bluuebunny/crossref_metadata_2025_split huggingface dataset:
P‐chlorophenylallanine Facilitates Copulatory Behavior in Septal Lesioned but not in Preoptic Lesioned Male Rats
Authors: Kondo Yasuhiko , Yamanouchi Korehito , Arai Yasumasa 
Published: September 2006

AbstractEffects of p‐chlorophenylalanine (pCPA), synthesis‐inhibitor of serotonin, on copulatory behavior were examined in testosterone (T) treated castrated male rats with lesions in the lateral septum (LSL) or in the medial preoptic area (MPOL). Three weeks after the operation, all animals were chronically treated with T using silastic capsules. Behavioral tests were carried out at 10 and 20 days after the implantation of T. In half of the males in each group, 100 mg/Kg pCPA was injected daily for 4 days before each test. The other half of the group was injected with saline instead of pCPA. In saline‐treated groups, the males with LSL or MPOL showed extremely lower frequencies of mount and intromission than control males without brain surgery. PCPA‐treated control males showed higher copulatory activities than saline‐treated control males. In contrast, even after the treatment with pCPA, severe impairment of sexual behavior was observed in males with MPOL. On the other hand, pCPA‐treated LSL males displayed copulatory behavior more frequently than saline‐treated LSL males. These results agreed with previous reports that both the medial preoptic area and the lateral septum play an excitatory role in regulating male sexual behavior. Conversely, the serotonergic neuronal system exerts an inhibitory influence for male sexual behavior. Furthermore, these results suggest that the inhibitory function of serotonergic neurons govern dependently on the function of the medial preoptic area, but independently on the function of the lateral septum.
Secretogranin II: Regulation of Synthesis and Post‐Translational Proteolysis in Bovine Adrenal Chromaffin Cells
Authors: Soszynski Darek , Metz‐Boutigue Marie‐Hélène , Aunis Dominique , Bader Marie‐France 
Published: September 2006

AbstractSecretogranin M (Sgll), also called chromogranin C, is an acidic tyrosine‐sulfated secretory protein found in secretory granules in a wide variety of endocrine cells and neurones. Although less abundant than chromogranin A (CGA) and chromogranin B (CGB), Sgll is found in adrenal medullary chromaffin granules. In the present study we investigated the regulation of Sgll biosynthesis in bovine chromaffin cells maintained in primary culture. Cellular proteins were labelled with [35S]methionine and the heat stable chromogranin enriched fraction was isolated. Following electrophoretic separation, the 86 kDa Sgll band was identified by sequence analysis using the Edman degradation procedure. The radioactivity incorporated in the 86 kDa Sgll band was used as an index of the Sgll synthesis rate. We found that stimulation of chromaffin cells with nicotine and histamine and to a smaller extent with angiotensin II and bradykinin significantly enhanced the rate of Sgll synthesis. In contrast direct depolarization with K+ had no effect on Sgll synthesis suggesting that the raise of cytosolic calcium evoked by high K+ may not be sufficient to induce modifications in Sgll synthesis. The possible second messenger pathways involved in the control of Sgll biosynthesis were investigated by using protein kinase C and adenylate cyclase activators. We observed that 12‐O‐tetradecanoylphorbol 13‐acetate (TPA) and forskolin increased the basal rate of Sgll synthesis. Incubation with both TPA and forskolin was required to obtain an effect comparable to that produced by nicotine or histamine suggesting that these secretagogues recruit both protein kinase C‐ and cyclic AMP‐dependent mechanisms to stimulate Sgll synthesis. Our results indicate that within chromaffin granules, the rates of CGA, CGB and Sgll synthesis are independently regulated and suggest a close relationship between the cell secretory activity and the biosynthesis of Sgll.The biological role of Sgll is unknown but it has been suggested that the protein may function as a precursor of potentially bioactive peptides. Here we identified a Sgll derived peptide corresponding to the C‐terminal residues 582–586 in the soluble core of purified chromaffin granules. This peptide was released together with catecholamines upon stimulation of cultured chromaffin cells indicating that the peptide was present within the storage complex of chromaffin granules and was not the result of some artefactual proteolytic degradation of Sgll during the course of granule purification. We propose that this peptide is a specific product of the post‐translational processing of Sgll. By analogy with peptides derived from CGA and CGB, it may possess some specific biological activity that remains to be identified.
Regulation of Cholecystokinin Receptors in the Hypothalamus of the Rat: Reciprocal Changes in Magnocellular Nuclei Induced by Food Deprivation and Dehydration
Authors: O'Shea Ross D. , Gundlach Andrew L. 
Published: September 2006

