concomitant changes in the hormonal profile of females at postpartum days (PP) 4, 8, 12, 16, 20 and 24, comparing to estrous cycle referential values; (b) the dendritic spine density in the stratum radiatum of CA1 (CA1-SR) Golgi-impregnated neurons in virgin females across the estrous cycle and in multiparous age-matched ones; and (c) the proportion of different types of spines in the CA1-SR of virgin and postpartum females, both in diestrus. Plasma levels of gonadotrophins and ovarian hormones remained low along PP while LH increased and PRL decreased near the end of the lactating period. The lowest dendritic spine density was found in virgin females in estrus when compared to diestrus and proestrus phases or to postpartum females in diestrus (p0.4). There were no differences in the proportions of the different spine types in nulliparous and postpartum females (p>0.2). Results suggest that medium layer CA1-SR spines undergo rapid modifications in Wistar females across the estrous cycle (not quite comparable to Sprague-Dawley data or to hormonal substitutive therapy following ovariectomy), but persistent effects of motherhood on dendritic spine density and morphology were not found in this area.

Effect of short-term ornithine alpha-ketoglutarate pretreatment on intestinal ischemia-reperfusion in rats Efeitos do pré-tratamento em curto prazo com ornitina alfa-cetoglutarato na isquemia-reperfusão intestinal em ratos

OpenAIRE

Eduardo Silvio Gouveia Gonçalves; Camila Menezes Rabelo; Alberico Ximenes do Prado Neto; José Huygens Parente Garcia; Sérgio Botelho Guimarães; Paulo Roberto Leitão de Vasconcelos

2011-01-01

PURPOSE: To investigate the effects of preventive enteral administration of ornithine alpha-ketoglutarate (OKG) in an ischemia-reperfusion rat model. METHODS: Sixty rats were randomized into five groups (G1-G5, n = 12). Each group was divided into two subgroups (n = 6) and treated with calcium carbonate (CaCa) or OKG by gavage. Thirty minutes later, the animals were anesthetized with xylazine 15mg + ketamine 1mg ip and subjected to laparotomy. G1-G3 rats served as controls. Rats in groups G4 ...

The physiological response of obese rat model with rambutan peel extract treatment

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Sri Rahayu Lestari

2014-09-01

Full Text Available Objective: To determine body weight gain, expression of Igf-1 and Igf-1 receptor on obese rat model treated with rambutan peel extract (RPE as a physiological response. Methods: Normal and obese rat feed with normal and high calorie diet around 1 2 weeks and continued to treat with ellagic acid, RPE 15, 30 and 60 mg/kg body weight respectively. Physiological responses observed were weight gain and expression of Igf-1 with its receptor. Body weight of rat was weighed once per week. Expression of Igf-1 and igf-1R observed with fluorescence immunohistochemistry. The intensity of Igf-1 and Igf-1R expression was analysis using FSX-BSW software. Results: The lowest weight gain was obtained on obese rat model treated with RPE 30 mg/kg body weight. The expression of Igf-1 and Igf-1R were reduced on obese rat model treated with RPE compared with obese rat model of non treatment (P<0.05. The low expression of Igf-1 and Igf-1R was found on obese rat model treated with ellagic acid and RPE 30 mg/kg body weight. Conclusions: The RPE was effecting to the physiological response on obese rat model. The RPE 30 mg/kg body weight inhibited body weight gain and decreased the expression of Igf-1 and Igf- 1R of obese rat model.

Lowering glucose level elevates [Ca2+]i in hypothalamic arcuate nucleus NPY neurons through P/Q-type Ca2+ channel activation and GSK3β inhibition

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Chen, Yu; Zhou, Jun; Xie, Na; Huang, Chao; Zhang, Jun-qi; Hu, Zhuang-li; Ni, Lan; Jin, You; Wang, Fang; Chen, Jian-guo; Long, Li-hong

2012-01-01

Aim: To identify the mechanisms underlying the elevation of intracellular Ca2+ level ([Ca2+]i) induced by lowering extracellular glucose in rat hypothalamic arcuate nucleus NPY neurons. Methods: Primary cultures of hypothalamic arcuate nucleus (ARC) neurons were prepared from Sprague-Dawley rats. NPY neurons were identified with immunocytochemical method. [Ca2+]i was measured using fura-2 AM. Ca2+ current was recorded using whole-cell patch clamp recording. AMPK and GSK3β levels were measured using Western blot assay. Results: Lowering glucose level in the medium (from 10 to 1 mmol/L) induced a transient elevation of [Ca2+]i in ARC neurons, but not in hippocampal and cortical neurons. The low-glucose induced elevation of [Ca2+]i in ARC neurons depended on extracellular Ca2+, and was blocked by P/Q-type Ca2+channel blocker ω-agatoxin TK (100 nmol/L), but not by L-type Ca2+ channel blocker nifedipine (10 μmol/L) or N-type Ca2+channel blocker ω-conotoxin GVIA (300 nmol/L). Lowering glucose level increased the peak amplitude of high voltage-activated Ca2+ current in ARC neurons. The low-glucose induced elevation of [Ca2+]i in ARC neurons was blocked by the AMPK inhibitor compound C (20 μmol/L), and enhanced by the GSK3β inhibitor LiCl (10 mmol/L). Moreover, lowering glucose level induced the phosphorylation of AMPK and GSK3β, which was inhibited by compound C (20 μmol/L). Conclusion: Lowering glucose level enhances the activity of P/Q type Ca2+channels and elevates [Ca2+]i level in hypothalamic arcuate nucleus neurons via inhibition of GSK3β. PMID:22504905

The Effect of Rosa Damascena Extract on Expression of Neurotrophic Factors in the CA1 Neurons of Adult Rat Hippocampus Following Ischemia

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Seyedeh Farzaneh Moniri

2018-01-01

Full Text Available Ischemic stroke is an important cause of death and disability in the world. Brain ischemia causes damage to brain cell, and among brain neurons, pyramidal neurons of the hippocampal CA1 region are more susceptive to ischemic injury. Recent findings suggest that neurotrophic factors protect against ischemic cell death. A dietary component of Rosa damascene extract possibly is associated with expression of neurotrophic factors mRNA following ischemia, so it can have therapeutic effect on cerebral ischemia. The present study attempts to evaluate the neuroprotective effect of Rosa damascene extract on adult rat hippocampal neurons following ischemic brain injury. Forty-eight adult male Wistar rats (weighing 250±20 gr and ages 10-12 weeks used in this study, animals randomly were divided into 6 groups including Control, ischemia/ reperfusion (IR, vehicle and three treated groups (IR+0.5, 1, 2 mg/ml extract. Global ischemia was induced by bilateral common carotid arteries occlusion for 20 minutes. The treatment was done by different doses of Rosa damascena extract for 30 days. After 30 days cell death and gene expression in neurons of the CA1 region of the hippocampus were evaluated by Nissl staining and real time PCR assay. We found a significant decrease in NGF, BDNF and NT3 mRNA expression in neurons of CA1 region of the hippocampus in ischemia group compared to control group (P<0.0001. Our results also revealed that the number of dark neurons significantly increases in ischemia group compared to control group (P<0.0001. Following treatment with Rosa damascene extract reduced the number of dark neurons that was associated with NGF, NT3, and BDNF mRNA expression. All doses level had positive effects, but the most effective dose of Rosa damascena extract was 1 mg/ml. Our results suggest that neuroprotective activity of Rosa damascena can enhance hippocampal CA1 neuronal survival after global ischemia.

Cajaninstilbene acid relaxes rat renal arteries: roles of Ca2+ antagonism and protein kinase C-dependent mechanism.

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Dong-Mei Zhang

Full Text Available Cajaninstilbene acid (CSA is a major active component present in the leaves of Cajanus cajan (L. Millsp. The present study explores the underlying cellular mechanisms for CSA-induced relaxation in rat renal arteries. Vascular reactivity was examined in arterial rings that were suspended in a Multi Myograph System and the expression of signaling proteins was assessed by Western blotting method. CSA (0.1-10 µM produced relaxations in rings pre-contracted by phenylephrine, serotonin, 9, 11-dideoxy-9α, 11α-epoxymethanoprostaglandin F(2α (U46619, and 60 mM KCl. CSA-induced relaxations did not show difference between genders and were unaffected by endothelium denudation, nor by treatment with N(G-nitro-L-arginine methyl ester, indomethacin, ICI-182780, tetraethylammonium ion, BaCl(2, glibenclamide, 4-aminopyridine or propranolol. CSA reduced contraction induced by CaCl(2 (0.01-5 mM in Ca(2+-free 60 mM KCl solution and by 30 nM (--Bay K8644 in 15 mM KCl solution. CSA inhibited 60 mM KCl-induced Ca(2+ influx in smooth muscle of renal arteries. In addition, CSA inhibited contraction evoked by phorbol 12-myristate 13-acetate (PMA, protein kinase C agonist in Ca(2+-free Krebs solution. Moreover, CSA reduced the U46619- and PMA-induced phosphorylation of myosin light chain (MLC at Ser19 and myosin phosphatase target subunit 1 (MYPT1 at Thr853 which was associated with vasoconstriction. CSA also lowered the phosphorylation of protein kinase C (PKCδ at Thr505. In summary, the present results suggest that CSA relaxes renal arteries in vitro via multiple cellular mechanisms involving partial inhibition of calcium entry via nifedipine-sensitive calcium channels, protein kinase C and Rho kinase.

