[Effect of diazepam on the specific binding of 3H-(D-Ala-2, D-Leu-5)-enkephalin by striatal membranes in the rat].

The effect of a single intraperitoneal administration of diazepam (relanium) (2.5 mg/kg) on specific binding of 3H-(D-Ala-2, D-Leu-5)-enkephalin (10 nM) by the rat striatum membranes was studied. The drug was shown to increase the binding activity of opioid receptors 15 minutes after the injection. At prolongation of the animal exposure by up to 45 minutes the magnitude of the activity decreases below the control level. Under in vitro conditions diazepam shows the activating effect which is similar to that ex vivo. It was found that the changes in the opioid receptor binding activity were produced by alterations of the maximal number of specific binding sites.