Phencyclidine ("angel dust") analogs and sigma opiate benzomorphans cause cerebral arterial spasm.

Abstract

Several psychotomimetic phencyclidine (PCP) analogs, N-ethyl-1-phenylcyclohexylamine (PCE), N-[1-(2-thienyl)cyclohexyl]piperidine (TCP), N-[1-(thienyl)cyclohexyl]pyrrolidine (THP), ketamine and N,N-dimethyl-1-phenylcyclohexylamine (PCDEA), were tested on basilar and middle cerebral arteries of the dog in vitro and induced contraction in these blood vessels with a maximal contractile activity (i.e., intrinsic activity) similar to that of PCP. The concentration-effect curves of these compounds were parallel to the curve of PCP (P < 0.01). The relative potency was PCE > TCP > PCP > THP > PCDEA > ketamine. A PCP analog with no psychotomimetic activity, 1-piperidinocyclohexanecarbonitrile (PCC), did not not induce the blood vessels to contract, nor did the opiate morphine. Three psychotomimetic benzomorphans (pentazocine, cyclazocine and N-allylnorcyclazocine) also produced contraction, and had concentration-effect curves parallel to the curve of PCP, but with reduced intrinsic activities (i.e., maximal tensions were lowered) compared to PCP. A .kappa. opiate, ethylketocyclazocine, relaxed the blood vessels in a dose-dependent manner. Evidently there is a distinct PCP receptor on cerebral blood vessels and certain benzomorphans may produce cerebral vasospasm via PCP-receptor interactions.