Guinea pig vas deferens contains sigma but not phencyclidine receptors

Homogenates from guinea pig vas deferens were examined for possible existence of sigma 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 and a Bmax of 1090 fmol/mg protein. IC50S of several representative sigma in displacing [3H](+)-SKF-10047 from this binding site were very much similar to the IC50S of those drugs in the brain sigma 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 sigma receptors, PCP receptors may be absent in this tissue.