Corticotropin-Releasing Factor Receptor 1 Antagonist Alters Regional Activation and Effective Connectivity in an Emotional-Arousal Circuit during Expectation of Abdominal Pain

Center for the Neurobiology of Stress and Departments of Medicine, Physiology, and Psychiatry, University of California, Los Angeles, Los Angeles, California 90095, USA.
The Journal of Neuroscience : The Official Journal of the Society for Neuroscience (Impact Factor: 6.34). 08/2011; 31(35):12491-500. DOI: 10.1523/JNEUROSCI.1860-11.2011
Source: PubMed


Alterations in corticotropin-releasing factor (CRF) signaling pathways have been implicated in irritable bowel syndrome (IBS) pathophysiology. We aimed to (1) determine the effect of the selective CRF receptor 1 antagonist (CRF(1)) GW876008 relative to placebo, on regional activation and effective connectivity of a stress-related emotional-arousal circuit during expectation of abdominal pain using functional magnetic resonance imaging in human subjects with a diagnosis of IBS and healthy controls (HCs), and (2) examine GW876008 effects on state-trait anxiety and hypothalamic-pituitary-adrenal (HPA) axis response. Although there were no drug-related effects on peripheral HPA activity, significant central effects were observed in brain regions associated with the stress response. Effective connectivity analysis showed drug-induced normalizations between key regions of the emotional-arousal circuit in patients. During pain expectation, orally administered GW876008 relative to placebo produced significant blood oxygen level-dependent (BOLD) signal reductions in the amygdala, hippocampus, insula, anterior cingulate, and orbitomedial prefrontal cortices across groups. Patients showed significantly greater BOLD responses in the left locus coeruleus and hypothalamus after placebo compared with HCs, and BOLD signal decreases in the left hypothalamus after drug. The inhibitory effects of GW876008 in the hypothalamus in patients were moderated by anxiety; patients having average and high levels of state anxiety showed drug-related BOLD decreases. GW876008 represents a novel tool for elucidating the neuronal mechanisms and circuitry underlying hyperactivation of CRF/CRF(1) signaling and its role in IBS pathophysiology. The unique state anxiety effects observed suggest a potential pathway for therapeutic benefit of CRF(1) receptor antagonism for patients with stress-sensitive disorders.

