Voluntary alcohol and cocaine consumption in "low" and "high" stress plasma catecholamine responding rats

Alcohol (ethanol) and cocaine preference in a free-choice, two-bottle situation was measured in two groups of male and female "low" and "high" plasma catecholamine stress responding rats. Alcohol intake of a 5% solution (percent or mg/kg) showed markedly different but individually consistent intake among animals. "High" plasma catecholamine stress responders consumed more ethanol than did "low" responders. A similar finding was made when animals consumed a 10% solution; fluid intake fell but total ethanol intake remained the same. "High" responders drank more than did "low" responders. After a period of 4 weeks of water only, animals were reexposed to 5% ethanol and a significant positive correlation was seen in the drinking habits of the animals. Afterwards, exposure to a 0.02% cocaine solution resulted in cocaine intake which varied among animals, but was consistent for an individual rat and did not correlate with alcohol consumption. In general, ethanol and cocaine consumption correlated positively with the plasma catecholamine stress response. No significant differences in drinking habits were observed between the sexes. Thus, alcohol preference is a relatively stable characteristic of an animal, is higher in "high" as compared to "low" plasma catecholamine stress responders and does not correlate with voluntary cocaine consumption.