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Elena Timofeeva - One of the best experts on this subject based on the ideXlab platform.
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sex specific effects of relaxin 3 on food intake and brain expression of corticotropin releasing factor in rats
Endocrinology, 2015Co-Authors: Christophe Lenglos, Juliane Calvez, Elena TimofeevaAbstract:This study compared the effects of relaxin-3 (RLN3) on food intake, plasma corticosterone, and the expression of corticotropin-releasing factor (CRF) in male and female rats. RLN3 was injected into the lateral ventricle at 25, 200, and 800 pmol concentrations. RLN3 at 25 pmol increased food intake (grams) at 30 and 60 minutes after injection in female but not male rats. Female rats also showed higher increase in relative to body weight (BW) food intake (mg/g BW) for all RLN3 concentrations at 30 minutes and for 800 pmol of RLN3 at 60 minutes. Moreover, RLN3 at 800 pmol significantly increased 24-hour BW gain in female but not male rats. At 60 minutes after administration, 800 pmol of RLN3 produced a significant increase in plasma corticosterone and in the expression of CRF and c-fos mRNAs in the parvocellular Paraventricular Hypothalamic Nucleus (PVN) in male but not female rats. The levels of c-fos mRNA in the magnocellular PVN were increased by RLN3 but did not differ between the sexes. Conversely, expr...
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Differential effects of central administration of relaxin-3 on food intake and Hypothalamic neuropeptides in male and female rats
Genes Brain and Behavior, 2015Co-Authors: Juliane Calvez, Christophe Lenglos, Camila De Avila, Geneviève Guèvremont, Elena TimofeevaAbstract:Relaxin-3 (RLN3) is an orexigenic neuropeptide that produces sex-specific effects on food intake by stronger stimulation of feeding in female compared with male rats. This study determined which Hypothalamic nuclei and associated neuropeptides may be involved in the sex-specific orexigenic effects of RLN3. Relaxin-3 (800 pmol) or vehicle was injected into the lateral ventricle of female and male rats. Food and water intake were measured after the first injection, and rats were euthanized after the second injection to determine the mRNA expression of the Hypothalamic neuropeptides. Food but not water intake showed sex-specific effects of RLN3. Stimulation of food intake by RLN3 was significantly higher in female than in male rats. No effect of RLN3 injection was found on c-fos mRNA expression in the arcuate, dorsomedial and ventromedial Hypothalamic nuclei. Increased c-fos mRNA expression was observed in the Paraventricular Hypothalamic Nucleus (PVN) in both sexes and in the lateral Hypothalamic area (LHA) in female rats. Relaxin-3 injections led to a sex-nonspecific increase in the expression of oxytocin mRNA in the magnocellular PVN. Conversely, RLN3-induced expression of anorexigenic neuropeptide arginine vasopressin (AVP) was significantly higher in the parvocellular PVN in male compared with female rats. Finally, RLN3 administration significantly increased the expression of orexin (ORX) mRNA in the LHA in female but not in male rats. Stronger expression of anorexigenic AVP in the PVN in male rats and increased expression of ORX in the LHA in female rats may contribute to stronger orexigenic effects of RLN3 in female rats compared with male rats.
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Sex differences in the effects of chronic stress and food restriction on body weight gain and brain expression of CRF and relaxin-3 in rats.
Genes brain and behavior, 2013Co-Authors: Christophe Lenglos, Geneviève Guèvremont, Arojit Mitra, Elena TimofeevaAbstract:This study investigated sex-specific effects of repeated stress and food restriction on food intake, body weight, corticosterone plasma levels and expression of corticotropin-releasing factor (CRF) in the hypothalamus and relaxin-3 in the Nucleus incertus (NI). The CRF and relaxin-3 expression is affected by stress, and these neuropeptides produce opposite effects on feeding (anorexigenic and orexigenic, respectively), but sex-specific regulation of CRF and relaxin-3 by chronic stress is not fully understood. Male and female rats were fed ad libitum chow (AC) or ad libitum chow and intermittent palatable liquid Ensure without food restriction (ACE), or combined with repeated food restriction (60% chow, 2 days per week; RCE). Half of the rats were submitted to 1-h restraint stress once a week. In total, seven weekly cycles were applied. The body weight of the RCE stressed male rats significantly decreased, whereas the body weight of the RCE stressed female rats significantly increased compared with the respective control groups. The stressed female RCE rats considerably overate chow during recovery from stress and food restriction. The RCE female rats showed elevated plasma corticosterone levels and low expression of CRF mRNA in the Paraventricular Hypothalamic Nucleus but not in the medial preoptic area. The NI expression of relaxin-3 mRNA was significantly higher in the stressed RCE female rats compared with other groups. An increase in the expression of orexigenic relaxin-3 and misbalanced Hypothalamic-pituitary-adrenal axis activity may contribute to the overeating and increased body weight seen in chronically stressed and repeatedly food-restricted female rats.
