Marked individual variability in heart rate "normalization" by ethanol.

In order to test Kissin's (1974) concept of "normalization" by ethanol (deviant prealcohol parameter values becoming less deviant after alcohol) in nonalcoholics, data on unselected mice and nonalcoholic humans were analyzed. These data were on heart rates (HR) of 1055 HS mice and 24 young adults, measured before and after receiving a dose of ethanol (mice: 1.4g/kg, i.p.;humans: 1.3g/kg, oral). Both mice and humans, on the average, show marked "normalization" inintially low HR usually increasing after alcohol, and initially high HR usually decreasing. The correlation between (1) deviation in HR from the prealcohol mean and (2) change in HR after alcohol was -0.803 for mice and -0.538 for humans. There is very great individual variability, however, in the degree of this normalizing response, some individuals normalizing strongly and others not at all. Although first described in alcoholics, strong normalization by alcohol of several psychophysiological parameters is now known to occur in mice and seems likely to occur in some nonalcoholic humans. The possible relevance of these results to predisposition to alcoholism remains to be shown.