Effect of Intracerebroventricular Thyrotropin-releasing Hormone on the Gastric Emptying

Kang, Jin Kyung; Kim, Kyung Hwan; Park, In Suh; Kim, Young Soo; Kim, Pum Soo; Pack, Hyo Jin

Abstract

BACKGROUND AND AIMS: Gastric emptying is dependent on nutritive and physical charaeteristics of the ingested material, and external influences including extrnsic nerve supply, specific peptide hormone and neurotransmitters, Thyrotropin-releasing hormone (TRH) is one of the peptide hormones in the brain and is distributed in the brain part that controls gut motility. Recent studies have suggested the possibility that TRH is involved in central nervous regulation of gastric function. In the present study, we investigated the effects of intracerebroventricular (icv) administration of TRH on the gastric emptying in rats using acetaminophen absorption technique.
METHODS
Polyethylene tube was inserted into rat lateral ventricle which is restrained by stereotaxic apparatus. TRH was injected into lateral ventricle via tube 5 minutes before acetaminophen administration. Blood samples were collected 15, 30, 45, 60, 90, and 120 minutes after acetaminophen administration.
RESULTS
The icv injection of TRH enhanced gastric emptying, whereas intravenous injection exerted no effect. TRH-enhanced gastric emptying was blocked by atropine. Desipramine, which blocks the reuptake of norepinephrine into nerve terminal, exerted no effect on TRH-enhanced gastric emptying. Inhibition of gastric acid secretion by cimetidine exerted no effect on TRH-enhanced gastric emptying.
CONCLUSIONS
TRH enhances gastric emptying by central nervous action which is mediated, in part, by cholinergic path-way.