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corticotropin releasing factor and its receptors in the brain of rats with insulin and corticosterone deficits
Journal of Molecular Endocrinology, 2006Co-Authors: Qingling Huang, Elena Timofeeva, Denis RichardAbstract:The expression of genes encoding corticotropin-releasing factor (CRF) and its receptor type-1 (CRF1R) and type-2alpha (CRF2R) has been studied in the brain of rats with streptozotocin (STZ)-induced diabetes and adrenalectomy (ADX). Diabetic rats had a lower body weight compared to control rats. Food and water intake were increased in diabetic rats and decreased in ADX animals. The plasma corticosterone levels measured at the nadir of the circadian rhythm were significantly higher in diabetic rats compared to non-diabetic animals. STZ-diabetic rats demonstrated an induction of expression of CRF mRNA in the magnocellular part of the Paraventricular Hypothalamic Nucleus (PVN) and in the supraoptic Nucleus (SON), whereas the CRF transcript in the parvocellular PVN was significantly lower in rats with insulin deficiency. ADX strongly triggered the expression of CRF mRNA in the parvocellular neurons of the PVN in both non-diabetic and diabetic rats, and it decreased magnocellular CRF mRNA in diabetic animals. The expression of the CRF1R in the parvocellular and magnocellular PVN and in the SON was induced by diabetes and decreased after ADX. The levels of the CRF2R mRNA in the ventromedial Hypothalamic Nucleus (VMH) were significantly lower in diabetic rats without any noticeable effects of ADX. The present results suggest opposite effects of insulin and corticosterone deficiency on the hypophysiotropic CRF and the CRF1R mRNA contents, whereas the expression of CRF2R was mostly related to insulin, but not to the corticosterone status.
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contribution of the vagus nerve and lamina terminalis to brain activation induced by refeeding
European Journal of Neuroscience, 2005Co-Authors: Elena Timofeeva, Elena Dana Baraboi, Denis RichardAbstract:Following refeeding, c-fos expression is induced in a particular set of brain regions that include the Nucleus of the solitary tract (NTS), parabrachial Nucleus (PB), central amygdala (CeA), Paraventricular Hypothalamic Nucleus (PVH), supraoptic Nucleus (SON) and the circumventricular organs. Within the PVH, the expression is particularly intense in the magnocellular division of the Nucleus and it is as yet not clear how this activation occurs. The respective contribution of the vagus afferents and lamina terminalis, which conveys signals entering the brain through the forebrain circumventricular organs, has been investigated in rats subjected to a unilateral cervical vagotomy (UCV) or a unilateral lesion of the fibres running within the lamina terminalis (ULT) and projecting to the neuroendocrine hypothalamus. UCV significantly decreased postprandial c-fos expression in the NTS, PB, CeA and parvocellular division of the PVH. In contrast, ULT impaired postprandial activation of the magnocellular neurons in the PVH and SON. The present study also characterized the types of neurons activated in the PVH and SON during refeeding. In the magnocellular regions, arginine-vasopressin (AVP) neurons were activated upon refeeding whereas there was no apparent induction of Fos expression in oxytocin cells. In the parvocellular PVH, postprandial Fos was induced only in 30% of the corticotrophin-releasing factor (CRF) and AVP neurons. The results of the present study suggest that the postprandial activation of the brain requires the integrity of both the vagal- and lamina terminalis-associated pathways.
Hitoshi Kawano - One of the best experts on this subject based on the ideXlab platform.
