Regulation of peripheral-type benzodiazepine receptors following repeated benzodiazepine administration.

The effects of chronic benzodiazepine (BZD) treatment on rat peripheral-type benzodiazepine receptors (PBR) were studied. Five days treatment with the PBR ligands RO 5-4864 or diazepam (DZ) up-regulates kidney PBR. In contrast clonazepam, a specific central-type BZD receptor ligand, did not alter 3H-RO 5-4864 binding. Fourteen days administration of DZ produced an up-regulation of kidney and heart PBR and a down-regulation of testicular PBR. The results suggest that chronic BZD exposure differentially regulates PBR in peripheral organs.