CYCLIC-AMP TASTES AVERSIVE, NOT SWEET, TO RATS

Electrophysiological and biochemical evidence suggests that cAMP media tes sweet taste transduction. Neural recordings from anesthetized rats and in vitro preparations demonstrate that membrane-permeable cAMP an alogues mimic the effects of sucrose and artificial sweetners. We pres ented solutions of sodium 8-(4-chlorophenylthio)-adenosine 3'-5'-cycli c monophosphate (8cpt-cAMP), a water-soluble, membrane-permeable cAMP analogue to freely behaving rats in short-term lickometer tests. Rats licked significantly less to 8cpt-cAMP than to sucrose or palatable sa ccharin solutions. Rats could taste 8cpt-cAMP solutions, however, beca use they licked less to 8cpt-cAMP in mixture with sucrose than to sucr ose alone. Because 8cpt-cAMP decreased licking when mixed with sucrose , we conclude that the taste of 8cpt-cAMP is aversive, not sweet, to f reely behaving rats.