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Synaptic contact between median preoptic neurons and subfornical organ neurons projecting to the Paraventricular Hypothalamic Nucleus
Experimental Brain Research, 2017Co-Authors: Hitoshi KawanoAbstract:It is known that the median preoptic Nucleus (POMe) sends dense projections to the subfornical organ (SFO). However, the functional significance of these projections have not been well discussed. In this electron microscopic study, we investigated the presence of synapses between POMe-derived axon terminals and SFO neurons that project to the Paraventricular Hypothalamic Nucleus (PVN). After injection of a retrograde tracer, wheat germ agglutinin-conjugated horseradish peroxidase–colloidal gold complex, into the PVN, many labeled neurons were found in the SFO. In contrast, after injection of an anterograde tracer, biotinylated dextran amine, in the POMe, abundant labeled axon varicosities were observed in the SFO. Using electron microscopy, synapses were identified between retrogradely labeled dendrites and cell bodies, and anterogradely labeled axon terminals, indicating that POMe neurons innervate SFO neurons projecting to the PVN. The possibility that POMe neurons play multiple roles in the neuronal circuit responsible for vasopressin release and/or cardiovascular regulation is also discussed.
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region specific projections from the subfornical organ to the Paraventricular Hypothalamic Nucleus in the rat
Neuroscience, 2010Co-Authors: Hitoshi Kawano, Sadahiko MasukoAbstract:Neurons in the subfornical organ (SFO) project to the Paraventricular Hypothalamic Nucleus (PVN) and there, in response to osmolar and blood pressure changes, regulate vasopressin neurons in the magnocellular part (mPVN) or neurons in the parvocellular part (pPVN) projecting to the cardiovascular center. The SFO is functionally classified in two parts, the dorsolateral peripheral (pSFO) and ventromedial core parts (cSFO). We investigated the possibility that neurons in each part of the SFO project region-specifically to each part of the PVN, using anterograde and retrograde tracing methods. Following injection of an anterograde tracer, biotinylated dextran amine (BDX) in the SFO, the respective numbers of BDX-uptake neurons in the pSFO and cSFO were counted and the ratio of the former to the latter was obtained. In addition, the respective areas occupied by BDX-labeled axons per unit area of the mPVN and pPVN were measured and the ratio of the former to the latter was obtained. Similarly, following injection of the retrograde tracer in the PVN, the respective areas occupied by tracer per unit area of the mPVN and pPVN were measured and the ratio of the former to the latter was obtained. The respective numbers of retrogradely labeled neurons in the pSFO and cSFO were also counted and the ratio of the former to the latter was obtained. It became clear by statistical analyses that there are strong positive correlations between the ratio of BDX-uptake neuron number in the SFO and the ratio of BDX-axon area in the PVN in anterograde experiment (correlation coefficient: 0.787) and between the ratio of retrograde neuron number in the SFO and the ratio of tracer area in the PVN in retrograde experiment (correlation coefficient: 0.929). The result suggests that the SFO projects region-specifically to the PVN, the pSFO to the mPVN and the cSFO to the pPVN.
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collateral projections from the subfornical organ to the median preoptic Nucleus and Paraventricular Hypothalamic Nucleus in the rat
Brain Research, 2008Co-Authors: Pingguo Duan, Hitoshi Kawano, Sadahiko MasukoAbstract:It is morphologically demonstrated that the subfornical organ (SFO) projects to the Paraventricular Hypothalamic Nucleus (PVN) and also projects to the Nucleus preopticus medianus (POMe), a relay Nucleus of indirect projections from the SFO to PVN. However, it remains unknown, whether or not SFO neurons project collaterally to the POMe and PVN. To confirm this, a double retrograde labeling method was performed on rats using two fluorescent tracers. One tracer (red-colored FluoSpheres: FSR) was injected into the POMe and the other (Fast Blue: FB) was injected into the unilateral PVN at the same time. As a result, many retrogradely labeled neurons were found in the entire SFO. Of these, some neurons showed both FSR and FB fluorescence. Double-labeled neurons were found in about 8.7% of FSR-labeled neurons and 15.5% of FB-labeled neurons. The existence of double-labeled neurons indicates that single neurons in the SFO project simultaneously to the POMe and PVN via collateral axon branches. The data suggest that there are complicated neuronal pathways originating from the SFO in regulating cardiovascular and body fluid homeostasis.
