Role Of Corticotropin-releasing Factor Research Articles

Role of CRF1 and CRF2 Receptors in Stress-induced Increase of Intestinal Epithelial Permeability in the Mouse Colon

Background and Aims: Stress is known to increase intestinal permeability, which may contribute to the development of irritable bowel syndrome (IBS) and other intestinal disorders. Corticotropin releasing factor (CRF) has been proven to mediate stress-induced changes in gut function, such as increased colonic motility, ion secretion, and intestinal permeability. Actions of CRF are mediated by two G-protein coupled receptors, CRF1 and CRF2; both are expressed in the intestine. However, the roles of the CRF1 and CRF2 receptors in stress-induced increase of intestinal epithelial permeability remain unknown. Methods: Adult male and female C57BL/6 mice were restrained (1h/d) for five consecutive days. The selective CRF1 and CRF2 receptor antagonists were injected intraperitoneally 15 min prior to the restraint stress. Control mice were kept in their home cages without restraint. After the last restraint stress/control session, the proximal colon was removed, and the mucosa/submucosa preparations were dissected and mounted onto the Ussing Chamber System for the measurement of intestinal permeability. Transepithelial resistance (TER) and FITC-inulin (4kD) flux across the colonic epithelium were used as indicators of paracellular permeability. Horseradish peroxidase (HRP, 40kD) flux was used to measure transcellular permeability. Results: Restraint stress did not alter TER or FITC-inulin flux in male mice. Pretreatment with the CRF1 receptor antagonist NBI 27914 or the CRF2 receptor antagonist antisauvagine-30 had no effect on TER or FITC-inulin flux in male mice. In female mice, restraint stress significantly reduced TER and increased FITC-inulin flux in the proximal colon, which were blocked by NBI 27914 but not by antisauvagine-30. Restraint stress significantly increased HRP flux in both male and female mice. In male mice, pretreatment with NBI 27914 significantly reduced stress-evoked increase of HRP flux, while antisauvagine-30 had no effect. In female mice, both NBI 27914 and antisauvagine-30 significantly reduced stress-evoked increase of HRP flux. Conclusions: Stress evokes different changes in epithelial permeability in the proximal colon of male and female mice. In male mice, stress does not influence paracellular permeability but increases transcellular permeability, which is mediated by the CRF1 receptor. In female mice, stress increases both transcellular and paracellular permeability. Stress-induced increase of paracellular permeability was mediated by the CRF1 receptor, but the increased transcellular permeability was mediated by both CRF1 and CRF2 receptors. University of Wisconsin-La Crosse Undergraduate Research Grant (CS and LB). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Sex differences in androgen receptor, estrogen receptor alpha, and c-Fos co-expression with corticotropin releasing factor expressing neurons in restrained adult mice

Gonadal hormone actions through androgen receptor (AR) and estrogen receptor alpha (ERα) regulate sex differences in hypothalamic-pituitary-adrenal (HPA) axis responsivity and stress-related behaviors. Here we tested whether corticotropin releasing factor (CRF) expressing neurons, which are widely known to regulate neuroendocrine and behavioral stress responses, co-express AR and ERα as a potential mechanism for gonadal hormone regulation of these responses. Using Crh-IRES-Cre::Ai9 reporter mice we report high co-localization of AR in CRF neurons within the medial preoptic area (MPOA), bed nucleus of the stria terminalis (BST), medial amygdala (MeA), and ventromedial hypothalamus (VMH), moderate levels within the central amygdala (CeA) and low levels in the paraventricular hypothalamus (PVN). Sex differences in CRF/AR co-expression were found in the principal nucleus of the BST (BSTmpl), CeA, MeA, and VMH (males>females). CRF co-localization with ERα was generally lower relative to AR co-localization. However, high co-expression was found within the MPOA, AVPV, and VMH, with moderate co-expression in the arcuate nucleus (ARC), BST, and MeA and low levels in the PVN and CeA. Sex differences in CRF/ERα co-localization were found in the BSTmpl and PVN (males>females). Finally, we assessed neural activation of CRF neurons in restraint-stressed mice and found greater CRF/c-Fos co-expression in females in the BSTmpl and periaqueductal gray, while co-expression was higher in males within the ARC and dorsal CA1. Given the known role of CRF in regulating behavioral stress responses and the HPA axis, AR/ERα co-expression and sex-specific activation of CRF cell groups indicate potential mechanisms for modulating sex differences in these functions.

