Differences in the response to pentobarbital sodium of Roman high- and low-avoidance rats.

Wistar-derived, Roman high- and low-avoidance rats (RHA and RLA) have been bred solely for divergent patterns of performance in a behavioral test. In the present study, single and multiple injections were used to investigate the acute and chronic effects of pentobarbital sodium in these 2 strains. The median lethal dose was found to be significantly higher for the male RHA rats than for the RLA males. RHA males also had proportionally larger livers, kidneys and hearts, and lower erythrocyte counts, hematocrits and hemoglobin levels than had RLA males.