Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The present experiment investigated the opposite effects of synthetic alpha-MSH and Melatonin on acquisition and extinction of a passive avoidance response (PAR) and on emotionality, as indexed by defecation, in the PA box. It was found that intraperitoneal (IP) administration of alpha-MSH delayed extinction and increased defecation responses whereas IP administration of Melatonin facilitated extinction of the PAR and decreased defecation. The present experiment confirmed MSH-Melatonin opposition on memory and on the defecation response.
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PMID:Effects of melanocyte-stimulating hormone (MSH) and melatonin on passive avoidance and on an emotional response. 88 81

Introduction of a socially naive male rat into the home territory of a resident counterpart results in agonistic interactions, leading to the rapid social defeat of the intruder. Exposure to the aggressive resident produces a stress-response profile consisting of neuroendocrine activation and coping behaviors such as submission. The present studies examined the dependence of these adaptive responses on endogenous brain Corticotropin-Releasing Factor (CRF), a peptide hormone known to coordinate neuronally mediated- and pituitary-adrenal responses to stress. The Elevated Plus-Maze was employed as an animal model of emotionality in which stressors reduce subsequent exploration of open maze arms without walls in favor of enclosed maze arms. A CRF antagonist, alpha-hel CRF9-41, administered intracerebroventricularly (5 and 25 micrograms i.c.v.) immediately post-stress and 5 min prior to maze testing reversed the heightened emotionality produced by the resident exposure stressor. This action paralleled that of an anxiolytic dose of the short-acting benzodiazepine, midazolam (1.5 mg/kg i.p.). Intra-amygdaloid administration of lower doses of the CRF antagonist (125, 250 and 500 ng i.c.) also reversed, dose-dependently, the effect of exposure to an aggressive resident without altering the behavior of unstressed control animals. Further, the enhanced release of ACTH and corticosterone following social conflict was not modified over the short term by the intra-amygdaloid dose of CRF antagonist (250 ng i.c.) which was effective in reversing stress-induced hyper-emotionality. These results suggest that limbic system CRF substrates exert an anxiogenic effect on the exploratory behavior of socially defeated rats via a pituitary-adrenal-independent mechanism.
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PMID:Corticotropin-releasing factor antagonist reduces emotionality in socially defeated rats via direct neurotropic action. 132 98

Our previous study showed that intracerebroventricular (ICV) administration of corticotropin-releasing hormone (CRH) produced a significant increase in locomotor activity at a dose of 1 microgram and slow stereotypy with prominent grooming at a dose of 10 micrograms. In addition, the ICV administration of CRH caused a significant increase in dopamine (DA) and norepinephrine turnover (NE) in various forebrain regions. The present study was designed to investigate the effects of the ICV administration of CRH on cholecystokinin (CCK), neuropeptide Y (NPY), somatostatin (SOM) and gamma-amino butyric acid (GABA) in the rat forebrain. The ICV administration of 1 and 10 micrograms CRH caused a marked reduction in CCK-like immunoreactivity (CCK-LI), NPY-LI and SOM-LI in the medial frontal cortex (MFC) and anterior cingulate cortex (Ant.CC), whereas it induced an increment of NPY-LI in the nucleus accumbens (NAc) and striatum. Increased SOM-LI and decreased NPY-LI were observed in the hippocampus following the ICV administration of CRH at both doses. The ICV administration of CRH caused a significant decrease in the BAGA content in the MFC, ant.CC, NAc and striatum. Taken together with our previous findings, these results indicate that the ICV administration of CRH induced classical neurotransmitter and neuropeptide abnormalities in the central nervous system which resulted increased emotionality, especially anxiety, in rats.
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PMID:The effects of corticotropin-releasing hormone on peptidergic neurons in the rat forebrain. 168 80

Differences between physically active and sedentary men were tested by profile comparison. The study identifies the relative importance of circulating beta-endorphin (BE), atherosclerotic disease risk (ADR) index, and selected components of emotionality in discriminating between physically active and sedentary men. The subjects were psychologically normal and medically healthy middle-aged men. Jogging activity was the subject classification criterion. The data were collected on selected physiological (treadmill), biochemical (blood collected from resting subjects), and psychological (Eysenck and MMPI) variables. The physical fitness score (PFS) was used as an index of fitness. Physically active men with a high PFS (n = 21), when compared to the sedentary men with a low PFS (n = 15), exhibited lower basal plasma BE, lower ADR, lower anxiety index (AI), and lower MMPI depression score (D). Canonical correlation analysis showed that PFS and BE in one set were correlated with D and neuroticism (NS) in another set of variables. Discriminant function analysis showed that the AI was the most powerful discriminator between the physically active and sedentary men, followed by BE and NS. Interestingly, BE and NS exhibited the same magnitude of discrimination power. The ADR exhibited less discrimination power, relative to AI, BE, and NS. In conclusion, the physically active men, compared to the sedentary men in this study, exhibited lower basal plasma BE, which appeared to be associated with less atherosclerotic disease risk, less neuroticism, less anxiety, and less depression.
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PMID:Beta-endorphin and components of emotionality discriminate between physically active and sedentary men. 252 21