The Role of Corticotropin-Releasing Factor (CRF) and CRF-Related Peptides in the Social Behavior of Rodents.

Since the corticotropin-releasing factor (CRF) was isolated from an ovine brain, a growing family of CRF-related peptides has been discovered. Today, the mammalian CRF system consists of four ligands (CRF, urocortin 1 (Ucn1), urocortin 2 (Ucn2), and urocortin 3 (Ucn3)); two receptors (CRF receptor type 1 (CRF1) and CRF receptor type 2 (CRF2)); and a CRF-binding protein (CRF-BP). Besides the regulation of the neuroendocrine, autonomic, and behavioral responses to stress, CRF and CRF-related peptides are also involved in different aspects of social behavior. In the present study, we review the experiments that investigated the role of CRF and the urocortins involved in the social behavior of rats, mice, and voles, with a special focus on sociability and preference for social novelty, as well as the ability for social recognition, discrimination, and memory. In general, these experiments demonstrate that CRF, Ucn1, Ucn2, and Ucn3 play important, but distinct roles in the social behavior of rodents, and that they are mediated by CRF1 and/or CRF2. In addition, we suggest the possible brain regions and pathways that express CRF and CRF-related peptides and that might be involved in social interactions. Furthermore, we also emphasize the differences between the species, strains, and sexes that make translation of these roles from rodents to humans difficult.

Chemogenetic activation of corticotropin-releasing factor-expressing neurons in the anterior bed nucleus of the stria terminalis reduces effortful motivation behaviors.

Corticotropin-releasing factor (CRF) in the anterior bed nucleus of the stria terminalis (aBNST) is associated with chronic stress and avoidance behavior. However, CRF + BNST neurons project to reward- and motivation-related brain regions, suggesting a potential role in motivated behavior. We used chemogenetics to selectively activate CRF+ aBNST neurons in male and female CRF-ires-Cre mice during an effort-related choice task and a concurrent choice task. In both tasks, mice were given the option either to exert effort for high value rewards or to choose freely available low value rewards. Acute chemogenetic activation of CRF+ aBNST neurons reduced barrier climbing for a high value reward in the effort-related choice task in both males and females. Furthermore, acute chemogenetic activation of CRF+ aBNST neurons also reduced effortful lever pressing in high-performing males in the concurrent choice task. These data suggest a novel role for CRF+ aBNST neurons in effort-based decision and motivation behaviors.

A role of noradrenergic receptors in anxiolytic-like effect of high CRF in the rat frontal cortex

Corticotropin releasing factor (CRF) is a neuropeptide widely distributed in the brain as a hormonal modulator and neurotransmitter. The best known behavioral function of CRF is activation of stress and anxiety via the hypothalamus and limbic structures but the role of CRF in the cortex is still poorly understood. Our previous studies have shown anxiolytic-like effects of high doses of CRF injected into the Fr2 frontal cortex and involvement of CRF1 receptors (R) in that effect. These results seemed to be controversial as most other studies suggested anxiogenic and not anxiolytic effects of CRF1R stimulation. Since stress is associated with adrenergic system, in the present study, we focused on participation of alpha1 and alpha2 or beta adrenergic receptors in the anxiolytic-like effect of CRF. Moreover, we verified whether these effects of CRF in the Fr2 were really connected with CRF1R.Male Wistar rats were bilaterally microinjected with CRF in a dose of 0.2 μg/1 μl/site or with the specific agonist of CRF1R, stressin 1 (0.2–0.0125 μg/1 μl/site) into the Fr2 area. The elevated plus maze (EPM) test was performed 30 min later to assess the anxiolysis. An involvement of noradrenergic receptors in the CRF induced anxiolytic-like effect in the Fr2 was studied by pretreatment with the alpha1 antagonist prazosin, alpha2 agonist clonidine, alpha2 antagonist RS 79948 or beta antagonist propranolol, 20–30 min before CRF. The influence on anxiety was assessed in the EPM test. The results show that anxiolytic behavior after CRF microinjection into the Fr2 area seems to be mainly connected with the CRF1R activation because a similar effect was observed after stressin 1 administration and it was blocked by CRF1R antagonist. The results observed after administration of noradrenergic ligands indicated that anxiolytic effects of CRF in the Fr2 engaged the alpha1 and alpha2 adrenergic receptors but not beta receptors.

