Effects of phencyclidine on prepulse inhibition of acoustic startle response in the macaque.

RATIONALE

Prepulse inhibition (PPI) of the acoustic startle response (ASR) provides an index of neurophysiological dysfunction in schizophrenia and a method for analyzing underlying neurochemical mechanisms. In rodents, phencyclidine (PCP) and other N-methyl-D-aspartate receptor (NMDAR) antagonists induce schizophrenia-like PPI deficits. Similar effects have recently been observed in a New World monkey species, Cebus apella.

OBJECTIVES

The present study evaluates the degree to which similar effects are observed in an Old World monkey, M. fascicularis.

METHODS

An initial study evaluated effects of interstimulus interval on PPI amplitude and latency. A subsequent study evaluated effects of PCP (0.25 mg/kg i.m.) on PPI of the ASR.

RESULTS

Prepulses reduced both the amplitude and latency of the ASR. PCP treatment prevented both effects without affecting amplitude or latency of the ASR itself.

CONCLUSIONS

These results demonstrate that both amplitude reduction and latency facilitation are observed during PPI in the monkey and are disrupted by PCP.