AbstractCholecystokinin (CCK) has been suggested to mediate satiety in a number of non‐primate species via its peripheral actions as well as a possible central mechanism involving magnocellular and parvocellular oxytocin release. Quantitative in vitro autoradiography employing [125l]‐Bolton‐Hunter labelled CCK‐8S ([125I]‐CCK‐8S) was used to examine the distribution and density of CCK receptors in sections of brain from normal rats and rats deprived of food, water or both food and water for 4 days. In food‐deprived rats, specific [125I]‐CCK‐8S binding was reduced by 64 ± 5% in the hypothalamic supraoptic nucleus (SON) and by 44±13% in the paraventricular nucleus of the hypothalamus (PVN). In contrast, water deprivation increased binding of [125I]‐CCK‐8S by 128±15% in the SON and by 196 ± 24% in the PVN, while combined food and water deprivation produced smaller increases in both nuclei (30 ± 5% and 98 ± 26% in SON and PVN respectively). Changes in receptor density in the PVN appeared to be most prominent in the magnocellular (especially oxytocin‐rich) subdivisions. None of the treatments employed produced changes in [125I]‐CCK‐8S binding in the ventromedial hypothalamic nucleus or the reticular thalamic nucleus. Both CCK‐A and CCK‐B receptor subtypes were visualized in the nucleus of the solitary tract and the area postrema of normal rats, but levels of binding to both of these subtypes were unaffected by the experimental treatments. These selective alterations demonstrate the plasticity of CCK receptors in the SON and PVN, and are probably associated with changes in the level of neurochemical activity of magnocellular oxytocinergic neurones in these areas. These results, together with reports of changes in the level of CCK synthesis in cells of the SON and PVN after hyperosmotic stimuli, suggest that CCK may act in an autocrine fashion on these neurones and that both CCK receptors and peptide levels are altered in the same direction following cellular activation or inhibition.
Changes in Pro‐Opiomelanocortin and Pre‐proenkephalin mRNA Levels in the Ovine Brain during Pregnancy, Parturition and Lactation and in Response to Oestrogen and Progesterone
Authors: Broad K. D. , Kendrick K. M. , Sirinathsinghji D. J. S. , Keverne E. B. 
Published: September 2006

AbstractIn the female sheep opioids act centrally to influence both oxytocin release and maternal behaviour. We have used in situ hybridization histochemistry to investigate the changes in mRNA expression of the two opioid precursor genes, proopiomelanocortin (POMC) and pre‐proenkephalin (PPE), in discrete hypothalamic nuclei as a function of pregnancy, parturition and lactation and following treatment with oestrogen and progesterone. Quantitative in situ hybridization histochemistry demonstrated that POMC mRNA expression in the arcuate nucleus (ARC) decreased at parturition and increased during lactation compared to late pregnant and ovariectomized animals. Oestradiol and progesterone treatments increased POMC mRNA expression compared to ovariectomized controls. Pre‐proenkephalin mRNA expression was quantified in three discrete hypothalamic nuclei, the ventromedial nucleus (VMN), the paraventricular nucleus (PVN) and the suprachiasmatic nucleus (SCN). In the VMN, PPE mRNA expression increased during lactation compared to late pregnancy and parturition. Expression levels during late pregnancy and parturition were decreased compared to ovariectomized animals. Oestradiol increased, and progesterone decreased, PPE mRNA levels compared to ovariectomized controls. Combined progesterone followed by oestrogen treatment produced significant increases in PPE mRNA expression. In the PVN, PPE expression increased at parturition compared to late pregnant, lactating and ovariectomized animals. Expression levels in late pregnant animals were decreased compared to lactating or ovariectomized ones. However, sex steroid treatment produced no changes in PPE expression in the PVN. No changes were observed in PPE mRNA expression in the SCN in response to any of the experimental conditions. This data shows that both POMC and PPE mRNA levels are altered in the sheep brain during pregnancy, parturition and lactation and in response to sex steroids, although the direction of the changes is not always the same and in the case of PPE only the VMN and PVN are affected. Levels of gene expression found following exogenous steroid treatment do not precisely mirror those found during pregnancy, parturition and lactation and this suggests that factors other than changing sex steroids levels are involved. In the context of maternal behaviour it is interesting to note that PPE mRNA expression increases at parturition in the PVN when oxytocin mRNA expression levels are also increased.
Rapid Changes in Somatostatin and TRH mRNA in Whole Rat Hypothalamus in Response to Acute Cold Exposure
Authors: Rage Florence , Lazaro Jean‐Bernard , Benyassi Ahmed , Arancibia Sandor , Tapia‐Arancibia Lucia 
Published: September 2006

