title: Thyrotropin-releasing hormone: medullary site of action to induce gastric ulcers and stimulate acid secretion.
abstract: This study evaluated the hypothesis that the dorsal motor nucleus (DMN) of the brainstem may mediate the ulcerogenic and acid-stimulatory effects of thyrotropin-releasing hormone (TRH) in rats. To accomplish this, intra-DMN microinjections of TRH (50 and 500 ng) were performed and their effects on acid secretion and gastric ulcer formation evaluated in the pylorus-ligation model. The high (500 ng), but not the low dose of TRH (50 ng) produced gastric glandular lesions in 64% of the rats with a mean severity index (no. of ulcers/rat) of 6.4 +/- 0.98 and significantly increased gastric acid output. The ulcerogenic and gastric secretory response to intra-DMN TRH was site-specific. We conclude that presynaptic TRH fibers may modulate vagal activity at the level of the DMN and propose that descending TRH pathways may play a role in experimental ulcerogenesis through acid hypersecretion.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005744:Gastric Acid / Q000378:metabolism*; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism / Q000503:physiopathology*; D008845:Microinjections; D051381:Rats; D011919:Rats, Inbred Strains; D013276:Stomach Ulcer / Q000139:chemically induced* / Q000378:metabolism; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology / Q000502:physiology*
chemical_list: D013973:Thyrotropin-Releasing Hormone