DIFFERENTIAL-EFFECTS OF REPEATED DL-PENTAZOCINE TREATMENT ON SIGMA-BINDING SITES IN DISCRETE BRAIN-AREAS OF THE RAT

Repeated treatment with dl-pentazocine (5-10 mg/kg i.p.), but not d-me thamphetamine (4.8 mg/kg i.p.), twice daily for 8 days diminished the specific [H-3]1,3-di-o-tolylguanidine (DTG) binding to the haloperidol -sensitive sigma sites in rat striatum and hippocampus. Either drug fa iled to cause any changes in the binding to the hypothalamus and prefr ontal cortex. The pentazocine-induced diminution in the striatum was a ccompanied by a decrease in the density with an increase in the affini ty of the [H-3]DTG binding. These data suggest that repetitive use of dl-pentazocine may influence the regulation systems of the a site in s pecific brain regions.