AbstractAcute cold stimulus induces activation of the thyreotropic axis characterized by a rapid increase in plasma thyrotropin (TSH). Since pituitary TSH release is mainly regulated by two hypothalamic hormones: thyrotropin‐releasing hormone (TRH) and somatostatin, the aim of this study was to analyse whether changes in the steady state mRNA levels and peptide content of these neurohormones occur under acute cold stimulation in rats. Northern blot analysis of hypothalamic somatostatin mRNA levels after 15, 30, 60 or 180 min of cold exposure revealed a 2.0‐fold increase after 15 min at 4°C. This augmentation was followed by a return to control values at 30 min. However, the hypothalamic content of somatostatin was not significantly modified at any cold exposure time. TRH mRNA showed a similar pattern to somatostatin, with a 2.5‐fold increase after 15 min at 4°C. In contrast, hypothalamic TRH content was significantly decreased after 15 min cold exposure, returning to control values at 30 min. The increase in mRNA levels was specific for the two hypothalamic hormones, since there was no concomitant variation in GAPDH mRNA used as negative control. These results suggest that the organism is quickly aroused by cold stimulus, triggering rapid activation in transcription of the two neurohormones involved in the regulation of the thyreotrope axis. Since the peptide contents did not show the same pattern, a quantitative change in transcription or in mRNA stability does not appear to be a prerequisite for increased peptide expression, suggesting that somatostatin and TRH gene expressions could be regulated at translational or post‐translational steps.
Effect of Late Hypothalamo‐Pituitary Disconnection on the Development of the HPA Axis in the Ovine Fetus and the Initiation of Parturition
Authors: Deayton Jan M. , Young I. Ross , Hollingworth Samantha A. , White Anne , Crosby Steve R. , Thorburn Geoffrey D. 
Published: September 2006

AbstractThe studies of Liggins et al. (1) in which fetuses stalk‐sectioned from day 116 onwards delivered at or near term, suggested that a connection between the fetal hypothalamus and pituitary is not essential for parturition to occur. The objective of this study was to repeat these experiments on the effects of pituitary stalk sections at different gestational ages and include information on the plasma concentrations of key fetal hormones. We have used the more sophisticated technique of hypothalamo‐pituitary disconnection (HPD) at either of two gestational age ranges (123–127 days or 133–135 days). Completeness of the procedure was assessed by demonstrating an attenuated prolactin response to chlorpromazine challenge. Following HPD, gestation was prolonged for at least eight days beyond term (146.2 ± 1.5 days) in 9 of the 10 fetuses operated. Fetal plasma ACTH1–39 concentrations were not different between the HPD and control fetuses, increasing in all groups with increasing gestation. Fetal plasma cortisol concentrations increased (P<0.01) in control fetuses over gestation. Cortisol concentrations did not change significantly in the day 125 HPD group following HPD but increased in the day 135 HPD group (P<0.05) with advancing gestation. These latter concentrations, however were markedly less (P< 0.001) than those for control fetuses prior to parturition. Fetal and maternal plasma PGE2 concentrations increased (P<0.01) in the control group over gestation but did not change following HPD. Maternal plasma progesterone concentrations decreased (P<0.05) after day 143 in the control group but did not change in the HPD group. There was no change in maternal plasma concentrations of prostaglandin FM in the HPD group. These findings demonstrate that hypothalamic connection to the pituitary needs to be maintained until at least day 135 of gestation for the initiation of parturition at term.
Chronic Administration of Glucocorticoids Directly Upregulates Prepro‐Neuropeptide Y and Y1‐Receptor mRNA Levels in the Arcuate Nucleus of the Rat
Authors: Larsen Philip J. , Jessop David S. , Chowdrey Hardial S. , Lightman Stafford L. , Mikkelsen Jens D. 
Published: September 2006

