Effect of lesions in the striatum. nucleus accumbens and medial raphe on phencyclidine-induced stereotyped behaviors and hyperactivity in rats

The effect of lesioning the striatum, nucleus accumbens and medial raphe on phencyclidine(PCP)-induced stereotyped behaviors and hyperactivity was investigated to determine the site or sites of actions of PCP in rats. Bilateral lesions of the striatum diminished or abolished all the parameters of PCP-induced stereotyped behaviors, including sniffing, backpedalling, turning and head weaving 7 days after the operation. The medial raphe lesion significantly reduced PCP-induced back pedalling and head weaving. Bilateral lesions of the ventral portion of the nucleus accumbens did not affect the PCP-induced stereotyped behaviors. On the contrary, none of the lesions altered the sensitivity to PCP-induced hyperactivity 7 days after the operation. These results that PCP-induced stereotyped behaviors may be mediated in the striatum and the medial raphe but not the nucleus accumbens. Furthermore, PCP-induced hyperactivity may not result from PCP effects on these discrete brain areas.