The lesions of medial habenular nuclei increased the pain sensitivity, enhanced the analgesic activity of morphine and slightly activated the behavior. The lesion of fasciculus retroflexus, a pathway connecting habenular nuclei with interpeduncular nucleus enhanced the pain sensitivity less markedly, did not change the efficacy of morphine analgesia, but significantly increased the activity of animals. The lesion of interpeduncular nucleus influenced the pain sensitivity to a smallest degree, did not change the analgesic activity of morphine, but dramatically increased the activity of animals. The activation did not resemble the aimless excitation of amphetamine-treated or raphe-lesioned rats, and no signs of increased emotionality or irritability were noted. The results are interpreted as an evidence of habenulo-interpenduncular complex being a part of a system, involved in the regulation of behavioral activity and the sensitivity to the aversive stimuli. These functions are in all probability mediated partly through substance P and met-enkephalin containing neurons, present in these structures.
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PMID:Habenulo-interpeduncular lesions: the effects on pain sensitivity, morphine analgesia and open-field behavior in rats. 390 26

Adult male Fischer-344 rats were dosed sc with 1 or 2.5 mg/kg of triethyl lead chloride (TEL) for 5 consecutive days. One week after the last dose, TEL-exposed rats had decreased Met-enkephalin in the hypothalamus, septum, and frontal cortex, while substance P was decreased in the hippocampus and frontal cortex. Dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) in the caudate nucleus were not altered by TEL nor were serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) in the caudate nucleus, hypothalamus, hippocampus, or frontal cortex. In a second experiment, rats were dosed with 1.75 mg/kg sc for 5 days. Subsequent assay of brain tissue indicated that TEL decreased met-enkephalin levels in the septum of rats one and seven days after cessation of dosing; effects on substance P were not observed. TEL-induced decreases in Met-enkephalin in the septum were temporally associated with increased hot plate latencies. One day after cessation of dosing with TEL, concentration of 5-HIAA in the caudate nucleus, hippocampus, frontal cortex, and brain stem, and 5-HT in the hippocampus and brain stem were increased. Biogenic amine concentrations were not affected in any other region or at any other time postdosing. A third experiment indicated that TEL-induced analgesia could be attenuated by 10 mg/kg chlordiazepoxide or 10 mg/kg of naloxone. The present results suggest that TEL-induced analgesia may be due to alterations in emotionality or reactivity to noxious stimuli, which may be associated with the alteration in delta opiate mechanism in the limbic system, such as the change of septal enkephalin neuronal activities.
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PMID:Correlation of neurochemical and behavioral effects of triethyl lead chloride in rats. 619 48

The neurochemical mechanisms underlying the coincident activation of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system in response to stress remain unclear. Central injection of the neuropeptide bombesin (BN) potently stimulates the release of epinephrine from the adrenal medulla, adrenocorticotropic hormone (ACTH) from the pituitary gland, and elicits behaviors typically associated with increased emotionality and arousal. The current studies assessed whether stress is associated with 1) fluctuations in the endogenous regional levels of BN-like peptides and/or 2) changes in BN receptor density. Male Sprague-Dawley rats received either no treatment or were subjected to acute immobilization stress for 10, 30 or 120 min. Plasma ACTH levels increased in response to stress, peaking at 30 min. BN-like immunoreactivity increased significantly at the hypothalamus and medulla, within 30 min; however with more sustained immobilization (120 min) BN-like immunoreactivity declined to control levels. Levels of BN-like peptides remained unchanged in several other regions, including the hippocampus, striatum, midbrain, pituitary, and pons. Autoradiographic analysis revealed that the density of BN receptor varied in a regionally specific manner. Significant stress related increases in binding were found at the nucleus of the solitary tract (at 30 and 120 min), and at the paraventricular (at 120 min) and arcuate nuclei (at 120 min) of the hypothalamus. These data indicate the BN-like peptides may play a role in the mediation and/or modulation of response to stress.
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PMID:Are bombesin-like peptides involved in the mediation of stress response? 948 9