AbstractThe complete sequence of the cDNA encoding the neuropeptide Y (NPY) Y1‐receptor has recently been deduced from a rat brain library, and the presence of messenger ribonucleic acid (mRNA) encoding Y1‐receptor protein has been demonstrated within the brain. Using quantitative in situ hybridization histochemistry, the content and distribution of Y1receptor and preproNPY mRNAs have been investigated in the hypothalamic arcuate nucleus of adrenalectomized rats receiving glucocorticoid replacement therapy for 12 days by means of either high doses of dexamethasone in their drinking water or by subcutaneous corticosterone pellets. Basal metabolic parameters such as weight gain or loss, blood glucose and plasma insulin were monitored: Dexamethasone treatment induced weight loss and a state of hyperinsulinemia with normoglycemia, while corticosterone treated animals displayed metabolic parameters identical to sham ADX animals. Within the arcuate nucleus of glucocorticoid treated animals, levels of Y1receptor and preproNPY mRNAs were increased. In contrast, adrenalectomy itself had no effect upon Y1‐receptor mRNA levels or preproNPY mRNA levels in the arcuate nucleus. These studies demonstrate that glucocorticoids exert a stimulatory action on levels of Y1‐receptor mRNA and preproNPY mRNA levels in the hypothalamic arcuate nucleus. This is the first evidence to suggest that the expression of a neuropeptide‐receptor gene in the central nervous system may be directly sensitive to peripheral hormonal signals.
Effects in vitro of New Growth Hormone Releasing Peptide (GHRP‐1) on Growth Hormone Secretion from Ovine Pituitary Cells in Primary Culture
Authors: Wu Danxing , Chen Chen , Zhang Jin , Katoh Kazuo , Clarke Lain 
Published: September 2006

AbstractContinuous perifusion of pituitary cells was used to study the effects of a newly synthesized GHRP (GHRP‐1 or KP 101) on growth hormone (GH) secretion from ovine pituitary cells and these have been compared to effects of growth hormone‐releasing factor (GRF) and the original growth hormone‐releasing peptide (GHRP‐6). GH was continuously released at a constant rate during perifusion and secretion was increased by KP 101, GHRP‐6 and GRF in a dose‐dependent manner. The half‐maximal effective dose of KP 101 and GHRP‐6 was 10−7 M, an order of magnitude higher than that for GRF. The maximal effects of KP 101 and GHRP‐6 were similar but significantly less than the maximal effect of GRF. Blockade of calcium channels with Cd2+ (2 mM) totally and reversibly abolished the releasing effects of all three peptides. Like GHRP‐6, the GH release induced by KP 101 was not affected by a GRF antagonist ([Ac‐Tyr1, D‐Arg2]‐GRF 1–29, 1 μM) which significantly reduced the effect of GRF on GH release. For each peptide, the response to a second application (1 h after the first application) was lower than the first response. When GRF (or KP 101, GHRP‐6) was applied first and then KP 101 or GHRP‐6 (or GRF) given 1 h later, the second response was not attenuated. Only a small additive effect on the release of GH by GRF was obtained by the co‐administration of either KP 101 or GHRP‐6. This result was achieved with maximal doses of the peptides, but not with half‐maximal doses. These data indicate that KP 101 has similar potency and GH releasing properties to GHRP‐6 but both are less potent than GRF. There is no synergistic effect of the peptides with GRF and only a small additive effect of KP 101 or GHRP‐6 on GRF‐stimulated GH release from ovine pituitary cells in vitro. KP 101 stimulates GH release by a mechanism that involves a common step employed also by GRF and GHRP‐6, an increase in calcium influx. In addition, our data strongly suggest that KP 101 like GHRP‐6 do not act through the GRF receptor and that there is no cross‐desensitization the GRF elicited response.
Prolactin Receptor mRNA Localization in the Hypothalamus by in situ Hybridization
Authors: Chiu Sufen , Wise Phyllis M. 
Published: September 2006