Calcium antagonistic effects of Chinese crude drugs: Preliminary investigation and evaluation by 45Ca

International Nuclear Information System (INIS)

Liu Ning; Yang Yuanyou; Mo Shangwu; Liao Jiali; Jin Jiannan

2005-01-01

Coronary and other diseases in cardiac or brain blood vessels are considered to be due to the excessive influx of Ca 2+ into cytoplasm. If Ca 2+ channels in cell membrane are blocked by medicines or other substances with considerable calcium antagonistic effects, these diseases might be cured or controlled. The influence of some Chinese crude drugs, including Crocus sativus, Carthamus tinctorius, Ginkgo biloba and Bulbus allii macrostemi on Ca 2+ influx in isolated rat aortas was investigated by using 45 Ca as a radioactive tracer, and their calcium antagonistic effects were evaluated. It can be noted that Ca 2+ uptake in isolated rat aorta rings in normal physiological status was not markedly altered by these drugs, whereas the Ca 2+ influxes induced by norepinephrine of 1.2 μmol/L and KCl of 100 mmol/L were significantly inhibited by Crocus, Carthamus and Bulbus in a concentration-dependent manner, but not by Ginkgo. The results show that extracellular Ca 2+ influx through receptor-operated Ca 2+ channels and potential-dependent Ca 2+ channels can be blocked by Crocus, Carthamus and Bulbus. This implies that these Chinese crude drugs have obvious calcium antagonistic effects

Thyroid hormone activates rat liver adenosine 5,-monophosphate-activated protein kinase: relation to CaMKKb, TAK1 and LKB1 expression and energy status.

Science.gov (United States)

Vargas, R; Ortega, Y; Bozo, V; Andrade, M; Minuzzi, G; Cornejo, P; Fernandez, V; Videla, L A

2013-01-01

AMP-activated protein kinase (AMPK) is a sensor of energy status supporting cellular energy homeostasis that may represent the metabolic basis for 3,3,,5-triiodo-L-thyronine (T3) liver preconditioning. Functionally transient hyperthyroid state induced by T3 (single dose of 0.1 mg/kg) in fed rats led to upregulation of mRNA expression (RT-PCR) and protein phosphorylation (Western blot) of hepatic AMPK at 8 to 36 h after treatment. AMPK Thr 172 phosphorylation induced by T3 is associated with enhanced mRNA expression of the upstream kinases Ca2+ -calmodulin-dependent protein kinase kinase-beta (CaMKKbeta) and transforming growth-factor-beta-activated kinase-1 (TAK1), with increased protein levels of CaMKKbeta and higher TAK1 phosphorylation, without changes in those of the liver kinase B1 (LKB1) signaling pathway. Liver contents of AMP and ADP were augmented by 291 percent and 44 percent by T3 compared to control values (p less than 0.05), respectively, whereas those of ATP decreased by 64% (p less than 0.05), with no significant changes in the total content of adenine nucleotides (AMP + ADP + ATP) at 24 h after T3 administration. Consequently, hepatic ATP/ADP content ratios exhibited 64 percent diminution (p less than 0.05) and those of AMP/ATP increased by 425 percent (p less than 0.05) in T3-treated rats over controls. It is concluded that in vivoT3 administration triggers liver AMPK upregulation in association with significant enhancements in AMPK mRNA expression, AMPK phosphorylation coupled to CaMKKbeta and TAK1 activation, and in AMP/ATP ratios, which may promote enhanced AMPK activity to support T3-induced energy consuming processes such as those of liver preconditioning.

Acoustic noise improves motor learning in spontaneously hypertensive rats, a rat model of attention deficit hyperactivity disorder.

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Söderlund, Göran B W; Eckernäs, Daniel; Holmblad, Olof; Bergquist, Filip

2015-03-01

The spontaneously hypertensive (SH) rat model of ADHD displays impaired motor learning. We used this characteristic to study if the recently described acoustic noise benefit in learning in children with ADHD is also observed in the SH rat model. SH rats and a Wistar control strain were trained in skilled reach and rotarod running under either ambient noise or in 75 dBA white noise. In other animals the effect of methylphenidate (MPH) on motor learning was assessed with the same paradigms. To determine if acoustic noise influenced spontaneous motor activity, the effect of acoustic noise was also determined in the open field activity paradigm. We confirm impaired motor learning in the SH rat compared to Wistar SCA controls. Acoustic noise restored motor learning in SH rats learning the Montoya reach test and the rotarod test, but had no influence on learning in Wistar rats. Noise had no effect on open field activity in SH rats, but increased corner time in Wistar. MPH completely restored rotarod learning and performance but did not improve skilled reach in the SH rat. It is suggested that the acoustic noise benefit previously reported in children with ADHD is shared by the SH rat model of ADHD, and the effect is in the same range as that of stimulant treatment. Acoustic noise may be useful as a non-pharmacological alternative to stimulant medication in the treatment of ADHD. Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.

Alterations in the Interplay between Neurons, Astrocytes and Microglia in the Rat Dentate Gyrus in Experimental Models of Neurodegeneration

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Daniele Lana

2017-09-01

Full Text Available The hippocampus is negatively affected by aging and neurodegenerative diseases leading to impaired learning and memory abilities. A diverse series of progressive modifications in the intercellular communication among neurons, astrocytes and microglia occur in the hippocampus during aging or inflammation. A detailed understanding of the neurobiological modifications that contribute to hippocampal dysfunction may reveal new targets for therapeutic intervention. The current study focussed on the interplay between neurons and astroglia in the Granule Layer (GL and the Polymorphic Layer (PL of the Dentate Gyrus (DG of adult, aged and LPS-treated rats. In GL and PL of aged and LPS-treated rats, astrocytes were less numerous than in adult rats. In GL of LPS-treated rats, astrocytes acquired morphological features of reactive astrocytes, such as longer branches than was observed in adult rats. Total and activated microglia increased in the aged and LPS-treated rats, as compared to adult rats. In the GL of aged and LPS-treated rats many neurons were apoptotic. Neurons decreased significantly in GL and PL of aged but not in rats treated with LPS. In PL of aged and LPS-treated rats many damaged neurons were embraced by microglia cells and were infiltrated by branches of astrocyte, which appeared to be bisecting the cell body, forming triads. Reactive microglia had a scavenging activity of dying neurons, as shown by the presence of neuronal debris within their cytoplasm. The levels of the chemokine fractalkine (CX3CL1 increased in hippocampal homogenates of aged rats and rats treated with LPS, and CX3CL1 immunoreactivity colocalized with activated microglia cells. Here we demonstrated that in the DG of aged and LPS-treated rats, astrocytes and microglia cooperate and participate in phagocytosis/phagoptosis of apoptotic granular neurons. The differential expression/activation of astroglia and the alteration of their intercommunication may be responsible for

Glucagon releases Ca2+ from a FCCP-sensitive pool

International Nuclear Information System (INIS)

Kraus-Friedmann, N.

1986-01-01

The effects of physiological levels of glucagon on Ca 2+ efflux were examined in the perfused rat liver. Two methods were used to estimate Ca 2+ efflux: (1) prior labeling of the Ca 2+ pools with 45 Ca 2+ , and (2) measurement of perfusate Ca 2+ with atomic absorption. According to both methods, glucagon administration at the physiological level evoked Ca 2+ release. In order to identify the hormone-sensitive Ca 2+ pool, a method employed by several laboratories was used. In this method, mitochondrial Ca 2+ is released by FCCP, (carbonyl-cyanide 4 (trifluoro/methoxy) phenylhydrazone), a mitochondrial uncoupler. The effect of hormones on Ca 2+ release after such uncoupler administration is measured. A decreased release is taken as an indication that the pool is entirely or partially mitochondrial. FCCP released 90 +/- 29 nmoles Ca 2+ /gr wet liver. Glucagon (5 x 10 -9 M) released 107 +/- 45 nmoles Ca 2+ /gr wet liver before and 26 +/- 9 nmoles Ca 2+ /gr wet liver after FCCP. These data indicate that glucagon releases Ca 2+ mostly from the mitochondria

Determination of trace elements in tissues of diabetic rats by INAA

International Nuclear Information System (INIS)

Tan Mingguang; Wang Yinsong; Qian Yine; Zhang Guilin

2000-01-01

By using streptozotocin (STZ) injection to induce model diabetic rats, instrumental neutron activation analysis was applied to analyze elemental; concentrations in liver, kidney and pancreas tissues in diabetes and control rats. Results obtained for As, Br, Ca, Co, Cl, Cu, Fe, Hg, Mg, Mn, Na, Rb, S, Se and Zn in those tissues show that some elemental contents in diabetic group change obviously when compared with those of the controls. The changes of elemental contents and their significance are discussed

Bursting response to current-evoked depolarization in rat CA1 pyramidal neurons is correlated with lucifer yellow dye coupling but not with the presence of calbindin-D28k

International Nuclear Information System (INIS)

Baimbridge, K.G.; Peet, M.J.; McLennan, H.; Church, J.

