[3H]-(+)-pentazocine binding to sigma recognition sites in human cerebellum.
The binding characteristics of the sigma-1 selective benzomorphan [3H]-(+)-pentazocine were determined in human cerebellar membranes. Saturation binding analysis revealed two affinity sites with a KDH of 1.4 +/- 0.7 nM and a KDL of 33.6 +/- 11.9 nM. Kinetic studies performed at 25 degrees C demonstrated reversible binding with association and dissociation rate constants determined for two classes of sites. In saturation binding studies, the addition of (+)-SKF 10,047 occluded binding of [3H]-(+)-pentazocine to high affinity sigma binding sites. The affinity profile of ligands displacing [3H]-(+)-pentazocine was consistent with the labeling of sigma-1 recognition sites with haloperidol > (+)-pentazocine > (+)-SKF 10,047 > (+)-3-PPP > DTG > (-)-pentazocine > (-)-SKF 10,047. The potency of the putative D3 receptor-selective ligand (+)-7-OH-DPAT was close to that measured for (+)-pentazocine in displacement experiments. These data suggest that [3H]-(+)-pentazocine labels sigma-1 sites in human cerebellum under appropriate assay conditions.
Zabetian
C P
CP
Department of Neurology, University of Miami School of Medicine, Florida 33136.
Staley
J K
JK
Flynn
D D
DD
Mash
D C
DC
D001665:Binding Sites; D002531:Cerebellum / Q000378:metabolism*; D006801:Humans; D007700:Kinetics; D010423:Pentazocine / Q000378:metabolism*; D017480:Receptors, sigma / Q000378:metabolism*; D014316:Tritium
D017480:Receptors, sigma; D014316:Tritium; D010423:Pentazocine