Harmaline-induced tremor: the benzodiazepine receptor as a site of action.

Harmaline produces a tremor which is prevented by diazepam. This beta-carboline also displaces specifically bound 3H-flunitrazepam from the benzodiazepine receptor. While harmaline has a low affinity for the receptor (IC50 approximately 600 micro M), tremorogenic (i.p.) doses of harmaline produce brain concentrations sufficient to occupy some benzodiazepine binding sites. It is suggested that part of harmaline's actions may be the results of an interaction with the benzodiazepine receptor.