title: Water-avoidance stress enhances gastric contractions in freely moving conscious rats: role of peripheral CRF receptors.
abstract: BACKGROUND
  Stress alters gastrointestinal motility through central and peripheral corticotropin-releasing factor (CRF) pathways. Accumulating evidence has demonstrated that peripheral CRF is deeply involved in the regulation of gastric motility, and enhances gastric contractions through CRF receptor type 1 (CRF1) and delays gastric emptying (GE) through CRF receptor type 2 (CRF2). Since little is known whether water-avoidance stress (WAS) alters gastric motility, the present study tried to clarify this question and the involvement of peripheral CRF receptor subtypes in the mechanisms.
  
  
  METHODS
  We recorded intraluminal gastric pressure waves using a perfused manometric method. The rats were anesthetized and the manometric catheter was inserted into the stomach 4-6 days before the experiments. We assessed the area under the manometric trace as the motor index (MI), and compared this result with those obtained 1 h before and after initiation of WAS in nonfasted conscious rats. Solid GE for 1 h was also measured.
  
  
  RESULTS
  WAS significantly increased gastric contractions. Intraperitoneal (ip) administration of astressin (100 μg/kg, 5 min prior to stress), a nonselective CRF antagonist, blocked the response to WAS. On the other hand, pretreatment (5 min prior to stress) with neither astressin2-B (200 μg/kg, ip), a selective CRF2 antagonist, nor urocortin 2 (30 μg/kg, ip), a selective CRF2 agonist, modified the response to WAS. These drugs did not alter the basal MI. WAS did not change GE.
  
  
  CONCLUSIONS
  WAS may activate peripheral CRF1 but not CRF2 signaling and stimulates gastric contractions without altering GE.
authors: Department of Regional Medicine and Education, Asahikawa Medical University, Midorigaoka Higashi 2-1-1-1, Asahikawa, 078-8510, Japan, tnozu@sea.plala.or.jp.
authors: Tsukasa
authors: T
authors: Nozu
authors: Shima
authors: S
authors: Kumei
authors: Kaoru
authors: K
authors: Takakusaki
authors: Toshikatsu
authors: T
authors: Okumura
mesh_terms: D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000494:pharmacology; D005746:Gastric Emptying / Q000502:physiology; D005753:Gastric Mucosa / Q000378:metabolism*; D005769:Gastrointestinal Motility / Q000502:physiology; D008297:Male; D008365:Manometry; D009119:Muscle Contraction / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D018019:Receptors, Corticotropin-Releasing Hormone / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013315:Stress, Psychological / Q000378:metabolism*; D054832:Urocortins / Q000494:pharmacology; D014867:Water; D000099052:CRF Receptor, Type 1
chemical_list: C101531:CRF receptor type 2; D010446:Peptide Fragments; D010456:Peptides, Cyclic; D018019:Receptors, Corticotropin-Releasing Hormone; D054832:Urocortins; C528574:astressin-2B; D014867:Water; C104416:astressin; D000099052:CRF Receptor, Type 1; D003346:Corticotropin-Releasing Hormone
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