ASSESSMENT OF THE RELATIVE CONTRIBUTION OF PERIPHERAL AND CENTRAL COMPONENTS IN COCAINE PLACE CONDITIONING

A balanced place conditioning paradigm was used to assess the contribu tion of peripheral and central factors mediating place conditioning in duced by cocaine HCl. The first experiment was conducted to examine ch anges in locomotor activity and extracellular dopamine (DA) concentrat ions in the nucleus accumbens (NACC) following intraperitoneal (IP) in jections of cocaine HCl (15 mg/kg) or cocaine methiodide (19.6 mg/kg). IP cocaine HCl significantly increased locomotor activity and extrace llular NACC DA, whereas IP cocaine methiodide failed to increase eithe r locomotor activity or extracellular DA in the NACC. In the second ex periment, IP cocaine HCl (15 mg/kg) induced a significant conditioned place preference; however, neither IP procaine HCl (25 or 50 mg/kg) no r IP cocaine methiodide (4.9, 9.8, or 19.6 mg/kg) induced preferences for the drug-paired compartment. In the third experiment, intracerebro ventricular (ICV) infusions of cocaine HCl (25 mu g/2 mu l) or cocaine methiodide (1 or 5 mu g/2 mu l) induced significant place conditionin g for the drug-paired compartment. These results suggest place conditi oning induced by cocaine HCl is mediated centrally and that the local anesthetic properties alone do not contribute to this effect to any si gnificant degree.