Lack of tolerance to ethanol-induced motor impairment on accelerod performance in rats

The effect of ethanol on rats was investigated at increasing rates of accel eration for bar rotation speed. Ethanol was given to rats by a liquid diet starting with 2.4% ethanol (v/v) for 3 days. Then the ethanol concentration was increased to 4.8% (v/v) for 3 days and finally to 7.2% (v/v) for 15 da ys. Accelerod performance was recorded before and throughout 20 days of eth anol intake. Mean blood ethanol levels were 266.34 +/- 13.11 and 285.20 +/- 9.77 mg/dl on the 7th and 15th days of ethanol (7.2% v/v) consumption, res pectively, as measured in a parallel group of animals. Ethanol produced sig nificant concentration-dependent impairments in the accelerod performance o f rats. The motor impairment effect of ethanol was most prominent in the te st using the greatest rate of acceleration (from 0 to 79 rpm within 2 min). The impairment effect of ethanol on accelerod performance occurred through out the period of ethanol exposure. Our results indicate that motor impairm ent on the accelerod performance test produced by an ethanol liquid diet de pends on the concentration of ethanol and the rare of acceleration. In addi tion, under free-access conditions accelerod performance may not be a suita ble behavioral test for detecting tolerance development to ethanol in rats. (C) 1999 Elsevier Science Inc.