Grisel J E, Wiertelak E P, Watkins L R, Maier S F
Department of Psychology-Behavioral Neurosciences, University of Colorado, Boulder 80309.
Pharmacol Biochem Behav. 1994 Dec;49(4):1029-35. doi: 10.1016/0091-3057(94)90260-7.
The present experiments investigated the effects of route of drug injection on two of the phenomena associated with repeated, cued, morphine administration. Experiment 1 examined the degree of situational specificity of analgesic tolerance following 5 days of morphine (5 mg/kg) delivered either subcutaneously (SC) or intravenously (i.v.). Situationally specific tolerance was only observed following i.v. morphine, although nonspecific tolerance was evident in both instances. Experiment 2 indicated that this difference was not due to dose, as neither 2.5 or 7.5 mg/kg SC morphine produced demonstrable situationally specific tolerance. Experiment 3 examined the putative existence of compensatory responses underlying the observed tolerance. Hyperalgesia in response to the environment in which morphine was experienced was evident in animals trained with i.v. morphine, but not in those receiving repeated SC injections. Potential explanations for these effects of route of administration are discussed.
本实验研究了药物注射途径对与重复、提示性吗啡给药相关的两种现象的影响。实验1检测了皮下注射（SC）或静脉注射（i.v.）5天吗啡（5mg/kg）后镇痛耐受性的情境特异性程度。仅在静脉注射吗啡后观察到情境特异性耐受性，尽管在两种情况下非特异性耐受性均很明显。实验2表明这种差异不是由于剂量所致，因为2.5或7.5mg/kg皮下注射吗啡均未产生明显的情境特异性耐受性。实验3检测了所观察到的耐受性背后潜在的代偿反应的存在情况。在接受静脉注射吗啡训练的动物中，对曾使用吗啡的环境产生的痛觉过敏很明显，但在接受重复皮下注射的动物中则不明显。讨论了给药途径产生这些效应的潜在解释。