In order to test the hypothesis that prenatal hormones influence the emotional maturation of the offspring, the hypothalamo-pituitary-adrenal (HPA) axis activity was studied at the end of pregnancy in two rat breeding lines differing consistently in their innate anxiety-related behaviour in the elevated plus-maze. Virgin and pregnant rats were fitted with a chronic jugular vein catheter and tested 5 days later. The high basal level of anxiety-related behaviour (HAB) described in males and females of the HAB breeding line persists in pregnancy as indicated by a significantly reduced number of entries into and time spent on the open arms of the elevated plus-maze between days 18 and 20 of pregnancy compared with pregnant rats of the breeding line with low anxiety-related behaviour (LAB). In general, an increase in anxiety was found in both breeding lines in pregnancy compared with the respective virgin controls. With respect to HPA axis activity, increased basal levels of adrenocorticotropin (ACTH) and corticosterone have been found in pregnant rats of the HAB line compared with pregnant LAB rats. ACTH and corticosterone secretion in response to emotional and complex physical stressors (exposure to the elevated plus-maze and forced swimming, respectively) did not differ between virgin and pregnant rats of either breeding line. However, independent of the inborn emotionality of the animals, a general attenuation in the HPA axis response to stressors and to exogenous CRH could be confirmed in pregnant rats. The basal and stress-induced activity of the hypothalamo-neurohypophysial system secreting oxytocin and vasopressin was also tested, and no differences were found relating to the emotionality or reproductive state of the animals except for a reduced vasopressin secretion in pregnant HAB rats after forced swimming. The elevated basal activity of the HPA axis, including enhanced circulating concentrations of corticosterone in pregnant HAB rats, may influence both the neuroendocrine and emotional development of their offspring. Thus, the passing-on of maternal behavioural characteristics via prenatal, hormonal 'imprinting' has to be considered as a possible contribution to emotional maturation during an individual's development.
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PMID:Increased basal activity of the hypothalamo-pituitary-adrenal axis during pregnancy in rats bred for high anxiety-related behaviour. 980 20

Several novel cyclic MSH analogs were synthesized, and their binding properties were tested on cells transiently expressing the human melanocortin-1 (MC1), MC3, MC4, and MC5 receptors. We discovered a novel substance (HS024) that showed about 20-fold selectivity and very high affinity (Ki = 0.29 nM) for the MC4 receptor. HS024 (cyclic [AcCys3,Nle4,Arg5,D-Nal7,Cys-NH2(11)]alpha-MSH-(3-11)) has a 29-membered atom ring structure that includes an Arg in position 5. HS024 was found to antagonize an alphaMSH-induced cAMP response in cells expressing the human MC1, MC3, MC4, and MC5 receptor DNAs. HS024 also caused a dose-dependent increase in food intake, with a maximum response (4-fold increase) at a 1-nmol dose injected intracerebroventricularly in free feeding rats. We also tested SHU9119, a previously described nonselective MC receptor antagonist, and found HS024 and SHU9119 to have similar potencies for increasing food intake, although SHU9119 appeared to induce more serious side-effects. HS024 increased the food intake of free feeding rats to levels comparable to those in food-deprived rats, indicating that blockade of the MC4 receptor is a highly effective way to increase feeding. Moreover, we tested the effects of intracerebroventricular injections of HS024 in elevated plus-maze and open-field experiments on rats. In these tests, HS024 did not appear to affect emotionality or locomotor activity, suggesting that the MC4 receptor does not mediate the anxiogenic-like and locomotor effects related to the melanocortic peptides.
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PMID:Discovery of a novel superpotent and selective melanocortin-4 receptor antagonist (HS024): evaluation in vitro and in vivo. 983 40

The Syracuse high- and low-avoidance rats, which have been selectively bred for good (SHA/Bru) or poor (SLA/Bru) avoidance learning in a two-way shuttle box, differ in emotionality. This experiment investigated the effect of corticotropin-releasing hormone (CRH), administered centrally (0, 0.1, 0.5, and 1.0 microg), on conditioned suppression and on the hypothalamic-pituitary-adrenocortical system. Three groups of animals were used: SHA/Bru rats conditioned at 0.21 or 0.43 mA and SLA/Bru rats conditioned at 0.21 mA. The results confirm those of previous studies which found that SLA/Bru rats show greater conditioned suppression than the SHA/Bru rats at the low shock intensity and that at 0.43 mA, the SHA/Bru animals acquire a level of conditioning comparable to that of the SLA/Bru animals at 0.21 mA. The results show that the nonlinear behavioral effect of CRH is independent of strain and produces comparable effects in animals of both strains, but only when level of conditioning is equated. Adrenal and plasma concentrations of corticosterone increased in all three groups of animals as a direct linear function of dose of CRH. Both greater levels of conditioning and larger amounts of CRH increase the synthesis of corticosterone more in SHA/Bru animals than in the SLA/Bru animals. Thus, genetic variation, which differentiates the behavioral and endocrinological characteristics of these animals, shows that these effects of CRH can be independent of each other and suggests that some minimal level of conditioned fear is necessary for CRH to exert its anxiogenic effect.
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PMID:Differential behavioral and endocrinological effects of corticotropin-releasing hormone (CRH) in the Syracuse high- and low-avoidance rats. 987 75


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