Characterization of specific binding sites for (/sup 3/H)(d)-N-allylnormetazocine in rat brain membranes

Journal Article · Tue Jan 01 00:00:00 EST 1985 · Mol. Pharmacol.; (United States)

OSTI ID:5666181

Itzhak, Y; Hiller, J M; Simon, E J

Binding of (/sup 3/H)(d)-N-allylnormetazocine ((/sup 3/H)(d)-NANM) to rat brain membranes is stereospecific, reversible, and saturable (Bmax . 260 fmol/mg of protein) and manifests moderately high affinity (Kd . 20 nM). The rank order of potency among opioidbenzomorphans and phencyclidine (PCP) analogs for competition for (/sup 3/H)(d)-NANM-binding sites is as follows: (d)-NANM . PCP-3-OH greater than (d)-cyclazocine greater than N-ethylphenylcyclohexylamine greater than PCP greater than (l)-cyclazocine . dextrorphan greater than (d/l)-ethylketocyclazocine greater than (d/l)-bremazocine greater than (1)-NANM greater than 1-phenylcyclohexylamine greater than levorphanol. Other opioid ligands, relatively selective for each of the types of opioid binding sites other than sigma, such as morphine (mu), H-Tyr-D-Ala(Me)Phe-NH-CH2-OH (mu), D-Ala2-D-Leu5-enkephalin (delta), tifluadom (kappa), and U 50488 (kappa) as well as etorphine and naloxone were all unable to compete with (/sup 3/H)(d)-NANM for specific binding even at a concentration of 1 microM. Regional distribution studies of (/sup 3/H)(d)-NANM-binding sites show high density in the hippocampus, thalamus, hypothalamus, and amygdala and low density in cerebellum and nonfrontal neocortex membranes of the rat brain. These binding sites are very sensitive to protein-modifying enzymes and reagents such as trypsin and N-ethylmaleimide and to heat denaturation. These results provide direct biochemical evidence for the existence of distinct (d)-NANM-binding sites in rat brain.

• Research Organization: New York Univ. Medical Center, NY
• OSTI ID: 5666181
• Journal Information: Mol. Pharmacol.; (United States), Vol. 27:1
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CENTRAL NERVOUS SYSTEM DEPRESSANTS
CHEMICAL BONDS
AFFINITY
BIOCHEMISTRY
BRAIN
CELL MEMBRANES
COMPARATIVE EVALUATIONS
DENSITY
ENKEPHALINS
HIPPOCAMPUS
HYPOTHALAMUS
LIGANDS
MORPHINE
RATS
THALAMUS
TISSUE DISTRIBUTION
TRACER TECHNIQUES
TRITIUM COMPOUNDS
ALKALOIDS
ANALGESICS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BODY
CELL CONSTITUENTS
CENTRAL NERVOUS SYSTEM
CHEMISTRY
DISTRIBUTION
DRUGS
ENDORPHINS
ISOTOPE APPLICATIONS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
NARCOTICS
NERVOUS SYSTEM
NEUROREGULATORS
OPIUM
ORGANIC COMPOUNDS
ORGANS
PEPTIDES
PHYSICAL PROPERTIES
POLYPEPTIDES
PROTEINS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques