Date of Award

6-2012

Degree Name

Master of Arts

Department

Psychology

First Advisor

Dr. Lisa E. Baker

Second Advisor

Dr. Alan D. Poling

Third Advisor

Dr. Cynthia J. Pietras

Keywords

Salvinorin A, kappa-receptor, morphine, reward, place-conditioning

Access Setting

Masters Thesis-Open Access

Abstract

Salvinorin A (SA), a selective kappa opioid receptor agonist, is the main psychoactive ingredient in the plant Salvia divinorum. The addiction potential of this naturally occurring hallucinogen is currently under investigation using well-validated preclinical screening procedures, including conditioned place preference (CPP). The primary aim of the current study was to determine the effects of SA on CPP established by morphine in adult rats. A secondary aim was to determine if the vehicle used to dissolve SA, dimethylsulfoxide (DMSO), influenced the outcome of SA place conditioning. Rats were randomly assigned to one of four treatment groups: morphine (10 mg/kg) vs. saline; SA (0.4 mg/kg) + morphine (10 mg/kg) vs. DMSO + saline; DMSO vs. saline; SA (0.4 mg/kg) vs. DMSO. Rats were exposed to a 15-min habituation session for three consecutive days. Daily 30-min place conditioning trials were conducted over the next eight days followed by a test day. Morphine initially suppressed locomotor activity but activity increased with repeated exposure to morphine, whereas the combination of SA and morphine reduced morphine-induced locomotor activity. However, SA did not attenuate morphine-induced CPP. In a second experiment, CPP trials were conducted with SA prepared in either a DMSO-water (3:1) solution or in an ethanol/TWEEN80 /water (1:1:8) solution. Regardless of the vehicle used, results of experiment 2 indicated that SA failed to establish CPP and produced modest aversive effects.

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