Mice selected for differences in sensitivity to a benzodiazepine receptor inverse agonist vary in intermale aggression.

Brain y-aminobutyric acid (GABA) levels ars involved in intermale aggression in mice. It was therefore expected that animals genetically selected for their sensitivity to the convulsive effects of methyl B-carboline-3-carboxylate IB-CCM; BS, B-CCM sensitive, and BR, B-CCM resistant), a benzodiazepine (BZ) inverse agonist that specifically binds to the BZ site on the GABA-A receptor complex, would differ in their levels of aggressive behavior. Using two different aggression tests, in two independent experiments, we showed that BS mice are more aggressive than BR animals. The precise mechanisms underlying the observed line differences in B-CCM sensitivity and aggression remain to be determined