Role of CRF 2 Receptors in Colonic Ion Secretion in Response to Stress‐related Peptides

Background and Aims Stress increases intestinal secretion and exacerbates symptoms of irritable bowel syndrome (IBS). Peripherally-derived corticotropin-releasing factor (CRF) is known to mediate stress-induced intestinal secretion, presumably by activation of CRF1 receptors in the gut. The present study aimed to ascertain the role of CRF2 activation in intestinal secretion by three other members of CRF peptide family, urocortin (UCN) 1-3, in wild-type (WT) and CRF2 knockout (Crhr2-/-) mice. Methods Mucosal/submucosal preparations from proximal colon of WT and Crhr2-/- mice of adult male mice were mounted in Ussing chambers for measurement of short-circuit current (Isc) as an indicator of ion secretion. Results The colonic mucosa/submucosa preparations were exposed to different concentrations of UCN1, 2, or 3 (30 nM, 100 nM, 300 nM, and 1 mM) on the basolateral side. All three UCNs evoked increases in colonic ISC (ΔISC) in a dose-dependent manner. The EC50s were 392.64nM for UCN1, 103.28nM for UCN2, and 231.21nM for UCN3. Application of CRF or stressin1 (a selective CRF1 receptor agonist) (30nM – 1mM) also caused increases in ISC with an EC50 of 597.04nM or 588.84nM, respectively. The potency order was therefore UCN2 > UCN3 > UCN1 > stressin1 » CRF. At each concentration tested, UCN3 produced significantly greater ΔISC responses than that caused by stressin1, CRF, UCN1, or UCN2. Involvement of the CRF receptor subtypes in UCN1-3 evoked ΔISC responses was investigated with the selective CRF1 receptor antagonist NBI27914 and the selective CRF2 receptor antagonist antisauvagine-30. Both NBI27914 and antisauvagine-30 significantly suppressed UCN1 (300nM)-induced ΔISC responses (p < 0.05). The ΔISC responses evoked by UCN2 (100nM) and UCN3 (100nM) were significantly suppressed by antisauvagine-30 (p < 0.05 and p < 0.0001, respectively), but were not influenced by NBI27914 (p > 0.05). In the Crhr2-/- mice, UCN2 (1mM) failed to evoke any ΔISC compared with WT controls (p < 0.01). UCN3 (1mM)-evoked ΔISC responses were significantly decreased by 57.21% in the Crhr2-/- mice compared with WT mice (p < 0.05). In contrast, stressin1 (1mM)-evoked ΔISC response did not differ between WT and Crhr2-/- mice (p > 0.05). Conclusions UCN1-3 all caused an increase of colonic ion secretion, which mimicked the effects of stress and CRF. UCN1-induced increase of colonic ion secretion was mediated by both CRF1 and CRF2, whereas UCN2 and UCN3-induced increase of colonic ion secretion was mediated only by CRF2. Since UCN2 and UCN3 have greater potency and efficacy on colonic ion secretion compared with UCN1, CRF, and stressin1, it is logical to conclude that CRF2 receptors played a predominant role in the pro-secretory effects of UCNs.

P.109 Altered maternal care induces sex specific behavioural phenotypes in the offspring: the role of corticotropin-releasing factor in the bed nucleus

The mechanisms which promote divergence in populations of phytophagous insects using alternative hosts depend on the characterization of hosts as different selective scenarios and the modeling of the demographic dynamics of the insect on those hosts. In the Bolivian Yungas forests, the treehopper Alchisme grossa (Hemiptera: Membracidae) utilizes two sympatric Solanaceae hosts, Brugmansia suaveolens and Solanum ursinum. On both hosts, females take care of nymphs during their development and adults use almost exclusively their natal host species. We characterized: 1) the performance of families (mother and nymphs) on both hosts, 2) maternal care across families and hosts, 3) biotic (herbivory, predators and parasites) and abiotic (temperature, relative humidity and luminosity) conditions across hosts and 4) demographic parameters of cohorts living under natural conditions on both hosts using matrix population modelling. The life cycle was longer on B. suaveolens than on S. ursinum. Microenvironmental abiotic and biotic traits differed between hosts. Nevertheless, performance did not differ between hosts and no differences between hosts were found in demographic parameters. None of the environmental variables explained the demographic parameters. Females performed maternal care with the same intensity on both hosts. Taken together with published data on the system, these results suggest that individuals of A. grossa in this study belong to a single population. Colonization of one of these hosts might be a recent event and evolutionary processes that promote ecological adaptation and hence demographic or performance differences have not yet become noticeable.

