Effects of intra-amygdalar thyrotropin releasing hormone (TRH) and its antagonism by atropine and benzodiazepines during stress ulcer formation in rats.
Bilateral intra-amygdalar (i/am) microinjections of TRH (1 and 10 micrograms) and physostigmine (10 micrograms) into the central nucleus (CEA) aggravated cold restraint stress (3 hr at 4 degrees C) induced gastric ulcer formation in rats, whereas atropine (1, 5 and 10 micrograms) attenuated this phenomenon. Similar stress ulcer reducing effects were seen with chlordiazepoxide (CDP, 10 mg/kg, IP) and midazolam (1, 3 and 10 micrograms, i/am). Pretreatment of rats with atropine or CDP antagonized the ulcerogenic effects of both TRH and physostigmine. Further, when administered intra-CEA, midazolam neutralized the effects of TRH in a dose-related manner. These results are discussed in light of TRH-acetylcholine-benzodiazepine/GABA interactions within the amygdaloid complex during stress ulcer formation.
Ray
A
A
Neuroscience Laboratory, St. Francis Xavier University, Antigonish, Nova Scotia, Canada.
Henke
P G
PG
Sullivan
R M
RM
D000679:Amygdala / Q000187:drug effects*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002707:Chlordiazepoxide / Q000494:pharmacology; D004347:Drug Interactions; D008297:Male; D008874:Midazolam / Q000494:pharmacology; D010830:Physostigmine / Q000633:toxicity; D051381:Rats; D011919:Rats, Inbred Strains; D012149:Restraint, Physical; D013276:Stomach Ulcer / Q000209:etiology / Q000473:pathology*; D013312:Stress, Physiological / Q000150:complications* / Q000473:pathology; D013973:Thyrotropin-Releasing Hormone / Q000037:antagonists & inhibitors / Q000633:toxicity*
D013973:Thyrotropin-Releasing Hormone; D002707:Chlordiazepoxide; D001285:Atropine; D010830:Physostigmine; D008874:Midazolam