AbstractProlactin receptors may mediate the action of prolactin in the brain to influence behavior and neuroendocrine secretions. We recently demonstrated prolactin receptor gene expression in the anterior and medial basal hypothalamus and not in the cortex by the reverse transcription‐polymerase chain reaction. In this paper, we localize the prolactin receptor gene expression to individual cells with in situ hybridization. Several steps in the in situ hybridization method were modified to increase sensitivity by using (i) probes complementary to the coding sequence of the extracellular binding domain common to both long and short prolactin receptor, (ii) more stringent hybridization and wash conditions to reduce background and (iii) higher specific activity, more complex and saturating amounts of probe. We detected prolactin receptor gene expression in cells of the periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, rostral arcuate nucleus and choroid plexus. Cortical brain tissue, which has been demonstrated previously by reverse‐transcription polymerase chain reaction to be lacking in prolactin receptor mRNA, did not have any detectable signal for the receptor mRNA and was used as an indication of background levels of signal. The mean area of silver grains over labeled cells in periventricular area of the preoptic nucleus, medial preoptic nucleus, supraoptic nucleus, arcuate nucleus, lateral ventromedial nucleus was at least 10 times greater than the background in the cortex of the same brain section.
Proopiomelanocortin Gene Expression During Pig Pituitary and Brain Development
Authors: Ma E. , Milewski N. , Grossmann R. , IveII R. , Kato Y. , Ellendorff F. 
Published: September 2006

AbstractThe expression of proopiomelanocortin (POMC) mRNA, which plays an important role in neural, endocrine, neuroendocrine and immune systems, was studied by in situ hybridization during the development of pituitary in the domestic pig. The POMC gene was activated as early as fetal day 30 (E30). The signal for POMC mRNA in the anterior lobe progressively increased from E30 to E80 and then remained at relatively constant level. In contrast, POMC transcripts in the intermediate lobe first appeared at E40 and steadily increased during development. POMC transcripts in the brain were first found at E40 and were scattered in the arcuate nucleus (AN) and nucleus medialis thalami (NMT). At E50 the extra‐pituitary POMC mRNA was located not only in the AN and NMT but also in the fasciulus tegmenti and entorhinal cortex. In the posterior lobe, no signal was detected. The specific pattern of expression of the pig POMC gene in the pituitary and in specific regions of the central nervous system suggests important roles for POMC in fetal development. These results also suggest that POMC is excellent for studying the expression and regulation of pituitary hormone genes because of its tissue‐specific regulation and developmental pattern.
Intraneuronal Convergence of Tactile and Hormonal Stimuli Associated with Female Reproduction in Rats
Authors: Tetel Marc J. , Celentano Diane C. , Blaustein Jeffrey D. 
Published: September 2006

AbstractStimulation of the vagina and cervix, by mating or manual probing, elicits many behavioral and endocrine changes associated with female reproduction in rats. We and others have identified neurons in the medial preoptic area, medial division of the bed nucleus of the stria terminalis, posterodorsal portion of the medial amygdala, ventromedial hypothalamus, dorsomedial hypothalamus and midbrain central gray that increase Fos expression in response to vaginal‐cervical stimulation (VCS). In the present study, we used a double‐label immunofluorescent technique to determine if any of these VCS‐responsive neurons also contained estrogen receptor‐immunoreactivity. We found that over 80% of the VCS‐induced Fos‐IR neurons in the medial division of the bed nucleus of the stria terminalis also contained estrogen receptor‐immunoreactivity. Furthermore, high percentages of VCS‐responsive neurons in the medial preoptic area, posterodorsal medial amygdala, ventromedial hypothalamus and midbrain central gray contained estrogen receptor‐immunoreactivity as well. These results suggest that sensory and hormonal information associated with female reproduction converge on specific populations of neurons and may be integrated at the molecular level within these neurons.