Taste reactivity responses elicited by reinforcing drugs: a dose-response analysis.

A series of 3 experiments with Sprague-Dawley rats measured taste reactivity (TR) responses elicited by sucrose that was paired on 5 occasions with various doses of d-amphetamine (0, 1, 2, 5, or 10 mg/kg), nicotine (0, 0.4, 0.8, 1.2, or 2.0 mg/kg), or morphine (0, 2, 8, 20, or 80 mg/kg). The TR responses elicited by flavors paired with each of these drugs were compared with those elicited by flavors paired with lithium. The only doses of d-amphetamine and nicotine that effectively conditioned aversive TR responses were high doses that have also been demonstrated to be incapable of producing a place preference. Extremely high doses of morphine were incapable of producing aversive TR responses. It is suggested that aversive TR responses are only produced by doses of agents that are not reinforcing in other paradigms.