A possible 5-HT3 component of thyrotropin-releasing hormone-induced increases in gastric motility in developing rats.
Intracisternal injection of thyrotropin-releasing hormone (TRH) increases gastric motility primarily via a vagal cholinergic mechanism. However, a serotonergic (5-HT) component may also exist. Rats (7, 10, 14, and > or = 50 days of age) were anesthetized and gastric motility monitored via an extraluminal strain gauge. Following baseline, ICS 205-930 which blocks 5-HT3 and 5-HT4 receptors (0.01, 0.10, or 1.0 mg/kg) was administered intraperitoneally, then 30 min later intracisternal TRH (5 or 10 micrograms). ICS 205-930 0.1 and 1.0 mg/kg blocked TRH-induced motility in 7-day-old rats. Results support a 5-HT3 or 5-HT4 receptor contribution to TRH-induced gastric motility stimulation, and suggest that receptor expression is dynamic during development.
Heitkemper
M M
MM
Department of Physiological Nursing, University of Washington, Seattle 98195.
Bond
E F
EF
Gruver
M K
MK
Horita
A
A
D000818:Animals; D004064:Digestive System / Q000254:growth & development; D004305:Dose-Response Relationship, Drug; D005260:Female; D005769:Gastrointestinal Motility / Q000187:drug effects / Q000502:physiology*; D007211:Indoles / Q000494:pharmacology; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology; D011247:Pregnancy; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D012702:Serotonin Antagonists / Q000494:pharmacology; D013268:Stimulation, Chemical; D013270:Stomach / Q000187:drug effects / Q000254:growth & development* / Q000502:physiology; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D000077526:Tropisetron
D007211:Indoles; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin; D013973:Thyrotropin-Releasing Hormone; D000077526:Tropisetron