1991-01-01

Calbindin-D28k (CaBP) immunohistochemistry has been combined with electrophysiological recording and Lucifer Yellow (LY) cell identification in the CA1 region of the rat hippocampal formation. CaBP is shown to be contained within a distinct sub-population of CA1 pyramidal cells which is equivalent to the superficial layer described by Lorente de No (1934). The neurogenesis of these CaBP-positive neurons occurs 1-2 days later than the CaBP-negative neurons in the deep pyramidal cell layer, as shown by 3H-thymidine autoradiography. No correlation could be found between the presence or absence of CaBP and the type of electrophysiological response to current-evoked depolarizing pulses. The latter could be separated into bursting or non-bursting types, and the bursting-type response was nearly always found to be associated with the presence of LY dye coupling. Furthermore, when dye coupling involved three neurons, a characteristic pattern was observed which may represent the coupling of phenotypically identical neurons into distinct functional units within the CA1 pyramidal cell layer. In this particular case the three neurons were all likely to be CaBP-positive

Changes in hippocampal neurons and memory function during the developmental stage of newborn rats with hypoxic-ischemic encephalopathy

Institute of Scientific and Technical Information of China (English)

Chuanjun Liu; Yue Li; Huiying Gao

2006-01-01

BACKGROUND: Under the normal circumstance, there exist some synapses with inactive functions in central nervous system (CNS), but these functions are activated following nerve injury. At the early stage of brain injury, the abnormal functions of brain are varied, and they have very strong plasticity and are corrected easily.OBJECTTVE: To observe the changes of neuronal morphology in hippocampal CA1 region and memory function in newborn rats with hypoxic-ischemic encephalopathy(HIE) from ischemia 6 hours to adult.DESTGN: Completely randomized grouping, controlled experiment.SETTING: Taian Health Center for Women and Children; Taishan Medical College.MATERTALS: Altogether 120 seven-day-old Wistar rats, of clean grade, were provided by the Experimental Animal Center, Shandong University of Traditional Chinese Medicine. Synaptophysin (SYN) polyclonal antibody was provided by Maixin Biological Company, Fuzhou.METHODS: This experiment was carried out in the Laboratory of Morphology, Taishan Medical College between October 2000 and December 2003. ① The newborn rats were randomly divided into 2 groups: model group and control group, 60 rats in each group. Five rats were chosen from each group at postoperative 6 hours, 24hours, 72 hours, 7 days, 2 weeks and 3 weeks separately for immunohistochemical staining. Fifteen newborn rats were chosen from each group at postoperative 4 weeks and 2 months separately for testing memory ability(After test, 5 rats from each group were sacrificed and used for immunohistochemical staining) ② The right common carotid artery of newborn rats of model group was ligated under the sthetized status. After two hours of incubation, the rats were placed for 2 hours in a container filled with nitrogen oxygen atmosphere containing 0.08 volume fraction of oxygen, thus, HIE models were created; As for the newborn rats in the control group, only blood vessels were isolated, and they were not ligated and hypoxia-treated. ③Thalamencephal tissue

Melatonin, a potential effective protector in whole body γ-irradiated rats

International Nuclear Information System (INIS)

Tawfik, S.S; El-Nashar, D.E; Ahmed, M.M; Hanafy, Z.E

2010-01-01

Melatonin (N-acetyl-5-methoxytryptamine), the chief hormone of pineal gland, is widely distributed in animal kingdom. It is claimed for its antioxidant and free radical properties. The present study aimed to examine the radio protective potentiality and efficacy of melatonin against damages induced in whole body γ-irradiated rats. Animals received melatonin (10 mg/ kg body wt/ day) for 10 successive days pre-exposure to 3 Gy of γ-radiation (acute dose). Rats sacrificed at 10 and 20 days post the irradiation time. The results revealed that the prolonged administration of melatonin has ameliorated the radiation- induced depletion in brain, testis and serum glutathione (GSH) level and a decrease in serum glutathione peroxidase (GPX) activity when compared with their matched values in irradiated rats. In addition, remarkable decreases in the concentration of lipid peroxidation (LPO) product; malondialdhyde (MDA) was observed in brain, testis and serum of rats received melatonin pre-radiation exposure. As well as, significant decreases in disulphide glutathione (GSSG) were observed in serum.Histopathological examination of brain and testis showed that administration of melatonin pre-irradiation according to the present regimen has attenuated radiation induced tissue damages and improved tissue architecture. Cytogenetically, the chromosomal aberration (CA) assay in bone marrow pointed out a significant difference between rats received melatonin pre-irradiation and γ-irradiated rats in most CA types. Accordingly, it could be postulated the tissue diversity and cytogenetic impact of the administrated melatonin against acute ion syndrome in rat model.

A comparative study of myosin and its subunits in adult and neonatal-rat hearts and in rat heart cells from young and old cultures.

OpenAIRE

Ghanbari, H A; McCarl, R L

1980-01-01

A possible explanation for the decrease in myosin Ca2+-dependent ATPase activity as rat heart cells age in culture is presented. The subunit structure and enzyme kinetics of myosin from adult and neonatal rat hearts and from rat heart cells of young and old cultures are compared. These studies indicate that the loss in Ca-ATPase activity of myosin from older cultures was an intrinsic property of the myosin itself. Myofibrillar fractions from the indicated four sources showed no qualitative or...

Effects of hypergravic fields on serotonergic neuromodulation in the rat hippocampus.

Science.gov (United States)

Horrigan, D J; Fuller, C A; Horowitz, J M

1997-10-01

The effects of 7 day exposure to 2G fields on serotonergic modulation at two synapses on a hippocampal pathway were examined by recording dentate gyrus and CA1 pyramidal cell layer electrical activity. Serotonin decreased the amplitude of the population spike (synchronous action potentials in hundreds of neurons) in both the dentate gyrus and CA1 regions of rats exposed to 2G fields for 7 days. The inhibition, averaging 26 +/- 4% (mean +/- SEM) in the dentate gyrus and 80 +/- 5% in the CA1 region, was not significantly different from inhibitory responses observed in 1G controls. The 5-HT1A agonist 8-OH-DPAT mimicked this inhibition in the dentate and CA1 regions of 1G rats. 8-OH-DPAT responses were not affected by exposure to 2G fields. We conclude that the hippocampus contains surplus 5-HT receptors so that decreases in receptor density reported in receptor binding studies do not result in a decrease in modulatory capability. A model to account for the physiological pathway that relates gravitational field strength to 5-HT receptor density without changing the effectiveness of 5-HT neuromodulation is discussed.

Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak

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Sankaranarayanan, Rajiv; Li, Yatong; Greensmith, David J.; Eisner, David A.

2016-01-01

Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay.In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase.Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient.Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine.Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient. Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the

Age-related Changes in Lateral Entorhinal and CA3 Neuron Allocation Predict Poor Performance on Object Discrimination

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Andrew P. Maurer

2017-06-01

Full Text Available Age-related memory deficits correlate with dysfunction in the CA3 subregion of the hippocampus, which includes both hyperactivity and overly rigid activity patterns. While changes in intrinsic membrane currents and interneuron alterations are involved in this process, it is not known whether alterations in afferent input to CA3 also contribute. Neurons in layer II of the lateral entorhinal cortex (LEC project directly to CA3 through the perforant path, but no data are available regarding the effects of advanced age on LEC activity and whether these activity patterns update in response to environmental change. Furthermore, it is not known the extent to which age-related deficits in sensory discrimination relate to the inability of aged CA3 neurons to update in response to new environments. Young and aged rats were pre-characterized on a LEGO© object discrimination task, comparable to behavioral tests in humans in which CA3 hyperactivity has been linked to impairments. The cellular compartment analysis of temporal activity with fluorescence in situ hybridization for the immediate-early gene Arc was then used to identify the principal cell populations that were active during two distinct epochs of random foraging in different environments. This approach enabled the extent to which rats could discriminate two similar objects to be related to the ability of CA3 neurons to update across different environments. In both young and aged rats, there were animals that performed poorly on the LEGO object discrimination task. In the aged rats only, however, the poor performers had a higher percent of CA3 neurons that were active during random foraging in a novel environment, but this is not related to the ability of CA3 neurons to remap when the environment changed. Afferent neurons to CA3 in LEC, as identified with the retrograde tracer choleratoxin B (CTB, also showed a higher percentage of cells that were positive for Arc mRNA in aged poor performing rats

Structure-Activity Relationship Models for Rat Carcinogenesis and Assessing the Role Mutagens Play in Model Predictivity

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Carrasquer, C. Alex; Batey, Kaylind; Qamar, Shahid; Cunningham, Albert R.; Cunningham, Suzanne L.

2016-01-01

We previously demonstrated that fragment based cat-SAR carcinogenesis models consisting solely of mutagenic or non-mutagenic carcinogens varied greatly in terms of their predictive accuracy. This led us to investigate how well the rat cancer cat-SAR model predicted mutagens and non-mutagens in their learning set. Four rat cancer cat-SAR models were developed: Complete Rat, Transgender Rat, Male Rat, and Female Rat, with leave-one-out (LOO) validation concordance values of 69%, 74%, 67%, and 73%, respectively. The mutagenic carcinogens produced concordance values in the range of 69–76% as compared to only 47–53% for non-mutagenic carcinogens. As a surrogate for mutagenicity comparisons between single site and multiple site carcinogen SAR models was analyzed. The LOO concordance values for models consisting of 1-site, 2-site, and 4+-site carcinogens were 66%, 71%, and 79%, respectively. As expected, the proportion of mutagens to non-mutagens also increased, rising from 54% for 1-site to 80% for 4+-site carcinogens. This study demonstrates that mutagenic chemicals, in both SAR learning sets and test sets, are influential in assessing model accuracy. This suggests that SAR models for carcinogens may require a two-step process in which mutagenicity is first determined before carcinogenicity can be accurately predicted. PMID:24697549

The effect of methylglyoxal-bis(guanylhydrazone) on mitochondrial Ca(2+) fluxes.

