Ethanol self-selection in rats: A distinction between absolute and 95 per cent ethanol

Preference-aversion functions for ethanol solutions prepared with absolute or 95 per cent ethanol were determined in normal, untreated rats. In a second experiment these functions were similarly determined except in this case, after 4 days of ad lib water, a second determination was made in which half the animals were intubated with saline and the others with p-chlorophenylalanine (pCPA), a potent depletor of brain serotonin. In agreement with other studies, the intake of solutions prepared with absolute ethanol was markedly reduced by treatment with pCPA. In marked contrast to this finding, however, was the fact that this compound had little effect on preference-aversion functions for solutions prepared with 95 per cent ethanol. Ethanol intakes during saline intubations were not significantly lower than baseline levels for either group. The observed distinction between absolute and 95 per cent ethanol would seem to be particularly significant since it became apparent only during an experimental treatment and thus could be an important confounding variable in the self-selection study with animals.