AJP - Gastrointestinal and Liver Physiology, Vol 269, Issue 2 196-G202, Copyright © 1995 by American Physiological Society
Interleukin-1 beta in the dorsal vagal complex inhibits TRH analogue-induced stimulation of gastric contractility
N. S. Morrow, G. Quinonez, H. Weiner, Y. Tache and T. Garrick
Department of Psychiatry, Veterans Affairs Medical Center, West Los Angeles, California, USA.
The effect of murine interleukin-1 beta (mIL-1 beta) microinjected into the
dorsal vagal complex (DVC) on thyrotropin-releasing hormone (TRH) analogue
(RX-77368)-induced stimulation of gastric contractility was examined in
fasted, urethan-anesthetized rats. Gastric corpus contractions were
measured with extraluminal force transducers and analyzed by computer.
Microinjection of RX-77368 (30 ng) into the right DVC with mIL-1 beta
microinjected either into the right (100, 250 pg) or into the left (100,
500 pg) DVC inhibited gastric contractility for 30-120 min postinjection.
Peak suppression of gastric contractility (64-78%) occurred at 50-60 min
postinjection. Microinjection of mIL-1 beta into the DVC at a lower dose
(10 pg) or into sites adjacent to the DVC (100-500 pg) did not suppress the
stimulated gastric contractility pattern. Injection of mIL-1 beta (250 pg)
or 0.1% bovine serum albumin into the DVC alone did not alter basal gastric
contractility. Intracisternal injection of the IL-1 receptor antagonist
(250 ng/10 microliters) abolished the inhibitory effect of mIL-1 beta (250
pg) on gastric contractility. These results demonstrate that mIL-1 beta
acts in the DVC to inhibit vagally stimulated gastric contractility, and
its action is mediated by IL-1 receptors.
