[N-methyl-3H]methylphenazepam--a new ligand for benzodiazepine receptors].

The binding of [N-methyl-3H] methylphenazepam with synaptosomal membranes of rat striatum was studied. The affinity of binding sites to this ligand was higher when compared with [3H] diazepam. No changes in maximal binding capacity were found in two groups. GABA and muscimol increased the binding of [3H] diazepam and had no effect on binding of [N-methyl-3H] methylphenazepam. Diazepam and phenazepam competitively decreased the [N-methyl-3H] methylphenazepam binding. The inhibitor activity of phenazepam was higher.