Ethanol-stress interaction: biochemical findings.

Previous research suggested that low doses of ethanol (ETOH) may have a protective effect against stress: We now report confirmation and extension of that preliminary study. Male Sprague-Dawley rats were injected with 0.50 g/kg ETOH (10% w/v) or an equivalent volume of saline and randomly assigned to one of four groups in Experiments I and II (saline-stress, saline-nonstress, ethanol-stress, ethanol-nonstress). In Experiment III, only two groups were tested (ethanol-stress, saline-stress). The stressors consisted of 30 trials (intertrial interval 60 s) of a 2-s duration 0.40 mA foot shock (Experiment I), 90 min restrain stress at 21 degrees C (Experiment II) or 10 min tail-pinch (Experiment III). In Experiments I and II, plasma nonesterified fatty acids (NEFA) were significantly increased in the saline-stress groups compared to the saline-nonstress or ethanol-nonstress groups. In contrast, subjects treated with ETOH and stress had significantly lower levels of plasma NEFA than saline-stress subjects in Experiments I and III. Plasma corticosterone was significantly elevated in response to stress. Subjects in the ethanol-stress groups had significantly lower levels of plasma corticosterone than subjects in the saline-stress group (Experiments I and II). These results suggest that ETOH has some protective effect against stress-induced increases in plasma corticosterone and NEFA. Furthermore, this finding may be generalized to several different types of stressors.