Pharmacological effects on two inbred substrains of AB mice.

Mice of the two substrains AB/Gat and AB/Hal from the Jena AB inbred strain differ in behavior from each other by their aggressiveness occurring especially in the latter group after maturity. In order to ascertain the neurobiological background of aggressiveness, we injected mice of both substrains with either haloperidol, diazepam, or hexobarbital and measured their response on motor activity. In a second experiment, the reaction to a seizure evoking agent (pentylenetetrazol) was determined. Mice of both substrains were found to differ significantly in their reaction to haloperidol or diazepam injection. In contrast to that no changes in motor activity could be detected following hexobarbital administration. Animals of the aggressive AB/Hal substrain reacted more pronounced to pentylenetetrazol than those of the AB/Gat group. In conclusion, the varying aggressiveness of both AB mice substrains may be due to differences in dopaminergic and GABAergic neurotransmission.