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    • "Both receptors signal through Gs activation of adenylate cyclase and increases in cAMP, but they produce opposite behavioral effects: CRF 1 facilitates and CRF 2 inhibits stress and nociceptive responses in rodent behavioral models (Ji and Neugebauer, 2007, 2008; Yarushkina et al., 2009; Tran et al., 2014). In patients with chronic pain, CRF concentration within the cerebrospinal fluid correlated with pain rating (McLean et al., 2006) and a selective CRF 1 antagonist decreased enhanced amygdala activity and emotional ratings (Hubbard et al., 2011), suggesting that CRF is a valid target for therapeutic intervention in some chronic pain conditions. However, clinical evidence to date has produced mixed effects on pain relief in this therapeutic class (Sagami et al., 2004; Sweetser et al., 2009). "
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    ABSTRACT: While current therapeutics provide relief from acute pain, drugs used for treatments of chronic pain are typically less efficacious and limited by adverse side effects including tolerance, addiction and gastrointestinal upset. Thus, there is a significant need for novel therapies for the treatment of chronic pain. In concert with chronic pain, persistent stress facilitates pain perception and sensitizes pain pathways, leading to a feed-forward cycle promoting chronic pain disorders. Stress-exacerbation of chronic pain suggests that centrally acting drugs targeting the pain and stress responsive brain regions represent a valid target for the development of novel therapeutics. This review will provide an overview of how stress modulates spinal and central pain pathways, identify key neurotransmitters and receptors within these pathways, and highlight their potential as novel therapeutics to treat chronic pain.
    No preview · Article · Sep 2014 · Journal of Pharmacology and Experimental Therapeutics
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    • "The CeA, a limbic region critical for converting emotionally relevant sensory information into appropriate behavioral and physiological responses, has been identified as a potential " on-off " switch for central transmission of pain information (Rouwette et al., 2012). In humans, oral administration of a CRF1R antagonist dampens the amygdalar activation produced by pain expectation (Hubbard et al., 2011). In rats, administration of exogenous CRF into CeA promotes nociception via effects at CRF1Rs (Ji and Neugebauer, 2008). "
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    ABSTRACT: Because tobacco use has a large negative health and financial impact on society, it is critical to identify the factors that drive excessive use. These factors include the aversive withdrawal symptoms that manifest upon cessation of tobacco use, and may include increases in nociceptive processing. Corticotropin-releasing factor (CRF) signalling in the central amygdala (CeA) has been attributed an important role in: (1) central processing of pain, (2) excessive nicotine use that results in nicotine dependence, and (3) in mediating the aversive symptoms that manifest following cessation of tobacco exposure. Here, we describe three experiments in which the main hypothesis was that CRF/CRF1 receptor (CRF1R) signalling in the CeA mediates nicotine withdrawal-induced increases in nociceptive sensitivity in rats that are dependent on nicotine. In Experiment 1, nicotine-dependent rats withdrawn from chronic intermittent (14-h/day) nicotine vapor exhibited decreased hindpaw withdrawal latencies in response to a painful thermal stimulus in the Hargreaves test, and this effect was attenuated by systemic administration of the CRF1R antagonist, R121919. In Experiment 2, nicotine-dependent rats withdrawn from nicotine vapor exhibited robust increases in mRNA for CRF and CRF1Rs in CeA. In Experiment 3, intra-CeA administration of R121919 reduced thermal nociception only in nicotine-dependent rats. Collectively, these results suggest that nicotine dependence increases CRF/CRF1R signalling in the CeA that mediates withdrawal-induced increases in sensitivity to a painful stimulus. Future studies will build on these findings by exploring the hypothesis that nicotine withdrawal-induced reduction in pain thresholds drive excessive nicotine use via CRF/CRF1R signalling pathways.
    Full-text · Article · Oct 2013 · Neuropharmacology
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    • "There is also preliminary evidence that R317573 exerts anxiolytic effects in healthy subjects subjected to 7.5% carbon monoxide inhalation, an experimental model of anxiety [17]. Similarly, in a recent randomized, double-blind, placebo-controlled study, the selective CRF1 antagonist GSK-GW876008 decreased brain regional activity associated with the emotional-arousal network during expectation of abdominal pain in IBS patients [14]. On the other hand, the CRF1 antagonists, CP-316,311, showed no effect against depression in a 6-week randomized, placebo-controlled trial [18] and pexacerfont did not demonstrate efficacy compared to placebo for the treatment of generalized anxiety disorders in a multi-center clinical trial [19]. "
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    ABSTRACT: Corticotropin releasing factor receptor 1 (CRF1) is the key receptor that mediates stress-related body responses. However to date there are no CRF1 antagonists that have shown clinical efficacy in stress-related diseases. We investigated the inhibitory effects of a new generation, topology 2 selective CRF1 antagonists, NGD 98-2 and NGD 9002 on exogenous and endogenous CRF-induced stimulation of colonic function and visceral hypersensitivity to colorectal distension (CRD) in conscious rats. CRF1 antagonists or vehicle were administered orogastrically (og) or subcutaneously (sc) before either intracerebroventricular (icv) or intraperitoneal (ip) injection of CRF (10 µg/kg), exposure to water avoidance stress (WAS, 60 min) or repeated CRD (60 mmHg twice, 10 min on/off at a 30 min interval). Fecal pellet output (FPO), diarrhea and visceromotor responses were monitored. In vehicle (og)-pretreated rats, icv CRF stimulated FPO and induced diarrhea in >50% of rats. NGD 98-2 or NGD 9002 (3, 10 and 30 mg/kg, og) reduced the CRF-induced FPO response with an inhibitory IC50 of 15.7 and 4.3 mg/kg respectively. At the highest dose, og NGD 98-2 or NGD 9002 blocked icv CRF-induced FPO by 67-87% and decreased WAS-induced-FPO by 23-53%. When administered sc, NGD 98-2 or NGD 9002 (30 mg/kg) inhibited icv and ip CRF-induced-FPO. The antagonists also prevented the development of nociceptive hyper-responsivity to repeated CRD. These data demonstrate that topology 2 CRF1 antagonists, NGD 98-2 and NGD 9002, administered orally, prevented icv CRF-induced colonic secretomotor stimulation, reduced acute WAS-induced defecation and blocked the induction of visceral sensitization to repeated CRD.
    Full-text · Article · Sep 2013 · PLoS ONE
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