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Synaptic contacts between nerve terminals originating from the ventrolateral medullary catecholaminergic area and median preoptic neurons projecting to the Paraventricular Hypothalamic Nucleus.
Brain research, 1999Co-Authors: Hitoshi Kawano, S MasukoAbstract:A significant role of catecholaminergic projection to the median preoptic Nucleus (POMe) which activates vasopressin-producing cells of the Paraventricular Hypothalamic Nucleus (PVN) has been suggested. We investigated the existence of the synaptic contacts between catecholaminergic fibers from the ventrolateral medulla and the POMe neurons projecting to the PVN. Rats received a retrograde tracer in the PVN and subsequently an anterograde tracer into the catecholaminergic area of the ventrolateral medulla at the level of the area postrema. In the POMe, anterogradely labeled nerve terminals were found to make axo-somatic and axo-dendritic synaptic contacts onto retrogradely labeled neurons. Additional studies in which a retrograde tracer was injected into the POMe revealed that almost all retrogradely labeled neurons in the ventrolateral medulla at the level of the area postrema were immunoreactive to tyrosine hydroxylase, suggesting that projection to the POMe from the ventrolateral medulla is largely limited to catecholamine neurons. These results provide, for the first time, direct evidence that catecholaminergic inputs from the ventrolateral medulla affect POMe neurons projecting to the PVN by way of direct synaptic contact.
Wendy Saltzman - One of the best experts on this subject based on the ideXlab platform.
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individual variation in paternal responses of virgin male california mice peromyscus californicus behavioral and physiological correlates
Physiological and Biochemical Zoology, 2012Co-Authors: Trynke R. De Jong, Breanna N. Harris, Juan Pablo Perearodriguez, Aniko Korosi, Wendy SaltzmanAbstract:AbstractCalifornia mice Peromyscus californicus are a rodent species in which fathers provide extensive paternal care; however, behavioral responses of virgin males toward conspecific neonates vary from paternal behavior to tolerance to infanticide. Indirect evidence suggests that paternal responses might be influenced by social status potentially through increased stress and anxiety in subordinate males. To test this hypothesis, we housed 12 virgin male California mice in same-sex dyads on weaning and assessed their within-dyad subordinate or dominant status using food-competition and urine-marking tests. In addition, behavioral responses to an unrelated pup, expression of vasopressin (AVP) and corticotropin-releasing hormone (CRH) mRNA in the Paraventricular Hypothalamic Nucleus (PVN), basal plasma levels of testosterone and corticosterone, and body mass were measured. Food-competition and urine-marking tests did not reveal strong or stable dominance-subordination relationships in male-male dyads. Laten...
Trynke R. De Jong - One of the best experts on this subject based on the ideXlab platform.
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individual variation in paternal responses of virgin male california mice peromyscus californicus behavioral and physiological correlates
Physiological and Biochemical Zoology, 2012Co-Authors: Trynke R. De Jong, Breanna N. Harris, Juan Pablo Perearodriguez, Aniko Korosi, Wendy SaltzmanAbstract:AbstractCalifornia mice Peromyscus californicus are a rodent species in which fathers provide extensive paternal care; however, behavioral responses of virgin males toward conspecific neonates vary from paternal behavior to tolerance to infanticide. Indirect evidence suggests that paternal responses might be influenced by social status potentially through increased stress and anxiety in subordinate males. To test this hypothesis, we housed 12 virgin male California mice in same-sex dyads on weaning and assessed their within-dyad subordinate or dominant status using food-competition and urine-marking tests. In addition, behavioral responses to an unrelated pup, expression of vasopressin (AVP) and corticotropin-releasing hormone (CRH) mRNA in the Paraventricular Hypothalamic Nucleus (PVN), basal plasma levels of testosterone and corticosterone, and body mass were measured. Food-competition and urine-marking tests did not reveal strong or stable dominance-subordination relationships in male-male dyads. Laten...
Denis Richard - One of the best experts on this subject based on the ideXlab platform.