Science.gov (United States)

Salvi, Mauro; Toninello, Antonio

2002-01-15

Methylglyoxal-bis(guanylhydrazone) (MGBG) induces a dose-dependent inhibition of the electrophoretic Ca(2+) uptake by rat liver mitochondria (RLM) without affecting the electrical membrane potential. MGBG is also able to inhibit the electroneutral Ca(2+) release from mitochondria. These effects result in a progressive increase of Ca(2+) level in suspending medium indicating that Ca(2+) uptake is inhibited at higher extent than Ca(2+) efflux. Spermine instead, induces a lowering of external Ca(2+) concentration. This action is reversed by MGBG which again raises the external Ca(2+) concentration then in the absence of spermine, though at a lower extent. The mechanism of MGBG effects and their implications on energy metabolism are discussed.

Moringa oleifera-rich diet and T cell calcium signaling in spontaneously hypertensive rats.

Science.gov (United States)

Attakpa, E S; Bertin, G A; Chabi, N W; Ategbo, J-M; Seri, B; Khan, N A

2017-11-24

Moringa oleifera is a plant whose fruits, roots and leaves have been advocated for traditional medicinal uses. The physicochemical analysis shows that Moringa oleifera contains more dietary polyunsaturated fatty acids (PUFA) than saturated fatty acids (SFA). The consumption of an experimental diet enriched with Moringa oleifera extracts lowered blood pressure in spontaneously hypertensive rats (SHR), but not in normotensive Wistar-Kyoto (WKY) rats as compared to rats fed an unsupplemented control diet. Anti-CD3-stimulated T cell proliferation was diminished in both strains of rats fed the Moringa oleifera. The experimental diet lowered secretion of interleukin-2 in SHR, but not in WKY rats compared with rats fed the control diet. Studies of platelets from patients with primary hypertension and from SHR support the notion that the concentration of intracellular free calcium [Ca(2+)](i) is modified in both clinical and experimental hypertension. We observed that the basal, [Ca(2+)](i) was lower in T cells of SHR than in those of WKY rats fed the control diet. Feeding the diet with Moringa oleifera extracts to WKY rats did not alter basal [Ca(2+)](i) in T cells but increased basal [Ca(2+)](i) in SHR. Our study clearly demonstrated that Moringa oleifera exerts antihypertensive effects by inhibiting the secretion of IL-2 and modulates T cell calcium signaling in hypertensive rats.

Effect of environmental enrichment exposure on neuronal morphology of streptozotocin-induced diabetic and stressed rat hippocampus

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Narendra Pamidi

2014-08-01

Full Text Available Background: Environmental enrichment (EE exposure is known to influence the structural changes in the neuronal network of hippocampus. In the present study, we evaluated the effects of EE exposure on the streptozotocin (STZ-induced diabetic and stressed rat hippocampus. Methods: Male albino rats of Wistar strain (4-5 weeks old were grouped into normal control (NC, vehicle control (VC, diabetes (DI, diabetes + stress (DI + S, diabetes + EE (DI + E, and diabetes + stress + EE (DI + S + E groups (n = 8 in each group. Rats were exposed to stress and EE after inducing diabetes with STZ (40 mg/kg. Rats were sacrificed on Day 30 and brain sections were processed for cresyl violet staining to quantify the number of surviving neurons in the CA1, CA3, and dentate hilus (DH regions of hippocampus. Results: A significant (p < 0.001 decrease in the number of survived neurons was noticed in DI (CA1, 34.06 ± 3.2; CA3, 36.1 ± 3.62; DH, 9.83 ± 2.02 as well as DI + S (CA1, 14.03 ± 3.12; CA3, 20.27 ± 4.09; DH, 6.4 ± 1.21 group rats compared to NC rats (CA1, 53.64 ± 2.96; CA3, 62.1 ± 3.34; DH, 21.11 ± 1.03. A significant (p < 0.001 increase in the number of survived neurons was observed in DI + E (CA1, 42.3 ± 3.66; CA3, 46.73 ± 4.74; DH, 17.03 ± 2.19 and DI + S + E (CA1, 29.69 ± 4.47; CA3, 36.73 ± 3.89; DH, 12.23 ± 2.36 group rats compared to DI and DI + S groups, respectively. Conclusions: EE exposure significantly reduced the amount of neuronal damage caused by complications of diabetes and stress to the neurons of hippocampus.

The cumulative analgesic effect of repeated electroacupuncture involves synaptic remodeling in the hippocampal CA3 region☆

Science.gov (United States)

Xu, Qiuling; Liu, Tao; Chen, Shuping; Gao, Yonghui; Wang, Junying; Qiao, Lina; Liu, Junling

2012-01-01

In the present study, we examined the analgesic effect of repeated electroacupuncture at bilateral Zusanli (ST36) and Yanglingquan (GB34) once a day for 14 consecutive days in a rat model of chronic sciatic nerve constriction injury-induced neuropathic pain. In addition, concomitant changes in calcium/calmodulin-dependent protein kinase II expression and synaptic ultrastructure of neurons in the hippocampal CA3 region were examined. The thermal pain threshold (paw withdrawal latency) was increased significantly in both groups at 2 weeks after electroacupuncture intervention compared with 2 days of electroacupuncture. In ovariectomized rats with chronic constriction injury, the analgesic effect was significantly reduced. Electroacupuncture for 2 weeks significantly diminished the injury-induced increase in synaptic cleft width and thinning of the postsynaptic density, and it significantly suppressed the down-regulation of intracellular calcium/calmodulin-dependent protein kinase II expression in the hippocampal CA3 region. Repeated electroacupuncture intervention had a cumulative analgesic effect on injury-induced neuropathic pain reactions, and it led to synaptic remodeling of hippocampal neurons and upregulated calcium/calmodulin-dependent protein kinase II expression in the hippocampal CA3 region. PMID:25657670

Reduced endogenous Ca2+ buffering speeds active zone Ca2+ signaling.

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Delvendahl, Igor; Jablonski, Lukasz; Baade, Carolin; Matveev, Victor; Neher, Erwin; Hallermann, Stefan

2015-06-09

Fast synchronous neurotransmitter release at the presynaptic active zone is triggered by local Ca(2+) signals, which are confined in their spatiotemporal extent by endogenous Ca(2+) buffers. However, it remains elusive how rapid and reliable Ca(2+) signaling can be sustained during repetitive release. Here, we established quantitative two-photon Ca(2+) imaging in cerebellar mossy fiber boutons, which fire at exceptionally high rates. We show that endogenous fixed buffers have a surprisingly low Ca(2+)-binding ratio (∼ 15) and low affinity, whereas mobile buffers have high affinity. Experimentally constrained modeling revealed that the low endogenous buffering promotes fast clearance of Ca(2+) from the active zone during repetitive firing. Measuring Ca(2+) signals at different distances from active zones with ultra-high-resolution confirmed our model predictions. Our results lead to the concept that reduced Ca(2+) buffering enables fast active zone Ca(2+) signaling, suggesting that the strength of endogenous Ca(2+) buffering limits the rate of synchronous synaptic transmission.

17β Estradiol increases resilience and improves hippocampal synaptic function in helpless ovariectomized rats

Science.gov (United States)

Bredemann, Teruko M.; McMahon, Lori L.

2014-01-01

Summary Memory impairment is the most commonly reported cognitive symptom associated with major depressive disorder. Decreased hippocampal volume and neurogenesis in depression link hippocampal dysfunction with deficits in memory. Stress decreases hippocampal dendritic spine density and long-term potentiation (LTP) at glutamate synapses, a cellular correlate of learning and memory. However, elevated plasma levels of 17β estradiol (E2) during proestrus increase hippocampal structure and function, directly opposing the negative consequences of stress. In women, significant fluctuations in ovarian hormones likely increase vulnerability of hippocampal circuits to stress, potentially contributing to the greater incidence of depression compared to men. Using the learned helplessness model of depression and ovariectomized female rats, we investigated whether acquisition of helplessness and hippocampal synaptic dysfunction is differentially impacted by the presence or absence of plasma E2. We find that inescapable shock induces a greater incidence of helplessness in vehicle- versus E2-treated OVX rats. In the vehicle-treated group, LTP was absent at CA3-CA1 synapses in slices only from helpless rats, and CA1 spine density was decreased compared to resilient rats. In contrast, significant LTP was observed in slices from E2-treated helpless rats; importantly, spine density was not different between E2-treated helpless and resilient rats, dissociating spine density from the LTP magnitude. We also find that E2 replacement can reverse previously established helpless behavior. Thus, our results show that E2 replacement in OVX rats increases resilience and improves hippocampal plasticity, suggesting that E2 therapy may increase resilience to stress and preserve hippocampal function in women experiencing large fluctuations in plasma estrogen levels. PMID:24636504

Remodeling of hippocampal spine synapses in the rat learned helplessness model of depression.

