The behaviour of sheep drinking ethanol solution.
Blair-West, J. R., D. R. Deam*, D. A. Denton, E. Tarjan, and R. S. Weisinger.
Howard Florey Institute of Experimental Physiology and Medicine, University
of Melbourne, Parkville, Victoria 3052 and *Biochemistry Department, Royal
Melbourne Hospital, Parkville, Victoria 3050, Australia
APStracts 2:0002R, 1995.
Sheep that were habituated to drinking 10% (v/v) ethanol solution instead of
water were subjected to proven thirst stimuli in order to study the effect of
chronic ethanol intake on brain mechanisms subserving thirst. Sheep that had
not previously drunk 10% ethanol were also tested. All sheep were trained to
press a pedal which delivered 50ml/press of fluid, which was either 10%
ethanol or water, into a drinking cup. In some experiments, fluids were
presented in bins. All animals had access to only one fluid at a time. Five
ethanol-drinking sheep appeared healthy and maintained body weight over 18
months. They always preferred water to 10% ethanol. The
intracerebroventricular (ICV) infusion of angiotensin II (Ang II) at 3.8
[mu]g/h for two hours increased ethanol intake from 15 +/- 10 ml to 200 +/-
55ml in the first hour, but 2,850 +/- 320ml of water was drunk in the second
hour. The ICV infusion of 500 mM NaCl had a similar effect. After fluid
deprivation for 22h or 46h, ethanol intake in one hour of access was only 280
+/- 40ml and 400 +/- 90ml respectively, and 24h intake was not increased.
Water-drinking sheep drank 1300 +/- 195ml of water in one hour after 22h water
deprivation and 24h intake was 1.5 times normal. The ICV infusion of Ang II in
these sheep increased water intake in one hour from 10 +/- 10ml to 1630 +/-
250ml and intake of 10% ethanol to only 310 +/- 60ml. In conclusion, sheep
accept 10% ethanol as a substitute for water for daily drinking. The ICV
infusion of Ang II or 500 mM NaCl stimulated water intake, but these
dipsogenic stimuli or fluid restriction did not evoke avid ethanol intake in
ethanol-drinking sheep. The brain mechanism subserving thirst was unimpaired
by prolonged ethanol intake but 10% ethanol was not acceptable for quenching
thirst.
Received 9 August 1994; accepted in final form 5 January 1995.
APS Manuscript Number R439-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative Comp.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 25 February 1995.