THE ROLE OF CONDITIONED TASTE-AVERSION IN THE HYPOPHAGIA INDUCED BY INTRAPERITONEAL EPINEPHRINE AND GLUCOSE

It has been repeatedly shown that relatively high doses of epinephrine (E) and glucose (G) injected intraperitoneally (ip) produce hypophagi a in fasted rats. In the present work we used a conditioned taste aver sion (CTA) paradigm in order to test whether this effect could be due to ''malaise.'' We determined the effect on food intake and saccharin preference with the following treatments: (a) E ip too and 250 mu g/kg ; (b) E ip 250 mu g/kg with or without previous alpha 1 plus beta adre nergic blockade; (c) G ip 3.5 and 4 g/kg. Both doses of E significantl y reduced food intake more than 75% but only the high dose produced a significant (50%) reduction in saccharin preference. Blockade of alpha 1 and beta adrenergic receptors completely suppressed the E-induced h ypophagia but attenuated only slightly the taste aversivon effect. Bot h doses of G decreased food intake but only the high dose reduced sacc harin preference; part of these effects would appear to be due to the high osmolarity of the solution. The present results indicate that E a nd G may induce CTA in our experimental conditions. However, their hyp ophagic and aversive effects seem to be elicited by different mechanis ms. (C) 1995 Academic Press, Inc.