The Effect of Cumulative Dosing on the Analgesic Potency of Morphine in Mice

摘要: Opioid analgesic potency can be evaluated using cumulative dosing, in which subjects are repeatedly administered a drug and tested after each dose until criterion effect is reached. Although many laboratories use the effects of varying starting magnitude increment on morphine analgesia (tail flick) mice have not been evaluated. In experiment 1. were injected with same [0.5 mg/kg subcutaneously (SC)] 30 min later for analgesia. Mice that an (0.5, 1.0, 2.0, 2.5, or 3.0 mg/kg) retested. The process was continued all analgesic. There significant potency, relative increasing as increased. 2, different doses used constant 1.0 mg/kg. morphine, To determine if affect tolerance estimates, implanted SC 25- 75-mg placebo pellet 7 days then dose-response. Changes significantly affected degree 25-mg but pellet. did alter estimates tolerance. Overall, these data indicate impact morphine's determined by dosing protocols. Furthermore, parameters protocol. These results suggest procedures should standardized across experiments.