Neural and behavioral responsivity to ethyl alcohol as a tastant

Three experiments were designed to study the sensory properties of ethyl alcohol (EtOH) in the rat. In Experiment 1, a conditioned taste aversion (CTA) was produced to 3%, 6% or 9% EtOH. None of these aversions generalized to any of the 4 basic tastants. However, rats in the 6% and 9% EtOH groups did generalize the CTA to a mixture of sucrose-QHCl but not to a mixture of NaCl-HCl. In Experiment 2, a CTA was produced to 6% EtOH and animals were then tested with all 6 combinations of the basic tastants. The CTA was found to generalize significantly to sucrose-QHCl and marginally to sucrose-HCl. In Experiment 3, single unit responses to gustatory stimuli were recorded in the nucleus of the tractus solitarius. Solutions of NaCl, HCl, sucrose, QHCl, 6% and 9% EtOH were bathed over the rostral tongue through a plastic flow chamber. Approximately half of the units responded to 9% EtOH. Analysis of the across-unit patterns of response revealed a weak relationship between responses to EtOh and sucrose in the first 1.0 sec of response.