Peripheral-type benzodiazepine receptor: a protein of mitochondrial outer membranes utilizing porphyrins as endogenous ligands
The peripheral-type benzodiazepine receptor is a site identified by its nanomolar affinity for (/sup 3/H)diazepam, similar to the affinity of diazepam for the central-type benzodiazepine receptor in the brain. The peripheral type benzodiazepine receptor occurs in many peripheral tissues but has discrete localizations as indicated by autoradiographic studies showing uniquely high densities of the receptors in the adrenal cortex and in Leydig cells of the testes. Subcellular localization studies reveal a selective association of the receptors with the outer membrane of mitochondria. Photoaffinity labeling of the mitochondrial receptor with (/sup 3/H)flunitrazepam reveals two discrete labeled protein bands of 30 and 35 kDa, respectively. The 35-kDa band appears to be identical with the voltage-dependent anion channel protein porin. Fractionation of numerous peripheral tissues reveals a single principal endogenous ligand for the receptor, consisting of porphyrins, which display nanomolar affinity. Interactions of porphyrins with the mitochondrial receptor may clarify its physiological role and account for many pharmacological actions of benzodiazepines.
- Research Organization:
- Johns Hopkins Univ. School of Medicine, Baltimore, MD (USA)
- OSTI ID:
- 6974835
- Journal Information:
- Fed. Proc., Fed. Am. Soc. Exp. Biol.; (United States), Vol. 1:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
PORPHYRINS
BIOLOGICAL FUNCTIONS
RECEPTORS
LABELLING
TRANQUILIZERS
AUTORADIOGRAPHY
BRAIN
CELL MEMBRANES
LIGANDS
MITOCHONDRIA
TESTES
TRITIUM COMPOUNDS
BODY
CARBOXYLIC ACIDS
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM AGENTS
DRUGS
FUNCTIONS
GONADS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MALE GENITALS
MEMBRANE PROTEINS
MEMBRANES
NERVOUS SYSTEM
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANOIDS
ORGANS
PROTEINS
PSYCHOTROPIC DRUGS
550201* - Biochemistry- Tracer Techniques