AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 1 157-R164, Copyright © 1986 by American Physiological Society
Water drinking induced by gastric secretagogues in pigs
T. R. Houpt, L. C. Weixler and D. W. Troy
Eleven young pigs, feeding and drinking operantly, were tested for drinking
responses to three gastric secretagogues. First, feed was removed for 1 h
before the test period, then a continuous intravenous infusion of saline or
a secretagogue was begun at a priming rate of 0.6 ml/min for the first 10
min, then at 0.3 ml/min for 50 min. Dose rates were the smallest that would
still cause a vigorous gastric secretion. When 0.9% NaCl was infused, the
pigs drank a mean of 54 +/- 11 (SE) ml. The comparable volumes for the
secretagogues were histamine 174 +/- 41 ml (1 microgram . kg-1 . min-1);
pentagastrin 231 +/- 38 ml (0.5 microgram . kg-1 . min-1); and bethanechol
231 +/- 35 ml (1.0-1.5 microgram . kg-1 . min-1). Pretreatment with
cimetidine (300 mg iv) depressed the drinking response to histamine to 30
+/- 10 ml and to pentagastrin to 58 +/- 24 ml. Atropine (2 mg iv) depressed
the response to bethanechol to 28 +/- 16 ml. Differences between responses
to the secretagogues and either control drinking or antagonist-blocked
responses were all significant (P less than 0.001). The results indicate
that gastric secretion could play a role in stimulation of preprandial
water drinking.
