AJP - Regulatory, Integrative and Comparative Physiology, Vol 266, Issue 6 1868-R1875, Copyright © 1994 by American Physiological Society
Peripheral bombesin decreases gastric vagal efferent activity in part through vagal pathways in rats
E. Yoshida-Yoneda, Y. Tache, H. P. Kosoyan and J. Y. Wei
Veterans Affairs Wadsworth Medical Center, Department of Medicine, Los Angeles, California.
The influence of intravenous (iv) bombesin on multiunit activities recorded
from the ventral gastric branch of the vagus was investigated in
urethan-anesthetized rats. Consecutive injections of bombesin (0.062, 0.62,
6.2, 62, and 620 pmol iv) decreased dose dependently gastric vagal efferent
discharges to 79.8 +/- 4.9, 68.3 +/- 10.2, 47.0 +/- 6.7, 41.6 +/- 4.7, and
36.5 +/- 8.9%, respectively, from preinjection levels. Saline injection had
no effect. Bombesin (62 pmol iv) reduced cervical vagal efferent discharges
to 25 +/- 6% before and 67 +/- 5% after bilateral cervical vagotomy distal
to the recording site. Bombesin (62 and 620 pmol iv) increased gastric
vagal afferent discharges by 45 and 93%, respectively. These data show that
systemic injection of bombesin potently decreases gastric and cervical
vagal efferent activity in part through vagal-dependent mechanisms that may
involve the increase in gastric vagal afferent activity.
