EtOH self-administration in anticipation of noise stress in C57BL/6J mice

C57BL/6J mice were studied for self-administration of ethanol (EtOH) during a signal period that preceded delivery of an environmental stressor (noise) in the home cage. Animals were given 5 weeks of conditioning in which a 5-min period of 75-dB pulsed noise (SIGNAL) preceded a 20-min period of more intense, 90-dB pulsed noise (NOISE) five times daily. EtOH (10% w/v) was then provided in a choice procedure, and drink tube contacts were monitored by computer. Mice that had received the 5 weeks of SIGNAL and NOISE pairings showed an increase in EtOH-seeking behavior, as reflected in EtOH tube contacts during the SIGNAL period. The increase was significant as compared to contacts during baseline or QUIET periods and also as compared to contacts during the same period for control (Ctrl) mice that had received only the 75-dB SIGNAL during conditioning. A subsequent test for passive avoidance confirmed that the 75-dB SIGNAL was aversive for mice that had received noise conditioning but not for Ctrl mice. In sum, the results were in accord with a priori predictions that mice would not show increased EtOH tube contacts during occurrence of intense noise itself but would show increased contacts during the signal that preceded noise. These results were interpreted as preliminary evidence that C57BL/6J mice show self-administration of EtOH in anticipation of an environmental stressor.