Science.gov (United States)

Hajszan, Tibor; Dow, Antonia; Warner-Schmidt, Jennifer L; Szigeti-Buck, Klara; Sallam, Nermin L; Parducz, Arpad; Leranth, Csaba; Duman, Ronald S

2009-03-01

Although it has been postulated for many years that depression is associated with loss of synapses, primarily in the hippocampus, and that antidepressants facilitate synapse growth, we still lack ultrastructural evidence that changes in depressive behavior are indeed correlated with structural synaptic modifications. We analyzed hippocampal spine synapses of male rats (n=127) with electron microscopic stereology in association with performance in the learned helplessness paradigm. Inescapable footshock (IES) caused an acute and persistent loss of spine synapses in each of CA1, CA3, and dentate gyrus, which was associated with a severe escape deficit in learned helplessness. On the other hand, IES elicited no significant synaptic alterations in motor cortex. A single injection of corticosterone reproduced both the hippocampal synaptic changes and the behavioral responses induced by IES. Treatment of IES-exposed animals for 6 days with desipramine reversed both the hippocampal spine synapse loss and the escape deficit in learned helplessness. We noted, however, that desipramine failed to restore the number of CA1 spine synapses to nonstressed levels, which was associated with a minor escape deficit compared with nonstressed control rats. Shorter, 1-day or 3-day desipramine treatments, however, had neither synaptic nor behavioral effects. These results indicate that changes in depressive behavior are associated with remarkable remodeling of hippocampal spine synapses at the ultrastructural level. Because spine synapse loss contributes to hippocampal dysfunction, this cellular mechanism may be an important component in the neurobiology of stress-related disorders such as depression.

PGC-1α accelerates cytosolic Ca2+ clearance without disturbing Ca2+ homeostasis in cardiac myocytes

International Nuclear Information System (INIS)

Chen, Min; Wang, Yanru; Qu, Aijuan

2010-01-01

Energy metabolism and Ca 2+ handling serve critical roles in cardiac physiology and pathophysiology. Peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) is a multi-functional coactivator that is involved in the regulation of cardiac mitochondrial functional capacity and cellular energy metabolism. However, the regulation of PGC-1α in cardiac Ca 2+ signaling has not been fully elucidated. To address this issue, we combined confocal line-scan imaging with off-line imaging processing to characterize calcium signaling in cultured adult rat ventricular myocytes expressing PGC-1α via adenoviral transduction. Our data shows that overexpressing PGC-1α improved myocyte contractility without increasing the amplitude of Ca 2+ transients, suggesting that myofilament sensitivity to Ca 2+ increased. Interestingly, the decay kinetics of global Ca 2+ transients and Ca 2+ waves accelerated in PGC-1α-expressing cells, but the decay rate of caffeine-elicited Ca 2+ transients showed no significant change. This suggests that sarcoplasmic reticulum (SR) Ca 2+ -ATPase (SERCA2a), but not Na + /Ca 2+ exchange (NCX) contribute to PGC-1α-induced cytosolic Ca 2+ clearance. Furthermore, PGC-1α induced the expression of SERCA2a in cultured cardiac myocytes. Importantly, overexpressing PGC-1α did not disturb cardiac Ca 2+ homeostasis, because SR Ca 2+ load and the propensity for Ca 2+ waves remained unchanged. These data suggest that PGC-1α can ameliorate cardiac Ca 2+ cycling and improve cardiac work output in response to physiological stress. Unraveling the PGC-1α-calcium handing pathway sheds new light on the role of PGC-1α in the therapy of cardiac diseases.

Effects on atrial fibrillation in aged hypertensive rats by Ca(2+)-activated K(+) channel inhibition

DEFF Research Database (Denmark)

Diness, Jonas Goldin; Skibsbye, Lasse; Jespersen, Thomas

2011-01-01

We have shown previously that inhibition of small conductance Ca(2+)-activated K(+) (SK) channels is antiarrhythmic in models of acutely induced atrial fibrillation (AF). These models, however, do not take into account that AF derives from a wide range of predisposing factors, the most prevalent ...

Oxidative stress of crystalline lens in rat menopausal model.

Science.gov (United States)

Acer, Semra; Pekel, Gökhan; Küçükatay, Vural; Karabulut, Aysun; Yağcı, Ramazan; Çetin, Ebru Nevin; Akyer, Şahika Pınar; Şahin, Barbaros

2016-01-01

To evaluate lenticular oxidative stress in rat menopausal models. Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1). From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2), 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3), and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4). Total oxidant status (TOS), total antioxidant capacity (TAC), and oxidative stress index (OSI) measurements of the crystalline lenses were analyzed. The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05). The mean TOS values were similar between the groups (p >0.05), whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001). Our results indicate that menopause may not promote cataract formation.

Dietary Whey and Casein Differentially Affect Energy Balance, Gut Hormones, Glucose Metabolism, and Taste Preference in Diet-Induced Obese Rats.

Science.gov (United States)

Pezeshki, Adel; Fahim, Andrew; Chelikani, Prasanth K

2015-10-01

Dietary whey and casein proteins decrease food intake and body weight and improve glycemic control; however, little is known about the underlying mechanisms. We determined the effects of dietary whey, casein, and a combination of the 2 on energy balance, hormones, glucose metabolism, and taste preference in rats. In Expt. 1, Obesity Prone CD (OP-CD) rats were fed a high-fat control diet (33% fat energy) for 8 wk, and then randomly assigned to 4 isocaloric dietary treatments (n = 12/group): the control treatment (CO; 14% protein energy from egg white), the whey treatment (WH; 26% whey + 14% egg white), the casein treatment (CA; 26% casein + 14% egg white), or the whey plus casein treatment (WHCA; 13% whey + 13% casein + 14% egg white) for 28 d. Measurements included food intake, energy expenditure, body composition, metabolic hormones, glucose tolerance and key tissue markers of glucose and energy metabolism. In Expt. 2, naïve OP-CD rats were randomly assigned to 3 groups (n = 8/group). During an 8 d conditioning period, each group received on alternate days either the CO or WH, CO or CA, or CO or WHCA. Subsequently, preferences for the test diets were assessed on 2 consecutive days with food intake measurements at regular intervals. In Expt. 1, food intake was decreased by 17-37% for the first 14 d in the WH and CA rats, and by 18-34% only for the first 4 d in the WHCA compared with the CO rats. Fat mass decreased by 21-28% for the WH rats and 17-33% for the CA rats from day 14 onward, but by 30% only on day 28 in WHCA rats, relative to CO rats. Thus, food intake, body weight, and fat mass decreased more rapidly in WH and CA rats than in WHCA rats. Energy expenditure in WH rats decreased for the first 4 d compared with CA and WHCA rats, and for the first 7 d compared with the CO rats. Circulating leptin, glucose-dependent insulinotropic polypeptide, interleukin 6, and glucose concentrations were lower in WH, CA, and WHCA rats than in CO rats. Plasma glucagon

Thrombolytic and anticoagulation treatment in a rat embolic stroke model

DEFF Research Database (Denmark)

Rasmussen, Rune Skovgaard; Overgaard, K; Meden, P

2003-01-01

OBJECTIVES: The effects of pentasaccharide (PENTA), given alone or combined with thrombolysis using recombinant tissue plasminogen activator (rt-PA), on infarct size and clinical outcome were evaluated in a rat embolic stroke model. MATERIALS AND METHODS: Ninety-two rats were embolized unilateral...... alone or combined with rt-PA did not significantly increase mortality or tendency for hemorrhage.......OBJECTIVES: The effects of pentasaccharide (PENTA), given alone or combined with thrombolysis using recombinant tissue plasminogen activator (rt-PA), on infarct size and clinical outcome were evaluated in a rat embolic stroke model. MATERIALS AND METHODS: Ninety-two rats were embolized unilaterally...

Lewis and Fischer 344 rats as a model for genetic differences in spatial learning and memory: Cocaine effects.

Science.gov (United States)

Fole, Alberto; Miguéns, Miguel; Morales, Lidia; González-Martín, Carmen; Ambrosio, Emilio; Del Olmo, Nuria

2017-06-02

Lewis (LEW) and Fischer 344 (F344) rats are considered a model of genetic vulnerability to drug addiction. We previously showed important differences in spatial learning and memory between them, but in contrast with previous experiments demonstrating cocaine-induced enhanced learning in Morris water maze (MWM) highly demanding tasks, the eight-arm radial maze (RAM) performance was not modified either in LEW or F344 rats after chronic cocaine treatment. In the present work, chronically cocaine-treated LEW and F344 adult rats have been evaluated in learning and memory performance using the Y-maze, two RAM protocols that differ in difficulty, and a reversal protocol that tests cognitive flexibility. After one of the RAM protocols, we quantified dendritic spine density in hippocampal CA1 neurons and compared it to animals treated with cocaine but not submitted to RAM. LEW cocaine treated rats showed a better performance in the Y maze than their saline counterparts, an effect that was not evident in the F344 strain. F344 rats significantly took more time to learn the RAM task and made a greater number of errors than LEW animals in both protocols tested, whereas cocaine treatment induced deleterious effects in learning and memory in the highly difficult protocol. Moreover, hippocampal spine density was cocaine-modulated in LEW animals whereas no effects were found in F344 rats. We propose that differences in addictive-like behavior between LEW and F344 rats could be related to differences in hippocampal learning and memory processes that could be on the basis of individual vulnerability to cocaine addiction. Copyright © 2017 Elsevier Inc. All rights reserved.

