[3H]-Flunitrazepam binding in the presence of beta-phenylethylamine and its metabolites.

It has recently been reported that the concentration of beta-phenylethylamine (PEA) was elevated in the plasma of an individual experiencing convulsions because of an overdose of tranylcypromine. Also, high concentrations of PEA, injected into mice, were reported to induce convulsions. This convulsive effect was prevented by pretreatment with the benzodiazepines diazepam and chlordiazepoxide. In this study, PEA in concentrations from 0.5 to 100 microM failed to alter the binding of [3H]-flunitrazepam ([3H]-FLU) in membrane preparations from mouse rostral forebrain. The metabolites of PEA: phenylacetic acid, phenylethanolamine, octopamine and tyramine, also failed to affect [3H]-FLU binding. This suggests that although there are substances that act as convulsants by interacting with the benzodiazepine receptor sites, the convulsant effect of PEA and its metabolites is mediated elsewhere.