Tonic Suppression of the Mesolimbic Dopaminergic System by Enhanced Corticotropin-Releasing Factor Signaling Within the Bed Nucleus of the Stria Terminalis in Chronic Pain Model Rats.

Although dysfunction of the mesolimbic dopaminergic system has been implicated in chronic pain, the underlying mechanisms remain to be elucidated. We hypothesized that increased inhibitory inputs to the neuronal pathway from the dorsolateral bed nucleus of the stria terminalis (dlBNST) to the ventral tegmental area (VTA) during chronic pain may induce tonic suppression of the mesolimbic dopaminergic system. To test this hypothesis, male Sprague Dawley rats were subjected to spinal nerve ligation to induce neuropathic pain and then spontaneous IPSCs (sIPSCs) were measured in this neuronal pathway. Whole-cell patch-clamp electrophysiology of brain slices containing the dlBNST revealed that the frequency of sIPSCs significantly increased in VTA-projecting dlBNST neurons 4 weeks after surgery. Next, the role of corticotropin-releasing factor (CRF) signaling within the dlBNST in the increased sIPSCs was examined. CRF increased the frequency of sIPSCs in VTA-projecting dlBNST neurons in sham-operated controls, but not in chronic pain rats. By contrast, NBI27914, a CRF type 1 receptor antagonist, decreased the frequency of sIPSCs in VTA-projecting dlBNST neurons in the chronic pain rats, but not in the control animals. In addition, histological analyses revealed the increased expression of CRF mRNA in the dlBNST. Finally, bilateral injections of NBI27914 into the dlBNST of chronic pain rats activated mesolimbic dopaminergic neurons and induced conditioned place preference. Together, these results suggest that the mesolimbic dopaminergic system is tonically suppressed during chronic pain by enhanced CRF signaling within the dlBNST via increased inhibitory inputs to VTA-projecting dlBNST neurons.SIGNIFICANCE STATEMENT The comorbidity of chronic pain and depression has long been recognized. Although dysfunction of the mesolimbic dopaminergic system has been implicated in both chronic pain and depression, the underlying mechanisms remain to be elucidated. Here, we show that the inhibitory inputs to the neuronal pathway from the dorsolateral bed nucleus of the stria terminalis (dlBNST) to the ventral tegmental area increase during chronic pain. This neuroplastic change is mediated by enhanced corticotropin-releasing factor signaling within the dlBNST that leads to tonic suppression of the mesolimbic dopaminergic system, which may be involved in the depressive mood and anhedonia under the chronic pain condition.

Role of corticotropin-releasing factor on bladder function in rats with psychological stress

Stress-related peptide corticotropin-releasing factor (CRF) and CRF-related peptides are distributed in the peripheral viscera such as the bladder. We investigated the contribution of psychological stress (PS) and CRF on bladder function. Male rats received sham stress (SS) or PS using a communication box method for 120 min every day for 7 days. One group of rats received the intraperitoneal CRF-R1 antagonist antalarmin for 7 days during stress exposure. Mean voided volume per micturition was significantly lower in PS rats compared to SS rats, which was antagonized by antalarmin treatment. Increases in plasma and bladder CRF, and mRNA expressions of bladder CRF, CRF-R1, and M2/3 muscarinic receptors, were found in PS rats. CRF did not influence bladder contraction in itself; however, stress increased the response of muscarinic contraction of bladder strips. These changes were antagonized by antalarmin treatment. In conclusion, PS reinforces M3 receptor-mediated contractions via CRF-R1, resulting in bladder storage dysfunction.

Role of Corticotropin Releasing Factor in the Neuroimmune Mechanisms of Depression: Examination of Current Pharmaceutical and Herbal Therapies.

