Acute and chronic alcohol-cocaine interactions in rats

The widespread combined use of alcohol and cocaine across the United States underscores the importance of understanding how the actions of those two a gents interact upon important physiological regulatory processes. In an exp eriment exploring acute ethanol-cocaine interactions, 16 rats were given 2. 0 g/kg (IP) doses of ethanol at time zero. Two hours later, half of the rat s were given cocaine (20 mg/kg, IP), while the other half were given inject ions of saline. The group given cocaine displayed a prolongation of the hyp othermia condition induced by ethanol injection. In a chronic experiment, t hree groups of rats (n = 6-8) were exposed for an 11-day period to daily IP injections of 10 mg/kg cocaine, 20 mg/kg of cocaine, or saline. On day 12 these groups did not differ in their response to loss of the righting refle x induced by a 3.0 g/kg dose of ethanol. However, recovery from ethanol hyp othermia was more rapid in the rats exposed to chronic cocaine. In summary, these initial studies provide evidence for exacerbation of the acute hypot hermic effects of ethanol when a cocaine challenge is given 2 h after ethan ol. In contrast, ethanol hypothermia was observed to be reduced when tested on day 12 after an Ii-day chronic regimen of cocaine. Other dosage regimen s and response measures need to be tested to understand the full scope of a cute and chronic cocaine-ethanol interactions and the possible health conse quences. (C) 1998 Elsevier Science Inc.