Na+/Ca2+ exchange inhibitor, KB-R7943, attenuates contrast-induced acute 
kidney injury.

Science.gov (United States)

Yang, Dingwei; Yang, Dingping; Jia, Ruhan; Tan, Jin

2013-01-01

Intracellular Ca2+ overload is considered to be a key factor in contrast-induced acute kidney injury (CI-AKI). The Na+/Ca2+ exchanger (NCX) system is one of the main pathways of intracellular Ca2+ overload. We investigated the effects of KB-R7943, an inhibitor of the reverse mode of NCX, on CI-AKI in a rat model. Rats were divided into control group, CI-AKI group and pretreatment groups (with KB-R7943 dose of 5 or 10 mg/kg). CI-AKI was induced by diatrizoate administration in rats with cholesterol-supplemented diet for 8 weeks. Renal function and renal hemodynamics were determined 1 day following contrast medium administration. Renal histopathology was observed by light microscope. Renal tubular apoptosis was examined by TUNEL. Renal endothelin-1 (ET-1) was measured by radioimmunoassay. Renal malondialdehyde (MDA) and catalase (CAT) were measured as oxidative markers. Levels of serum creatinine (Scr), renal ET-1, MDA and CAT, and resistance index (RI) of renal blood vessels increased significantly in CI-AKI rats. The 
increases in Scr and RI of renal blood vessels induced by diatrizoate were suppressed significantly and 
dose-dependently by pretreatment with KB-R7943. Histopathological and TUNEL results showed that 
the contrast medium-induced severe renal tubular 
necrosis and apoptosis were significantly and dose-dependently attenuated by KB-R7943. KB-R7943 significantly suppressed the increment of renal ET-1 content and MDA and CAT level induced by contrast medium administration. Activation of the reverse mode of NCX, followed by ET-1 overproduction and increased oxidative stress, seems to play an important role in the pathogenesis of CI-AKI. The inhibitor of the reverse mode of NCX, KB-R7943, has renoprotective effects on CI-AKI.

ENU mutagenesis to generate genetically modified rat models

NARCIS (Netherlands)

van Boxtel, R.; Gould, M.; Cuppen, E.; Smits, B.M.

2010-01-01

The rat is one of the most preferred model organisms in biomedical research and has been extremely useful for linking physiology and pathology to the genome. However, approaches to genetically modify specific genes in the rat germ line remain relatively scarce. To date, the most efficient approach

Hypothalamic CaMKKβ mediates glucagon anorectic effect and its diet-induced resistance

Science.gov (United States)

Quiñones, Mar; Al-Massadi, Omar; Gallego, Rosalía; Fernø, Johan; Diéguez, Carlos; López, Miguel; Nogueiras, Ruben

2015-01-01

Objective Glucagon receptor antagonists and humanized glucagon antibodies are currently studied as promising therapies for obesity and type II diabetes. Among its variety of actions, glucagon reduces food intake, but the molecular mechanisms mediating this effect as well as glucagon resistance are totally unknown. Methods Glucagon and adenoviral vectors were administered in specific hypothalamic nuclei of lean and diet-induced obese rats. The expression of neuropeptides controlling food intake was performed by in situ hybridization. The regulation of factors of the glucagon signaling pathway was assessed by western blot. Results The central injection of glucagon decreased feeding through a hypothalamic pathway involving protein kinase A (PKA)/Ca2+-calmodulin-dependent protein kinase kinase β (CaMKKβ)/AMP-activated protein kinase (AMPK)-dependent mechanism. More specifically, the central injection of glucagon increases PKA activity and reduces protein levels of CaMKKβ and its downstream target phosphorylated AMPK in the hypothalamic arcuate nucleus (ARC). Consistently, central glucagon significantly decreased AgRP expression. Inhibition of PKA and genetic activation of AMPK in the ARC blocked glucagon-induced anorexia in lean rats. Genetic down-regulation of glucagon receptors in the ARC stimulates fasting-induced hyperphagia. Although glucagon was unable to decrease food intake in DIO rats, glucagon sensitivity was restored after inactivation of CaMKKβ, specifically in the ARC. Thus, glucagon decreases food intake acutely via PKA/CaMKKβ/AMPK dependent pathways in the ARC, and CaMKKβ mediates its obesity-induced hypothalamic resistance. Conclusions This work reveals the molecular underpinnings by which glucagon controls feeding that may lead to a better understanding of disease states linked to anorexia and cachexia. PMID:26909312

Mg,Ca-ATPase activity under irradiation

International Nuclear Information System (INIS)

Ladutin, V.V.; Orlova, V.V.; Lob, P.A.; Gerasiminko, I.V.; Mack, E.I.

2003-01-01

Full text: The influence of different doses irradiation at the Mg,Ca-ATPase activity at the rat brain has been investigated. The analyses were made at the apparatus of LKB and Carl-Ceis-Jena firm with help of reagents of Sigma and Boehringer firm. Rats decapitated after 1, 3, 6, 24 and 48 h after action of irradiation. Dose 0.206 C/kg. Erythrocytes. 1 and 3h after irradiation influence- decrease of Mg,Ca-ATPase activity to 86-87% relatively control level, 24 and 48 h - increase of activity to the control level. Dose 0.312 C/kg. Large hemispheres. 1h - decrease of ATPase activity to 90% relatively control, 3h - increase to control level, 24h - fall to 86%, after 48h small increase to 93% relatively control. Dose 9.287 C/kg. Large hemispheres. 1h - sharp fall of Mg, Ca-ATPase activity to 67 % relatively control, increase of activity to 96% after 3h and sharp fall of activity to 64% 6h after action of irradiation. Dose 9.287 C/kg. Cerebellum. 1h - sharp decrease of ATPase activity to 80%. After 3h -sharp increase to 160% relatively control level and sharp fall of ATPase activity to 47% relatively control after 6h. The mechanism of radiation pathology of active ion transport has been discussed

Biological action of 239Pu during its administration to rats by inhalation and Zn- or CaDTPA- complexone therapy

International Nuclear Information System (INIS)

Sinyakov, E.G.; Nifatov, A.P.; Lyubchanskij, Eh.R.; Bazhin, A.G.

1988-01-01

The authors described the effect of substantial amounts of plutonium nitrate administered to rats by inhalation in the presence of Zn- or CaDTPA-complexone therapy for 2 months. A 2-fold decrease of absorbed doses in the lung, a 3-fold decrease in the skeleton and a 4-fold decrease in the liver were shown. The mean life span of the treated animals was considerably raised. A significant reduction of the frequency of development of severe pneumosclerosis and an increase in the frequency of lung tumor development were noted. In view of the above, complexone therapy should be necessarily recommended during inhalation of radionucleides in austantial ammounts

Glucocorticoid receptor activation is involved in producing abnormal phenotypes of single-prolonged stress rats: a putative post-traumatic stress disorder model.

Science.gov (United States)

Kohda, K; Harada, K; Kato, K; Hoshino, A; Motohashi, J; Yamaji, T; Morinobu, S; Matsuoka, N; Kato, N

2007-08-10

Post-traumatic stress disorder (PTSD) is a stress-related mental disorder caused by traumatic experience, and presents with characteristic symptoms, such as intrusive memories, a state of hyperarousal, and avoidance, that endure for years. Single-prolonged stress (SPS) is one of the animal models proposed for PTSD. Rats exposed to SPS showed enhanced inhibition of the hypothalamo-pituitary-adrenal (HPA) axis, which has been reliably reproduced in patients with PTSD, and increased expression of glucocorticoid receptor (GR) in the hippocampus. In this study, we characterized further neuroendocrinologic, behavioral and electrophysiological alterations in SPS rats. Plasma corticosterone recovered from an initial increase within a week, and gross histological changes and neuronal cell death were not observed in the hippocampus of the SPS rats. Behavioral analyses revealed that the SPS rats presented enhanced acoustic startle and impaired spatial memory that paralleled the deficits in hippocampal long-term potentiation (LTP) and depression. Contextual fear memory was enhanced in the rats 1 week after SPS exposure, whereas LTP in the amygdala was blunted. Interestingly, blockade of GR activation by administering 17-beta-hydroxy-11-beta-/4-/[methyl]-[1-methylethyl]aminophenyl/-17-alpha-[prop-1-ynyl]estra-4-9-diene-3-one (RU40555), a GR antagonist, prior to SPS exposure prevented potentiation of fear conditioning and impairment of LTP in the CA1 region. Altogether, SPS caused a number of behavioral changes similar to those described in PTSD, which marks SPS as a putative PTSD model. The preventive effects of a GR antagonist suggested that GR activation might play a critical role in producing the altered behavior and neuronal function of SPS rats.

The characterization of obese polycystic ovary syndrome rat model suitable for exercise intervention.