Approximately 3% of the world population suffers from depression, which is one of the most common form of mental disorder. Recent findings suggest that an interaction between the nervous system and immune system might be behind the pathophysiology of various neurological and psychiatric disorders, including depression. Neuropeptides have been shown to play a major role in mediating response to stress and inducing immune activation or suppression. Corticotropin releasing factor (CRF) is a major regulator of the hypothalamic pituitary adrenal (HPA) axis response. CRF is a stress-related neuropeptide whose dysregulation has been associated with depression. In this review, we summarized the role of CRF in the neuroimmune mechanisms of depression, and the potential therapeutic effects of Chinese herbal medicines (CHM) as well as other agents. Studying the network of CRF and immune responses will help to enhance our understanding of the pathogenesis of depression. Additionally, targeting this important network may aid in developing novel treatments for this debilitating psychiatric disorder.

Protective effects of urocortin 2 against caerulein-induced acute pancreatitis.

Because little is known about the role of corticotropin-releasing factor (CRF) agonists in regulating responses in pancreatitis, we evaluated the effects of urocortin 2 (UCN2) and stressin1 in caerulein-induced acute pancreatitis (AP) model in rats. Male rats were pretreated with UCN2 or stressin1 for 30 min followed by induction of AP with supraphysiologic doses of caerulein. Serum amylase and lipase activity, pancreatic tissue necrosis, immune cell infiltrate, nuclear factor (NF)-κB activity, trypsin levels, and intracellular Ca2+ ([Ca2+]i) were ascertained. UCN2, but not stressin1 attenuated the severity of AP in rats. UCN2, but not stressin1, reduced serum amylase and lipase activity, cell necrosis and inflammatory cell infiltration in AP. NF-κB activity in pancreatic nuclear extracts increased in AP and UCN2 treatment reduced caerulein-induced increases in NF-κB activity by 42%. UCN2 treatment prevented caerulein-induced degradation of IκB-α in the cytosolic fraction as well as increased levels of p65 subunit of NF-κB in the cytosolic fraction. Pancreatic UCN2 levels decreased in AP compared with saline. UCN2 evoked [Ca2+]i responses in primary acinar cells and abolished caerulein-evoked [Ca2+]i responses at 0.1nM, and decreased by ~50% at 1.0nM caerulein. UCN2 stimulation resulted in redistribution of a portion of F-actin from the apical to the basolateral pole. UCN2 prevented the massive redistribution of F-actin observed with supraphysiologic doses of caerulein. UCN2, but not stressin1 attenuated severity of an experimental pancreatitis model. The protective effects of UCN2, including anti-inflammatory and anti-necrotic effects involve activation of the CRF2 receptor, [Ca2+]i signaling, and inhibition of NF-κB activity.

531 - Role of corticotropin-releasing factor on bladder function in rats with psychological stress

531 - Role of corticotropin-releasing factor on bladder function in rats with psychological stress

Concomitant Behavioral, Electrochemical and Electrophysiological Study in Real Time on the Role of CRF and CRF Antagonist(S) in Anxiety and Depression: Possible Association CRF + 5-HT Receptor Antagonists?

Corticotropin releasing factor (CRF) is involved in conditions of anxiety and stress: It stimulates the release of adrenocorticotropin hormone (ACTH). Also, catecholamines increase ACTH release, while serotonin (5-HT) increases both ACTH and CRF.

Corticotropin-releasing factor suppresses glioma progression by upregulation of long non-coding RNA-p21

Corticotropin-releasing factor (CRF) plays a key role in neuroendocrine regulation of hypothalamo-pituitary-adrenal axis under normal condition and stress by binding to CRF receptor1 (CRFR1). CRF and its receptors have been reported in many types of tumors. Little is known about the role of CRF in the development of glioma. And lincRNA-p21 was reported to act as a role in progression of some cancers. The aim of the present study was to investigate the levels of CRF in glioma, and explore the link between CRF and lincRNA-p21 in this disease. In this study, we found CRF mRNA expression was significantly down-regulated in glioma mice. Moreover, CRF could suppress the proliferation of glioma cells and promote the expression of lincRNA-p21. Afterwards, lincRNA-p21 repressed the proliferation and invasion of glioma cells, which was reversed by miR-34c targeted with 3′-UTR. Furthermore, miR-34c decreased the expression of CRFR1 by binding with the 3′-UTR, which interact with CRF to inhibit the proliferation of glioma cells. Together, these results CRF plays as an important role in glioma progression and metastasis through activation of lincRNA-p21, providing a novel insight for the pathogenesis and underlying therapeutic target for glioma.

