Abstract
The use of ?9-THC hemisuccinate (HS) in a suppository formulation is an attempt to develop a cannabinoid possessing possible therapeutic effects with a minimal side effect profile. The purpose of this study was to investigate the antinociceptive and reinforcing effects of rectally administered ?9-THC-HS in rats. Tests were conducted in two groups of animals: Complete Freund's adjuvant-inflamed animals (CFA) and non-inflamed controls. A hotplate test was administered to index hyperalgesia and possible analgesic effects of ?9-THC-HS on thermal nociception. CFA animals demonstrated shorter latencies than non-inflamed animals. The highest dose of ?9-THC-HS produced longer hotplate latencies. Additionally, the reinforcing properties of ?9-THC-HS were evaluated using the Conditioned Place Preference (CPP) paradigm. ?9-THC-HS produced an increase in preference scores in non-inflamed animals (positive reinforcement), but did not affect preference scores in CFA animals. These data suggest that ?9-THC-HS has therapeutic potential and is unlikely to possess an abuse liability when used in the context of chronic pain.