Search results for " Corticotropin"
showing 10 items of 12 documents
Pituitary-adrenal responses to ovine corticotropin-releasing factor in polycystic ovary syndrome and in other hyperandrogenic patients.
1990
This study was carried out to further characterize the pituitary-adrenal androgen responses of hyperandrogenic patients with 'classic' polycystic ovary syndrome (PCO) and others who were less distinctive and have been called 'PCO-like'. PCO-like patients differed from PCO only in that serum luteinizing hormone (LH) levels were normal and anovulation was not consistent. Ovine corticotropin-releasing factor (CRF) resulted in normal responses of adrenocorticotropic hormone and cortisol in the two groups when compared to controls, while androstenedione (delta 4A) and dehydroepiandrosterone (DHEA) responses were significantly elevated. There were no differences in the responses of PCO and PCO-li…
Diurnal variation of corticotropin-releasing factor binding sites in the rat brain and pituitary.
1996
1. Corticotropin-releasing factor (CRF) is thought to be involved in the regulation of the diurnal activity of the hypothalamus-pituitary-adrenal (HPA) axis and to act as a neurotransmitter in the brain. To date it is unknown whether the binding sites of the central CRF system are subject to diurnal variations. 2. We measured the number of CRF binding sites over the course of a complete 24-hr light-dark cycle in the pituitary, amygdala, bed nucleus of the stria terminalis (BNST), cingulate cortex, visceral cortex, paraventricular nucleus of the hypothalamus, hippocampus, and locus ceruleus of rats by in vitro receptor autoradiography with iodinated ovine CRF. A 24-hr time course was also es…
Early life stress is a risk factor for excessive alcohol drinking and impulsivity in adults and is mediated via a CRF/GABAA mechanism
2016
Childhood stress and trauma are associated with substance use disorders in adulthood, but the neurological changes that confer increased vulnerability are largely unknown. In this study, maternal separation (MS) stress, restricted to the pre-weaning period, was used as a model to study mechanisms of protracted effects of childhood stress/traumatic experiences on binge drinking and impulsivity. Using an operant self-administration model of binge drinking and a delay discounting assay to measure impulsive-like behavior, we report that early life stress due to MS facilitated acquisition of binge drinking and impulsivity during adulthood in rats. Previous studies have shown heightened levels of…
Increased Anxiety-Like Behavior and Ethanol Self-Administration in Dependent Rats: Reversal via Corticotropin-Releasing Factor-2 Receptor Activation
2004
Background: Corticotropin-releasing factor (CRF) has been hypothesized to be one of the main regulators of the stress response observed during alcohol withdrawal. The CRF receptor subtypes seem to have a differential role in the regulation of stress-related behavior. Given the behavioral characterization of these receptors, the objective of the following experiments was to characterize the role of CRF2 receptors in the interaction between alcohol and stress by examining the effects of CRF2 receptor activation in the behavioral stress response and ethanol self-administration during early ethanol withdrawal in dependent rats. Methods: Male Wistar rats were made dependent on ethanol via chroni…
A Polymorphism in the Crhr1 Gene Determines Stress Vulnerability in Male Mice
2014
Chronic stress is a risk factor for psychiatric disorders but does not necessarily lead to uniform long-term effects on mental health, suggesting modulating factors such as genetic predispositions. Here we address the question whether natural genetic variations in the mouse CRH receptor 1 (Crhr1) locus modulate the effects of adolescent chronic social stress (ACSS) on long-term stress hormone dysregulation in outbred CD1 mice, which allows a better understanding of the currently reported genes × environment interactions of early trauma and CRHR1 in humans. We identified 2 main haplotype variants in the mouse Crhr1 locus that modulate the long-term effects of ACSS on basal hypothalamic-pitui…
The gamma(2)-MSH peptide mediates a central analgesic effect via a GABA-ergic mechanism that is independent from activation of melanocortin receptors.
2001
Using the latency for tail-flick after thermal stimulation we have assessed the effects of alpha-, gamma(1)- and gamma(2)-MSH on nociceptive threshold in the mice. Intracisternal injections of gamma(2)-MSH induced a distinct analgesia, while gamma(1)-MSH in the same doses gave only a minor analgesia. Intracisternal alpha-MSH instead gave a short-term hyperalgesia. The effect of gamma(2)-MSH was not blocked by any of the MC(4)/MC(3)receptor antagonist HS014, naloxone or by the prior intracisternal administrations of gamma(1)-MSH. However, the gamma(2)-MSH analgesic response was completely attenuated by treating animals with the GABA(A)antagonist bicuculline. The gamma(2)-MSH analgesic effect…
Role of central oxytocin in the inhibition by endotoxin of distension-stimulated gastric acid secretion
2000
The gastric acid hyposecretory state associated with endotoxemia is mediated by a nervous reflex involving the central nervous system. The aim of the present study was to analyse the central effects of different peptides on distension-stimulated gastric acid secretion and the endogenous role of such peptides on the hyposecretory effects of endotoxin. The effect of an intracisternal (i.c.) administration of oxytocin, vasopressin, corticotropin releasing factor (CRF), bombesin, somatostatin and the opioid receptor agonist BW443C or an intravenous (i.v.) injection of a small dose of endotoxin on distension-stimulated gastric acid secretion was studied in the continuously perfused stomach of an…
Episodic Social Stress-Escalated Cocaine Self-Administration: Role of Phasic and Tonic Corticotropin Releasing Factor in the Anterior and Posterior V…
2016
Intermittent social defeat stress escalates later cocaine self-administration. Reward and stress both activate ventral tegmental area (VTA) dopamine neurons, increasing downstream extracellular dopamine concentration in the medial prefrontal cortex and nucleus accumbens. The stress neuropeptide corticotropin releasing factor (CRF) and its receptors (CRF-R1, CRF-R2) are located in the VTA and influence dopaminergic activity. These experiments explore how CRF release and the activation of its receptors within the VTA both during and after stress influence later cocaine self-administration in rats.In vivomicrodialysis of CRF in the VTA demonstrated that CRF is phasically released in the poster…
Subtype selective binding properties of substituted linear melanocyte stimulating hormone analogues
2002
The melanocortin receptors are peptide binding G-protein coupled receptors that play a role in important physiological functions such as energy balance, inflammatory processes and several aspects of reproduction. In this study, we synthesised 11 new linear MSH analogues and tested their binding to the human MC receptors (MC1, MC3, MC4 and MC5) expressed in COS cells. Our results show that introduction of Asp in position 4 similarly affects the binding to the MC1, MC4 and MC5 receptors, but drastically lowers the binding to the MC3 receptor. Arg(5) substitution shows relatively high affinity for the MC4 receptor, while the results also give further support for specific importance of His(6) f…
Cloning, tissue distribution, pharmacology and three-dimensional modelling of melanocortin receptors 4 and 5 in rainbow trout suggest close evolution…
2004
The rainbow trout (Oncorhynchus mykiss) is one of the most widely used fish species in aquaculture and physiological research. In the present paper, we report the first cloning, 3D (three-dimensional) modelling, pharmacological characterization and tissue distribution of two melanocortin (MC) receptors in rainbow trout. Phylogenetic analysis indicates that these receptors are orthologues of the human MC4 and MC5 receptors. We created 3D molecular models of these rainbow trout receptors and their human counterparts. These models suggest greater divergence between the two human receptors than between their rainbow trout counterparts. The pharmacological analyses demonstrated that ACTH (adreno…