Role of Corticotropin-Releasing Factor in Cerebellar Motor Control and Ataxia

Cerebellar ataxia, characterized by motor incoordination, postural instability, and gait abnormality [1-3], greatly affects daily activities and quality of life. Although accumulating genetic and non-genetic etiological factors have been revealed [4-7], effective therapies for cerebellar ataxia are still lacking. Intriguingly, corticotropin-releasing factor (CRF), a peptide hormone and neurotransmitter [8, 9], is considered a putative neurotransmitter in the olivo-cerebellar system [10-14]. Notably, decreased levels of CRF in the inferior olive (IO), the sole origin of cerebellar climbing fibers, have been reported in patients with spinocerebellar degeneration or olivopontocerebellar atrophy [15, 16], yet little is known about the exact role of CRF in cerebellar motor coordination and ataxia. Here we report that deficiency of CRF in the olivo-cerebellar system induces ataxia-like motor abnormalities. CRFergic neurons in the IO project directly to the cerebellar nuclei, the ultimate integration and output node of the cerebellum, and CRF selectively excites glutamatergic projection neurons rather than GABAergic neurons in the cerebellar interpositus nucleus (IN) via two CRF receptors, CRFR1 and CRFR2, and their downstream inward rectifier K+ channel and/or hyperpolarization-activated cyclic nucleotide-gated (HCN) channel. Furthermore, CRF promotes cerebellar motor coordination and rescues ataxic motor deficits. The findings define a previously unknown role for CRF in the olivo-cerebellar system in the control of gait, posture, and motor coordination, and provide new insight into the etiology, pathophysiology, and treatment strategy of cerebellar ataxia.

A chimeric approach to evaluate the role of corticotropin releasing factor in alcohol use disorder

A chimeric approach to evaluate the role of corticotropin releasing factor in alcohol use disorder

Assessment of serum level of corticotropin-releasing factor in primary nocturnal enuresis

Primary nocturnal enuresis is one of the sleep related phenomena characterized by disruption in the relationship between arousal and urination. Corticotropin-releasing factor (CRF) is a neurohormone released from the paraventricular nucleus of the hypothalamus into the median eminence to elicit release of adrenocorticotrophin from the anterior pituitary. It may act to modulate autonomic function and behavior in concert with the endocrine effects. Conflicting animal studies about the role of CRF in micturition, either facilitating or inhibiting, have been raised. It was suggested to be a novel target for treatment of urinary disorders based on the finding that manipulation of CRF in the pontine micturition circuit could affect urodynamic function. The aim was to throw light on the possible role of CRF in primary monosymptomatic nocturnal enuresis by assessing its serum level. Twenty-nine children aged 8-14 years complaining of primary monosymptomatic nocturnal enuresis and 16 age- and sex-matched healthy children with good toilet control day and night were recruited to the study. History taking, clinical examination, and assessment of serum CRF levels in the morning and evening (9 a.m. and 9 p.m.) were carried out for all patients and controls. A positive family history of enuresis was detected in 82.8% of enuretic patients. Serum levels of CRF (both morning and evening) were significantly lower in patients than in controls. Several animal studies suggested that CRF in descending projections from Barrington's nucleus to the lumbosacral parasympathetic neurons is inhibitory to micturition, which supports our results and the assumption that reduction of the evening serum CRF level could have a role in the occurrence of primary monosymptomatic nocturnal enuresis. No significant difference was found between morning and evening CRF serum levels in either cases or controls, which negates our assumption of having a rhythmic pattern of release (figure). No correlations with age were found. According to their history, all our enuretic patients were deep sleepers. Deep sleep and difficult arousal were found to have a major role in primary monosymptomatic nocturnal enuresis. It was proposed that CRF function may allow arousal to occur before micturition to facilitate preparative behaviors. A lower CRF level may explain deep-sleep pattern in children with enuresis. CRF was deficient in our enuretic children, which may draw attention to the possible pathophysiological implications in primary nocturnal enuresis (either at the level of loss of inhibitory effect on micturition or lack of arousal in response to bladder distension). Further proof studies are recommended.

