Glossopharyngeal nerve transection does not compromise the
specificity of taste-guided sodium appetite in rats.
Markison, Stacy, Steven J. St. John, and Alan C. Spector.
Department of Psychology, University of Florida, Gainesville, FL
32611-2205
APStracts 2:0034R, 1995.
The chorda tympani nerve (CT) has been shown to be critical in the
sodium specific drinking behavior of sodium-depleted rats, but the
role of other gustatory nerves and the contribution of the major
salivary glands remains to be elucidated. In this study, rats
received either bilateral section of the CT (CTX), the
glossopharyngeal nerve (GLX), extirpation of the sublingual and
submaxillary salivary glands (DSAL), or sham surgery. Following
recovery, rats were sodium depleted with furosemide and tested for
their licking responses to 0.05 and 0.3 M NaCl, KCl, CaCl2, and
NH4Cl, as well as distilled water in a computerized gustometer. Rats
that received GLX maintained a specific sodium appetite, comparable
to controls, despite denervation of _64% of the taste buds. In
contrast, CTX and DSAL rats had altered response profiles, showing
much smaller differences in licking to NaCl relative to the other
stimuli as compared with control rats. This was accompanied by a
substantially lower lick rate in DSAL rats, raising the possibility
that general licking impairments contributed to the decreased NaCl
responsiveness in these rats. These findings imply that the CT, but
not the GL, is necessary for the maintenance of sodium specific,
taste-guided behavior under sodium deplete conditions.
Received 10 November 1994; accepted in final form 30 January
1995.
APS Manuscript Number R645-4.
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.