GUINEA-PIG VAS-DEFERENS CONTAINS SIGMA BUT NOT PHENCYCLIDINE RECEPTORS

Homogenates from guinea pig vas deferens were examined for possible existence of ρ receptor and phencyclidine (PCP) receptor using a radioligand binding assay. [3H](+)-SKF-10047 bound saturably in the homogenates to a single population of binding sites with a Kd of 311 nM and a Bmax of 1090 fmol/mg protein. IC50s of several representative ρ drugs in displacing [3H](+)-SKF-10047 from this binding site were very much similar to the IC50s of those drugs in the brain ρ receptor binding assay. A correlation coefficient of 0.96 was obtained when IC50s from vas deferens were compared with those from the brain assay. Attempts to demonstrate PCP receptors in this tissue using [3H]TCP (N-[1-(2-thienyl)cyclohexyl]piperidine), however, yielded negative results. The results indicate that while guinea pig vas deferens contains ρ receptors, PCP receptors may be absent in this tissue. © 1990.