Audiogenic seizures: increased benzodiazepin receptor binding in a susceptible strain of mice.

Brain benzodiazepine receptor binding was determined in two inbred strains of mice, one of which is susceptible to audiogenic seizures. Specific binding of 3H-flunitrazepam was higher in the seizure-susceptible DBA/2J strain (at about 22 days of age) when compared to age-matched, seizure-resistant C57BL/6J mice. Like seizure susceptibility, the differences in benzodiazepine binding were age-related. The DBA/2J strain had higher benzodiazepine binding whether convulsed or not. In well-washed brain membrane fragments specific 3H-flunitrazepam binding was also higher in the DBA/2J strain suggesting that the difference was not due to the presence of an endogenous ligand. The higher benzodiazepine binding in the DBA/2J strain was due to a higher benzodiazepine receptor density (Bmax) in this strain. These results suggest that a disorder of the GABA/benzodiazepam receptor complex may be involved in the seizure susceptibility of the DBA/2J strain.