Effects of repeated phencyclidine treatment on serotonin transporter in rat brain.
Neuroscience letters February 11, 2000 T Hori, S Abe, A Baba et al.
Repeated treatment with phencyclidine (PCP) over 14 days at 7.5 mg/kg per day significantly reduced the frequency of backpedalling, a serotonergic stereotyped behavior, indicating tolerance. This repeated treatment also decreased the equilibrium dissociation constant (Kd) of [3H]paroxetine binding to serotonin transporters in whole brain excluding the cerebellum, without changing the maximum number of binding sites (Bmax). A single PCP treatment did not alter binding parameters. The results suggest that repeated PCP treatment induces tolerance in serotonergic stereotyped behavior and increases the affinity of serotonin transporters, possibly as a compensatory response to chronic inhibition of serotonin uptake.