Investigating benzodiazepine receptor function in vivo using an intravenous infusion of DMCM.

A method for measuring seizure thresholds using an intravenous infusion of a convulsant beta-carboline benzodiazepine receptor ligand (DMCM) is reported. Seizure thresholds to DMCM are elevated by the benzodiazepine receptor agonist, flurazepam and antagonist, Ro 15-1788, and the proconvulsant beta-carboline, FG 7142. Various other anticonvulsant also antagonise DMCM seizures. Selectivity for the benzodiazepine/GABA receptor complex is demonstrated since bicuculline and pentylenetetrazol lowered thresholds whereas strychnine and N-methyl DL-aspartate did not.