Behavioral effects of phencyclidine and some of its metabolites in developing cats

Chronic treatment with low doses (1-2 mg/kg) of phencyclidine (PCP) produces marked behavioral effects in the developing kitten. These effects are age-dependent. Under 21 days the major response consists of rostrocaudal forelimb movements. After this age the major responses are ataxic locomotion and waxy rigidity. In the present experiment the behavioral effect of subcutaneous injections of higher doses of PCP, two of its metabolites, phencylclohexylamine (PCA) and an alcohol (N-(5-hydroxypentyl)-1-phenycyclohexylamine) (AL) and one PCP analog (N-N-diethylaminophenylhexylamine (NND] were tested in kittens between 30-50 days of age. The behavior of the kittens was assessed from 10-15 min pre-injection to up to 5 hr postinjection and at 24 hr postinjection. The most intense responses were produced by PCP and NND and consisted of waxy rigidity (limbs in abnormal postures for extended time periods) with the animal completely immobile. PCA was less effective, producing only tremor and staggering followed by loss of hindlimb support. AL was the least effective producing minimal behavioral responses. These results indicate that some of the metabolites of PCP, while active, are not as potent as PCP itself. Subsequent testing indicated that behavioral tolerance to the effects of PCP, NND and PCA occurred after a single administration of these compounds.