Role of Corticotropin Releasing Factor 1 Signaling in Cocaine Seeking during Early Extinction in Female and Male Rats.

Locus coeruleus norepinephrine (LC-NE) and corticotropin releasing factor (CRF) neurons are involved in stress responses, including stress’s ability to drive drug relapse. Previous animal studies indicate that female rats exhibit greater drug seeking than male rats during initial drug abstinence. Moreover, females are more sensitive to the effect of stress to drive drug seeking than males. Finally, LC-NE neurons are more sensitive to CRF in females compared to males. We hypothesized that increased drug seeking in females on extinction day one (ED1) is due to increased response to the stress of early withdrawal and is dependent upon the increased response of LC in females to CRF. We predicted that LC-NE neurons would exhibit Fos activation on ED1, and that blocking CRF1 signaling would decrease drug seeking on ED1 measured by responding on an active lever previously associated with cocaine self- administration. After chronic cocaine self-administration, female and male rats underwent a test for initial extinction responding by measuring lever pressing in the absence of cocaine. Prior to this Extinction Day 1 (ED1) session, rats were injected with vehicle or the selective CRF1 antagonist (CP) to measure effects of CRF antagonism on drug seeking during early abstinence. ED1 increased corticosterone in female rats, in proportion to lever responding in male and female, indicating that ED1 was stressful. Pretreatment with CP decreased cocaine seeking on ED1 more effectively in female compared to male rats. This increase in responding was associated with an increase in activation of LC NE neurons. Together, these findings indicate that stress, and signaling at CRF receptors in LC, may be involved in the increased drug seeking during initial abstinence.

CRF antagonism within the ventral tegmental area but not the extended amygdala attenuates the anxiogenic effects of cocaine in rats

In addition to its initial rewarding effects, cocaine has been shown to produce profound negative/anxiogenic actions. Recent work on the anxiogenic effects of cocaine has examined the role of corticotropin releasing factor (CRF), with particular attention paid to the CRF cell bodies resident to the extended amygdala (i.e., the central nucleus of the amygdala [CeA] and the bed nucleus of the stria terminalis [BNST]) and the interconnections within and projections outside the region (e.g., to the ventral tegmental area [VTA]). In the current study, localized CRF receptor antagonism was produced by intra-BNST, intra-CeA or intra-VTA application of the CRF antagonists, D-Phe CRF(12–41) or astressin-B. The effect of these treatments were examined in a runway model of i.v. cocaine self-administration that has been shown to be sensitive to both the initial rewarding and delayed anxiogenic effects of the drug in the same animal on the same trial. These dual actions of cocaine are reflected in the development of an approach–avoidance conflict (“retreat behaviors”) about goal box entry that stems from the mixed associations that subjects form about the goal. CRF antagonism within the VTA, but not the CeA or BNST, significantly reduced the frequency of approach–avoidance retreat behaviors while leaving start latencies (an index of the positive incentive properties of cocaine) unaffected. These results suggest that the critical CRF receptors contributing to the anxiogenic state associated with acute cocaine administration may lie outside the extended amygdala, and likely involve CRF projections to the VTA.

Cognitive disruptions in stress-related psychiatric disorders: A role for corticotropin releasing factor (CRF)

This article is part of a Special Issue “SBN 2014”.Stress is a potential etiology contributor to both post-traumatic stress disorders (PTSD) and major depression. One stress-related neuropeptide that is hypersecreted in these disorders is corticotropin releasing factor (CRF). Dysregulation of CRF has long been linked to the emotion and mood symptoms that characterize PTSD and depression. However, the idea that CRF also mediates the cognitive disruptions observed in patients with these disorders has received less attention. Here we review literature indicating that CRF can alter cognitive functions. Detailed are anatomical studies revealing that CRF is poised to modulate regions required for learning and memory. We also describe preclinical behavioral studies that demonstrate CRF’s ability to alter fear conditioning, impair memory consolidation, and alter a number of executive functions, including attention and cognitive flexibility. The implications of these findings for the etiology and treatment of the cognitive impairments observed in stress-related psychiatric disorders are described.