Sensitivity to ethanol-induced motor incoordination in FAST and SLOW selectively bred mice

Earlier studies using the grid test have indicated a negative genetic corre lation between sensitivity to ethanol-induced locomotor stimulation and eth anol-induced motor incoordination in FAST and SLOW mice, lines selectively bred for differential sensitivity to ethanol's stimulant effects. Because d ifferent tests of motor coordination may not measure the same behavioral co mpetencies or physiological substrates, the present experiments tested adul t ethanol- or saline-exposed FAST and SLOW mice of two replicates (FAST-1, FAST-2, SLOW-1, and SLOW-2) using three additional tests of coordination: a stationary dowel, fixed-speed rotarod, and accelerating rotarod. After eth anol treatment, FAST-1 mice fell from the stationary dowel at shorter laten cies than SLOW-1 mice, suggesting that they had relatively greater sensitiv ity to ethanol. However, brain ethanol concentrations (BrECs) were similar at time of fall, and no differences were found between replicate-2 lines. S LOW-1 mice fell from the fixed-speed rotarod at lower BrECs than FAST-1 mic e, suggesting possibly greater sensitivity of the SLOW-1 line. Again, no re plicate-2 line differences were found. No significant differences were dete cted for the accelerating rotarod. These results provide little support for a negative genetic relationship between sensitivity to the stimulant and a taxic effects of ethanol using these measures of motor coordination. (C) 20 00 Elsevier Science Inc.