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Chuyan Wu

Full Text Available To develop a new polycystic ovary syndrome (PCOS rat model suitable for exercise intervention.Thirty six rats were randomly divided into three experimental groups: PCOS rats with high-fat diet (PF, n = 24, PCOS rats with ordinary diet (PO, n = 6, and control rats with ordinary diet (CO, n = 6. Two kinds of PCOS rat model were made by adjustment diet structure and testosterone injection for 28 days. After a successful animal model, PF model rats were randomly assigned to three groups: exercise with a continuation of high-fat diet (PF-EF, n = 6, sedentary with a continuation of high-fat diet (PF-SF, n = 6, exercise with an ordinary diet (PF-EO, n = 6. Fasting blood glucose (FBG and insulin (FINS, estrogen (E2, progesterone (P, and testosterone (T in serum were determined by RIA, and ovarian morphology was evaluated by Image-Pro plus 6.0.Body weight, Lee index, FINS increased significantly in PF rat model. Serum levels of E2 and T were significantly higher in PF and PO than in CO. Ovary organ index and ovarian areas were significant lower in PF than in CO. After intervention for 2 weeks, the levels of 1 h postprandial blood glucose (PBG1, 2 h postprandial blood glucose (PBG2, FINS and the serum levels of T decreased significantly in PF-EF rats and PF-EO rats. The ratio of FBG/FINS was significant higher in PF-EO rats than in PF-SF rats. Ovarian morphology showed that the numbers of preantral follicles and atretic follicles decreased significantly, and the numbers of antral follicles and corpora lutea increased significantly in the rats of PF-EF and PF-EO.By combination of high-fat diet and testosterone injection, the obese PCOS rat model is conformable with the lifestyle habits of fatty foods and insufficient exercise, and has metabolic and reproductive characteristics of human PCOS. This model can be applied to study exercise intervention.

Involvement of glucocorticoid-mediated Zn2+ signaling in attenuation of hippocampal CA1 LTP by acute stress.

Science.gov (United States)

Takeda, Atsushi; Suzuki, Miki; Tamano, Haruna; Takada, Shunsuke; Ide, Kazuki; Oku, Naoto

2012-03-01

Glucocorticoid-glutamatergic interactions have been proposed as a potential model to explain stress-mediated impairment of cognition. However, it is unknown whether glucocorticoid-zincergic interactions are involved in this impairment. Histochemically reactive zinc (Zn(2+)) is co-released with glutamate from zincergic neurons. In the present study, involvement of synaptic Zn(2+) in stress-induced attenuation of CA1 LTP was examined in hippocampal slices from young rats after exposure to tail suspension stress for 30s, which significantly increased serum corticosterone. Stress-induced attenuation of CA1 LTP was ameliorated by administration of clioquinol, a membrane permeable zinc chelator, to rats prior to exposure to stress, implying that the reduction of synaptic Zn(2+) by clioquinol participates in this amelioration. To pursue the involvement of corticosterone-mediated Zn(2+) signal in the attenuated CA1 LTP by stress, dynamics of synaptic Zn(2+) was checked in hippocampal slices exposed to corticosterone. Corticosterone increased extracellular Zn(2+) levels measured with ZnAF-2 dose-dependently, as well as the intracellular Ca(2+) levels measured with calcium orange AM, suggesting that corticosterone excites zincergic neurons in the hippocampus and increases Zn(2+) release from the neuron terminals. Intracellular Zn(2+) levels measured with ZnAF-2DA were also increased dose-dependently, but not in the coexistence of CaEDTA, a membrane-impermeable zinc chelator, suggesting that intracellular Zn(2+) levels is increased by the influx of extracellular Zn(2+). Furthermore, corticosterone-induced attenuation of CA1 LTP was abolished in the coexistence of CaEDTA. The present study suggests that corticosterone-mediated increase in postsynaptic Zn(2+) signal in the cytosolic compartment is involved in the attenuation of CA1 LTP after exposure to acute stress. Copyright © 2012 Elsevier Ltd. All rights reserved.

Oxidative stress of crystalline lens in rat menopausal model

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Semra Acer

Full Text Available ABSTRACT Purpose: To evaluate lenticular oxidative stress in rat menopausal models. Methods: Forty Wistar female albino rats were included in this study. A total of thirty rats underwent oophorectomy to generate a menopausal model. Ten rats that did not undergo oophorectomy formed the control group (Group 1. From the rats that underwent oophorectomy, 10 formed the menopause control group (Group 2, 10 were administered a daily injection of methylprednisolone until the end of the study (Group 3, and the remaining 10 rats were administered intraperitoneal streptozocin to induce diabetes mellitus (Group 4. Total oxidant status (TOS, total antioxidant capacity (TAC, and oxidative stress index (OSI measurements of the crystalline lenses were analyzed. Results: The mean OSI was the lowest in group 1 and highest in group 4. Nevertheless, the difference between the groups was not statistically significant in terms of OSI (p >0.05. The mean TOS values were similar between the groups (p >0.05, whereas the mean TAC of group 1 was significantly higher than that of the other groups (p <0.001. Conclusions: Our results indicate that menopause may not promote cataract formation.

Perirhinal cortical inactivation impairs object-in-place memory and disrupts task-dependent firing in hippocampal CA1, but not in CA3.

Science.gov (United States)

Lee, Inah; Park, Seong-Beom

2013-01-01

Objects and their locations can associatively define an event and a conjoint representation of object-place can form an event memory. Remembering how to respond to a certain object in a spatial context is dependent on both hippocampus and perirhinal cortex (PER). However, the relative functional contributions of the two regions are largely unknown in object-place associative memory. We investigated the PER influence on hippocampal firing in a goal-directed object-place memory task by comparing the firing patterns of CA1 and CA3 of the dorsal hippocampus between conditions of PER muscimol inactivation and vehicle control infusions. Rats were required to choose one of the two objects in a specific spatial context (regardless of the object positions in the context), which was shown to be dependent on both hippocampus and PER. Inactivation of PER with muscimol (MUS) severely disrupted performance of well-trained rats, resulting in response bias (i.e., choosing any object on a particular side). MUS did not significantly alter the baseline firing rates of hippocampal neurons. We measured the similarity in firing patterns between two trial conditions in which the same target objects were chosen on opposite sides within the same arm [object-in-place (O-P) strategy] and compared the results with the similarity in firing between two trial conditions in which the rat chose any object encountered on a particular side [response-in-place (R-P) strategy]. We found that the similarity in firing patterns for O-P trials was significantly reduced with MUS compared to control conditions (CTs). Importantly, this was largely because MUS injections affected the O-P firing patterns in CA1 neurons, but not in CA3. The results suggest that PER is critical for goal-directed organization of object-place associative memory in the hippocampus presumably by influencing how object information is associated with spatial information in CA1 according to task demand.

Perirhinal cortical inactivation impairs object-in-place memory and disrupts task-dependent firing in hippocampal CA1, but not in CA3

Directory of Open Access Journals (Sweden)

Inah eLee

2013-08-01

Full Text Available Objects and their locations can associatively define an event and a conjoint representation of object-place can form an event memory. Remembering how to respond to a certain object in a spatial context is dependent on both hippocampus and perirhinal cortex (PER. However, the relative functional contributions of the two regions are largely unknown in object-place associative memory. We investigated the PER influence on hippocampal firing in a goal-directed object-place memory task by comparing the firing patterns of CA1 and CA3 of the dorsal hippocampus between conditions of PER muscimol inactivation and vehicle control infusions. Rats were required to choose one of the two objects in a specific spatial context (regardless of the object positions in the context, which was shown to be dependent on both hippocampus and PER. Inactivation of PER with muscimol (MUS severely disrupted performance of well-trained rats, resulting in response bias (i.e., choosing any object on a particular side. MUS did not significantly alter the baseline firing rates of hippocampal neurons. We measured the similarity in firing patterns between two trial conditions in which the same target objects were chosen on opposite sides within the same arm (object-in-place strategy and compared the results with the similarity in firing between two trial conditions in which the rat chose any object encountered on a particular side (response-in-place strategy. We found that the similarity in firing patterns for object-in-place trials was significantly reduced with MUS compared to control conditions. Importantly, this was largely because MUS injections affected the object-in-place firing patterns in CA1 neurons, but not in CA3. The results suggest that PER is critical for goal-directed organization of object-place associative memory in the hippocampus presumably by influencing how object information is associated with spatial information in CA1 according to task demand.

Effects of chronic stress on the brain – the evidence from morphological examinations of hippocampus in a chronic unpredictable stress (CUS model in rats

Directory of Open Access Journals (Sweden)

Joanna Sekita-Krzak

2016-12-01

    Abstract Background. Chronic stress exposure deteriorates memory and increases the risk of psychiatric disorders, including depression. Objectives. The objective of this study was to perform morphological studies in experimental model of neuropsychiatric disorder and to assess histologically the effect of chronic unpredictable stress procedure (CUS influence on hippocampus. Material and methods. Chronic unpredictable stress procedure (CUS was applied for 8 weeks in rats by the modified method described by Katz et al. Experimental model of neuropsychiatric disorder was used based on morphological studies of hippocampal formation. Results. Stress-induced alterations were observed in the hippocampus. Nerve cell changes included  neuron shrinkage and dendritic remodeling. The most vulnerable hippocampal cells to chronic stress were CA3 and CA4 pyramidal neurons. In dentate gyrus chronic stress led to granule neuron shrinkage and slight exacerbation of apoptosis in the polygonal cell layer. CUS led to statistically significant changes in quantitative characteristics of the CA3 and CA4 neuron size and nuclei diameter. Conclusions. Chronic stress induces degeneration of hippocampal neurons. The observed neuronal changes indicate the damage of the neurons did not involve neither apoptosis nor necrosis Similarity between histological changes obtained in 8-week long CUS procedure applied in our research and morphological changes described in depressed patients confirms the usefulness of the applied stress procedure as the experimental model of depression.   Key words: stress, depression, hippocampus, chronic unpredictable stress procedure (CUS, animal model, morphology.

