CROSS-GENERALIZATION OF AN ETOH HANGOVER CUE TO ENDOGENOUSLY AND EXOGENOUSLY INDUCED STIMULI

Twenty male Sprague-Dawley rats were trained in a two-choice food-rein forced drug discrimination task (10 min sessions) using the state-depe ndent interoceptive stimulus attributes of ethanol's (EtOH) delayed or rebound effects (EDE) versus ''normal'' basal homeostasis. Cross-gene ralization tests were conducted with 0.18 mg/kg naloxone injected afte r three days of three injections per day of either SAL or 10 mg/kg mor phine. Naloxone failed to generalize to the EDE-state after chronic sa line; however, the precipitated morphine withdrawal state produced com plete generalization to the EDE training cue. Daily tests were conduct ed after 8 h photoperiod phase-shifts. An 8 h phase-advance, equivalen t to a west-to-east intercontinental night-time flight in humans, prod uced a biphasic, graded, increase in EDE-appropriate responding, which peaked on the second day after the phase-advance and recovered by the fourth day. The 8 h phase-delays failed to engender significant EDE-a ppropriate responding. These data provide evidence for the subjective similarity between EtOH hangover, opiate withdrawal states, and the ph ysiological disruption induced by circadian phase-advances. (C) 1997 E lsevier Science Inc.