Effect of pairings of pentobarbital with lithium chloride on the capacity of pentobarbital to maintain a conditioned aversion

Rats with conditioned aversions to NaCl water were exposed to either an injection of pentobarbital (Pent) followed 30 min later by an injection of lithium chloride (LiCl) on four separate occasions or to injections of LiCl alone, Pent alone, or LiCl followed by Pent. These injections were followed by pairings of NaCl consumption with injections of Pent. The Pent leads to LiCl pairings eliminated the capacity of Pent to maintain the animals' conditioned aversion to NaCl water relative to the other groups. These findings are consistent with the idea that Pent leads to LiCl pairings cause the Pent state to elicit a compensatory response. This compensatory response seems to eliminate the properties of Pent which normally produce or maintain flavor aversions.