3H-tetracycline as a proxy for 41Ca for measuring dietary perturbations of bone resorption

International Nuclear Information System (INIS)

Weaver, Connie; Cheong, Jennifer; Jackson, George; Elmore, David; McCabe, George; Martin, Berdine

2007-01-01

Our group is interested in evaluating early effects of dietary interventions on bone loss. Postmenopausal women lose bone following reduction in estrogen which leads to increased risk of fracture. Traditional means of monitoring bone loss and effectiveness of treatments include changes in bone density, which takes 6 months to years to observe effects, and changes in biochemical markers of bone turnover, which are highly variable and lack specificity. Prelabeling bone with 41 Ca and measuring urinary 41 Ca excretion with accelerator mass spectrometry provides a sensitive, specific, and rapid approach to evaluating effectiveness of treatment. To better understand 41 Ca technology as a tool for measuring effective treatments on reducing bone resorption, we perturbed bone resorption by manipulating dietary calcium in rats. We used 3 H-tetracycline ( 3 H-TC) as a proxy for 41 Ca and found that a single dose is feasible to study bone resorption. Suppression of bone resorption, as measured by urinary 3 H-TC, by dietary calcium was observed in rats stabilized after ovariectomy, but not in recently ovariectomized rats

Inhibition of long-term potentiation in the schaffer-CA1 pathway by repetitive high-intensity sound stimulation.

Science.gov (United States)

Cunha, A O S; de Oliveira, J A C; Almeida, S S; Garcia-Cairasco, N; Leão, R M

2015-12-03

High-intensity sound can induce seizures in susceptible animals. After repeated acoustic stimuli changes in behavioural seizure repertoire and epileptic EEG activity might be seen in recruited limbic and forebrain structures, a phenomenon known as audiogenic kindling. It is postulated that audiogenic kindling can produce synaptic plasticity events leading to the spread of epileptogenic activity to the limbic system. In order to test this hypothesis, we investigated if long-term potentiation (LTP) of hippocampal Schaffer-CA1 synapses and spatial navigation memory are altered by a repeated high-intensity sound stimulation (HISS) protocol, consisting of one-minute 120 dB broadband noise applied twice a day for 10 days, in normal Wistar rats and in audiogenic seizure-prone rats (Wistar Audiogenic Rats - WARs). After HISS all WARs exhibited midbrain seizures and 50% of these animals developed limbic recruitment, while only 26% of Wistar rats presented midbrain seizures and none of them had limbic recruitment. In naïve animals, LTP in hippocampal CA1 neurons was induced by 50- or 100-Hz high-frequency stimulation of Schaffer fibres in slices from both Wistar and WAR animals similarly. Surprisingly, HISS suppressed LTP in CA1 neurons in slices from Wistar rats that did not present any seizure, and inhibited LTP in slices from Wistar rats with only midbrain seizures. However HISS had no effect on LTP in CA1 neurons from slices of WARs. Interestingly HISS did not alter spatial navigation and memory in both strains. These findings show that repeated high-intensity sound stimulation prevent LTP of Schaffer-CA1 synapses from Wistar rats, without affecting spatial memory. This effect was not seen in hippocampi from audiogenic seizure-prone WARs. In WARs the link between auditory stimulation and hippocampal LTP seems to be disrupted which could be relevant for the susceptibility to seizures in this strain. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Effect of short-term ornithine alpha-ketoglutarate pretreatment on intestinal ischemia-reperfusion in rats.

Science.gov (United States)

Gonçalves, Eduardo Silvio Gouveia; Rabelo, Camila Menezes; Prado Neto, Alberico Ximenes do; Garcia, José Huygens Parente; Guimarães, Sérgio Botelho; Vasconcelos, Paulo Roberto Leitão de

2011-01-01

To investigate the effects of preventive enteral administration of ornithine alpha-ketoglutarate (OKG) in an ischemia-reperfusion rat model. Sixty rats were randomized into five groups (G1-G5, n = 12). Each group was divided into two subgroups (n = 6) and treated with calcium carbonate (CaCa) or OKG by gavage. Thirty minutes later, the animals were anesthetized with xylazine 15mg + ketamine 1mg ip and subjected to laparotomy. G1-G3 rats served as controls. Rats in groups G4 and G5 were subjected to ischemia for 30 minutes. Ischemia was achieved by clamping the small intestine and its mesentery, delimiting a segment of bowel 5 cm long and 5 cm apart from the ileocecal valve. In addition, G5 rats underwent reperfusion for 30 minutes. Blood samples were collected at the end of the laparotomy (G1), after 30 minutes (G2, G4) and 60 minutes (G3, G5) to determine concentrations of metabolites (pyruvate, lactate), creatine phosphokinase (CPK), thiobarbituric acid reactive substances (TBARS) and glutathione (GSH). There was a significant decrease in tissue pyruvate and lactate and plasma CPK levels in OKG-treated rats at the end of reperfusion period. GSH levels did not change significantly in ischemia and reperfusion groups. However, TBARS levels increased significantly (p<0.05) in tissue samples in OKG-treated rats subjected to ischemia for 30 minutes. Short-term pretreatment with OKG before induction of I/R decreases tissue damage, increases pyruvate utilization for energy production in the Krebs cycle and does not attenuate the oxidative stress in this animal model.

Aspects of inhaled DTPA toxicity in the rat, hamster and beagle dog and treatment effectiveness for excorporation of plutonium from the rat

International Nuclear Information System (INIS)

Smith, V.H.; Ballou, J.E.; Lund, J.E.; Dagle, G.E.; Ragan, H.A.; Busch, R.H.; Hackett, P.L.; Willard, D.W.

1976-01-01

After inhaling 1 to 4 HD (human dose equivalents, i.e. 1g of calcium trisodium N,N-bis(2-bis (carboxymethyl) amino ethyl)glycinate per 70kg of body weight) of Ca-DTPA, rats and hamsters developed a transitory vesicular emphysema. This was not found in animals sacrified later than 3 weeks after the last exposure. Dogs were anesthetized and administered Ca-DTPA aerosols via an intratracheal catheter for 30min/day for 5 days. The average dose/exposure was 4 HD. One week after the last exposure, 3/4 treated dogs and 0/2 dogs exposed to saline aerosols showed enlargement and submucosal lymphoid follicles in the pyloric region of the stomach; this was not present in dogs sacrificed at 4, 8 or 18 weeks post-exposure. Ephitheleal atypia in the alveolar lining was noted in 5/16 dogs inhaling Ca-DTPA and in 1/8 dogs exposed to saline aerosols, and may or may not be treatment-related. In long-term studies, rats were administered a lung burden of about 78 nCi 239 Pu(NO 3 ) 4 by inhalation and 20 days later were given six inhalation treatments of about 1 HD Ca-DTPA. Over their lifetime these animals showed no difference in survival or bone or lung tumour incidence from rats receiving Pu alone. Rats receiving 1.2 μCi 238 Pu(NO 3 ) 4 intramuscularly were treated promptly with 1.2 HD inhaled or intraperitoneally injected Ca-DTPA. The two methods of Ca-DTPA administration gave statistically identical Pu excorporation. Similar treatments initiated 8 months after the Pu injection also showed no effect of administration route. These experiments and implications for the safety and efficacy of inhaled Ca-DTPA as treatment for transuranic incorporations in man are discussed. (author)

Bone metabolism of male rats chronically exposed to cadmium

International Nuclear Information System (INIS)

Brzoska, Malgorzata M.; Moniuszko-Jakoniuk, Janina

2005-01-01

Recently, based on a female rat model of human exposure, we have reported that low-level chronic exposure to cadmium (Cd) has an injurious effect on the skeleton. The purpose of the current study was to investigate whether the exposure may also affect bone metabolism in a male rat model and to estimate the gender-related differences in the bone effect of Cd. Young male Wistar rats received drinking water containing 0, 1, 5, or 50 mg Cd/l for 12 months. The bone effect of Cd was evaluated using bone densitometry and biochemical markers of bone turnover. Renal handling of calcium (Ca) and phosphate, and serum concentrations of vitamin D metabolites, calcitonin, and parathormone were estimated as well. At treatment with 1 mg Cd/l, corresponding to the low environmental exposure in non-Cd-polluted areas, the bone mineral content (BMC) and density (BMD) at the femur and lumbar spine (L1-L5) and the total skeleton BMD did not differ compared to control. However, from the 6th month of the exposure, the Z score BMD indicated osteopenia in some animals and after 12 months the bone resorption very clearly tended to an increase. The rats' exposure corresponding to human moderate (5 mg Cd/l) and especially relatively high (50 mg Cd/l) exposure dose- and duration-dependently disturbed the processes of bone turnover and bone mass accumulation leading to formation of less dense than normal bone tissue. The effects were accompanied by changes in the serum concentration of calciotropic hormones and disorders in Ca and phosphate metabolism. It can be concluded that low environmental exposure to Cd may be only a subtle risk factor for skeletal demineralization in men. The results together with our previous findings based on an analogous model using female rats give clear evidence that males are less vulnerable to the bone effects of Cd compared to females