Identification of the binding subunit of the sigma-type opiate receptor by photoaffinity labeling with 1-(4-azido-2-methyl(6-/sup 3/H)phenyl)-3-(2-methyl(4,6-/sup 3/H)phenyl)guanidine
The sigma-type opiate receptor is a distinct binding site in the brain that may mediate some of the psychotomimetic effects caused by benzomorphan opiates and phencyclidine in humans. The authors have developed a synthetic, highly selective ligand for this receptor, 1,3-di-o-tolylguanidine (DTG). To identify the binding protein(s) of the sigma receptor, they have now synthesized a radiolabeled azide derivative of DTG, ((/sup 3/H)N/sub 3/DTG). In guinea pig brain membrane binding assays conducted in the dark, (/sup 3/H)N/sub 3/DTG bound reversibly, selectively, and with high affinity to sigma receptors. The drug specificity profile of reversible (/sup 3/H)-N/sub 3/DTG binding was identical to that of (/sup 3/H)DTG and /sup 3/H-labeled (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine binding indicating that (/sup 3/H)N/sub 3/DTG is a selective sigma receptor ligand. Guinea pig brain membranes were photoaffinity-labeled with (/sup 3/H)N/sub 3/DTG. NaDodSO/sub 4//PAGE of detergent-solubilized membrane extract identified a single 29-kDa radioactive band. Sepharose Cl-6B gel chromatography of photolabeled brain membranes solubilized with the nondenaturing detergent sodium cholate showed a radioactive complex with a Stoke's radius of 4.6 nm (M/sub r/, 150,000) that may represent the intact sigma receptor complex. NaDodSO/sub 4//PAGE of this complex showed the radiolabeled material was a 29-kDa polypeptide that may be binding subunit of the sigma receptor.
- Research Organization:
- Oregon Health Sciences Univ., Portland (USA)
- OSTI ID:
- 6143401
- Journal Information:
- Proc. Natl. Acad. Sci. U.S.A.; (United States), Journal Name: Proc. Natl. Acad. Sci. U.S.A.; (United States) Vol. 85:8; ISSN PNASA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
59 BASIC BIOLOGICAL SCIENCES
ANIMALS
AUTORADIOGRAPHY
BIOCHEMICAL REACTION KINETICS
BODY
BRAIN
CELL CONSTITUENTS
CELL MEMBRANES
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CHEMICAL REACTIONS
CROSS-LINKING
DERIVATIZATION
DOSE-RESPONSE RELATIONSHIPS
DRUGS
GUINEA PIGS
KINETICS
LABELLED COMPOUNDS
LIGANDS
MAMMALS
MEMBRANE PROTEINS
MEMBRANES
MOLECULAR STRUCTURE
NARCOTICS
NERVOUS SYSTEM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
POLYMERIZATION
POLYPEPTIDES
PROTEINS
REACTION KINETICS
RECEPTORS
RODENTS
TRITIUM COMPOUNDS
VERTEBRATES