TRH in dorsal vagal complex mediates acid response to excitation of raphe pallidus neurons in rats.
The role of thyrotropin-releasing hormone (TRH) in the dorsal vagal complex (DVC) in the acid response to excitation of raphe pallidus neurons was investigated in urethan-anesthetized rats with gastric fistula. Kainic acid (0.19 microgram/30 nl) microinjected into the raphe pallidus stimulated gastric acid secretion. The response was prevented by vagotomy. A specific polyclonal TRH antibody, 8964, was raised and characterized (50% inhibitory dose for TRH was 80 pg/ml at an antibody final dilution of 1:10(5)). The TRH antibody injected intracisternally blocked the acid response to intracisternal TRH, but not that of the TRH analogue RX-77368. The TRH antibody (0.33, 0.65, or 1.3 micrograms.100 nl-1.site-1) microinjected bilaterally into the DVC prevented dose dependently by 31, 60, and 76%, respectively, the increase in acid secretion induced by kainic acid injected into the raphe pallidus. The TRH antibody (1.3 microgram/site) microinjected into medullary sites outside of the DVC had no effect. These data indicate that excitation of raphe pallidus neurons induces a vagal-dependent stimulation of gastric acid secretion that is mediated by endogenous TRH in the DVC. TRH neurons in the raphe pallidus projecting to the DVC may have a physiological relevance in the vagal regulation of gastric function.
Yang
H
H
Center for Ulcer Research and Education, Veterans Affairs Wadsworth Medical Center, Los Angeles, California.
Ohning
G
G
Taché
Y
Y
D000818:Animals; D000906:Antibodies / Q000008:administration & dosage / Q000494:pharmacology; D001931:Brain Mapping; D005744:Gastric Acid / Q000378:metabolism*; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D007608:Kainic Acid / Q000008:administration & dosage / Q000494:pharmacology; D008297:Male; D008845:Microinjections; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011903:Raphe Nuclei / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D013973:Thyrotropin-Releasing Hormone / Q000031:analogs & derivatives / Q000276:immunology / Q000494:pharmacology* / Q000502:physiology*; D014628:Vagotomy; D014630:Vagus Nerve / Q000502:physiology*
D000906:Antibodies; D013973:Thyrotropin-Releasing Hormone; C027979:L-pyroglutamyl-L-histidyl-3,3-dimethylprolinamide; D007608:Kainic Acid; D011761:Pyrrolidonecarboxylic Acid