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corticotropin releasing factor and its receptors in the brain of rats with insulin and corticosterone deficits
Journal of Molecular Endocrinology, 2006Co-Authors: Qingling Huang, Elena Timofeeva, Denis RichardAbstract:The expression of genes encoding corticotropin-releasing factor (CRF) and its receptor type-1 (CRF1R) and type-2alpha (CRF2R) has been studied in the brain of rats with streptozotocin (STZ)-induced diabetes and adrenalectomy (ADX). Diabetic rats had a lower body weight compared to control rats. Food and water intake were increased in diabetic rats and decreased in ADX animals. The plasma corticosterone levels measured at the nadir of the circadian rhythm were significantly higher in diabetic rats compared to non-diabetic animals. STZ-diabetic rats demonstrated an induction of expression of CRF mRNA in the magnocellular part of the Paraventricular Hypothalamic Nucleus (PVN) and in the supraoptic Nucleus (SON), whereas the CRF transcript in the parvocellular PVN was significantly lower in rats with insulin deficiency. ADX strongly triggered the expression of CRF mRNA in the parvocellular neurons of the PVN in both non-diabetic and diabetic rats, and it decreased magnocellular CRF mRNA in diabetic animals. The expression of the CRF1R in the parvocellular and magnocellular PVN and in the SON was induced by diabetes and decreased after ADX. The levels of the CRF2R mRNA in the ventromedial Hypothalamic Nucleus (VMH) were significantly lower in diabetic rats without any noticeable effects of ADX. The present results suggest opposite effects of insulin and corticosterone deficiency on the hypophysiotropic CRF and the CRF1R mRNA contents, whereas the expression of CRF2R was mostly related to insulin, but not to the corticosterone status.
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contribution of the vagus nerve and lamina terminalis to brain activation induced by refeeding
European Journal of Neuroscience, 2005Co-Authors: Elena Timofeeva, Elena Dana Baraboi, Denis RichardAbstract:Following refeeding, c-fos expression is induced in a particular set of brain regions that include the Nucleus of the solitary tract (NTS), parabrachial Nucleus (PB), central amygdala (CeA), Paraventricular Hypothalamic Nucleus (PVH), supraoptic Nucleus (SON) and the circumventricular organs. Within the PVH, the expression is particularly intense in the magnocellular division of the Nucleus and it is as yet not clear how this activation occurs. The respective contribution of the vagus afferents and lamina terminalis, which conveys signals entering the brain through the forebrain circumventricular organs, has been investigated in rats subjected to a unilateral cervical vagotomy (UCV) or a unilateral lesion of the fibres running within the lamina terminalis (ULT) and projecting to the neuroendocrine hypothalamus. UCV significantly decreased postprandial c-fos expression in the NTS, PB, CeA and parvocellular division of the PVH. In contrast, ULT impaired postprandial activation of the magnocellular neurons in the PVH and SON. The present study also characterized the types of neurons activated in the PVH and SON during refeeding. In the magnocellular regions, arginine-vasopressin (AVP) neurons were activated upon refeeding whereas there was no apparent induction of Fos expression in oxytocin cells. In the parvocellular PVH, postprandial Fos was induced only in 30% of the corticotrophin-releasing factor (CRF) and AVP neurons. The results of the present study suggest that the postprandial activation of the brain requires the integrity of both the vagal- and lamina terminalis-associated pathways.
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effects of leptin on corticotropin releasing factor crf synthesis and crf neuron activation in the Paraventricular Hypothalamic Nucleus of obese ob ob mice
Endocrinology, 1998Co-Authors: Qingling Huang, Robert Rivest, Denis RichardAbstract:The effects of leptin on the levels of CRF messenger RNA (mRNA) in the Paraventricular Hypothalamic Nucleus (PVN), on the activation of the PVN CRF cells, and on the plasma levels of corticosterone were investigated in lean (+/?) and obese (ob/ob) C57BL/6J male mice. Murine leptin was sc infused using osmotic minipumps. The treatment period extended to 7 days, and the daily dose of leptin delivered was 100 μg/kg. The mice were killed either in a fed state or following 24 h of total food deprivation. The starvation paradigm was employed to enhance the activity of the Hypothalamic-pituitary-adrenal axis in obese mice. In situ hybridization histochemistry was performed to determine the PVN levels of CRF mRNA and the arcuate Nucleus levels of neuropeptide Y mRNA. The activity of the PVN CRF cells was estimated from the number of PVN cells colocalizing CRF mRNA and the protein Fos. Leptin led to a reduction in body weight gain and fat deposition. These effects were seen in both +/? and ob/ob mice and were obse...
