Subchronically applied phencyclidine fails to disrupt prepulse inhibition in rats

To simulate psychosis in rats, the psychotomimetic agent phencyclidine (PCP , 5.0 mg/kg) was administered either by daily pulsatile injections or by co ntinuous delivery with subcutaneously implanted, PCP-loaded controlled rele ase polymers for a 5 day period. The acoustic startle response (ASR) and th e prepulse inhibition (PPI) were then assessed 15 and 60 min as well as 24 h after the PCP application was discontinued. An impaired PPI occurred only under the acute influence of the last PCP injection, i.e. 15 and 60 min af ter last PCP treatment when it had previously been given in a pulsatile man ner but not when it was administered continuously. The ASR to unpaired stim uli after PCP was not modified. These findings suggest that disruption of P PI occurs only under the acute influence of PCP and that PPI deficits are n ot primarily the consequence of structural brain damage which PCP produces. (C) 1999 Elsevier Science B.V. All rights reserved.