title: Injection of corticotropin-releasing hormone into the amygdala aggravates visceral nociception and induces noradrenaline release in rats.
abstract: BACKGROUND
  Corticotropin-releasing hormone (CRH) and its receptor 1 (CRH-R1) play an important role in the colonic response to stress. The central nucleus of the amygdala (CeA) is a major extrahypothalamic site that contains a large number of neurons expressing both CRH and CRH-R1. Here, we verified the hypothesis that CRH in the CeA sensitizes visceral nociception via CRH-R1 with release of noradrenaline, dopamine, and serotonin (5-HT) in the CeA.
  
  
  METHODS
  In male Wistar rats, visceral sensitivity was quantified by recording the visceromotor response to colorectal distension (CRD) with administration of vehicle, CRH, or the CRH-R1 antagonist CP-154526+ CRH or CRH-R1 antagonist CP-154526 alone into the CeA. Simultaneously, extracellular levels of noradrenaline, dopamine, and 5-HT were measured in the CeA using microdialysis. All data were obtained under restraint conditions.
  
  
  RESULTS
  Administration of CRH into the CeA significantly increased the number of abdominal muscle contractions in response to CRD. CP-154526 significantly blocked the number of abdominal muscle contractions in response to CRD with the administration of CRH into the CeA. Noradrenaline in the CeA was increased by CRD, further increased by CRH, and inhibited by CRH-R1 antagonist. Dopamine in the CeA was also exaggerated by CRH but was not inhibited by CRH-R1 antagonist. 5-HT in the CeA was unchanged.
  
  
  CONCLUSIONS
  These results suggest that CRH in the CeA sensitizes visceral nociception via CRH-R1 with release of noradrenaline.
authors.affiliation: Department of Behavioral Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Su
authors.forename: Y
authors.initials: Y
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Muratsubaki
authors.forename: M
authors.initials: M
authors.lastname: Kano
authors.forename: M
authors.initials: M
authors.lastname: Kanazawa
authors.forename: S
authors.initials: S
authors.lastname: Fukudo
mesh_terms: D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D003106:Colon / Q000473:pathology; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000502:physiology*; D004108:Dilatation, Pathologic; D004298:Dopamine / Q000378:metabolism; D008297:Male; D059225:Nociception / Q000502:physiology*; D009638:Norepinephrine / Q000378:metabolism*; D011743:Pyrimidines / Q000494:pharmacology; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D018019:Receptors, Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors; D012007:Rectum / Q000473:pathology; D012701:Serotonin / Q000378:metabolism
chemical_list: C101628:CP 154526; D011743:Pyrimidines; D011758:Pyrroles; D018019:Receptors, Corticotropin-Releasing Hormone; D012701:Serotonin; D003346:Corticotropin-Releasing Hormone; D004298:Dopamine; D009638:Norepinephrine
keywords: CRD; brain-gut interaction; central amygdaloid nucleus; dopamine; noradrenaline; serotonin