Bell J A
Neuroscience Branch, National Institute on Drug Abuse, Baltimore, MD 21224.
Eur J Pharmacol. 1989 Sep 1;168(1):101-5. doi: 10.1016/0014-2999(89)90639-0.
The effects of chronic morphine on endogenous opioid function were examined in feline spinal cord. Naloxone-induced facilitation (disinhibition) of the C-fiber reflex was used as a model to reflect endogenous opioid function. Facilitation was reduced 24 h after withdrawal of chronic morphine (14 days). Acute morphine failed to depress C-fiber reflexes in the abstinent cats, indicating tolerance. Thus, these results demonstrated that, after chronic morphine, spinal endogenous opioid function was reduced due to tolerance.
在猫的脊髓中研究了慢性吗啡对内源性阿片类物质功能的影响。使用纳洛酮诱导的C纤维反射易化（去抑制）作为反映内源性阿片类物质功能的模型。在停用慢性吗啡（14天）后24小时，易化作用减弱。急性吗啡未能抑制戒断猫的C纤维反射，表明出现了耐受性。因此，这些结果表明，慢性吗啡作用后，脊髓内源性阿片类物质功能因耐受性而降低。
