In vivo pharmacological resultant analysis reveals noncompetitive interactions between opioid antagonists in the rat tail-withdrawal assay.

摘要: Background and purpose: Pharmacological resultant analysis is a technique that can detect secondary effects of competitive antagonists in vitro. The utility pharmacological as potential tool for the investigation antagonist interactions vivo was examined present study using two opioid antagonists, naltrexone CTAP. Experimental approach: Using experimental design analysis, well-characterized presence multiple doses CTAP to block antinociceptive morphine rat warm-water (55oC), tail-withdrawal assay. Key results: Alone, all naltrexone, CTAP, CTOP blocked morphine. In fixed 1 or 10 μg increasing produced dose-dependent shifts right dose-response curve. However, lower dose combination with failed alter 0.1 mg kg−1 irregular curves. Conclusions implications: Resultant applied an apparent pKC value found be one log unit higher than pA2 evidence may have actions signal transducer function altered by combinations these antagonists. Taken together, data suggest reveal novel between vivo. British Journal Pharmacology (2006) 149, 1071–1082. doi:10.1038/sj.bjp.0706946