Davis M E, Akera T, Brody T M
J Pharmacol Exp Ther. 1979 Oct;211(1):112-9.
Previous studies revealed that the characteristics of opiate binding sites are different in brainstem slices and homogenates. In the present study, the binding of opiate agonists, morphine and etorphine, and that of the antagonist, naloxone, to thin slices of rat brain stem was studied. Sodium ion inhibits agonist binding and enhances antagonist binding in brainstem slices. Development of the analgesic tolerance to morphine is accompanied by a reduction of opiate binding. The opiate binding recovers partially toward control values during morphine withdrawal. Kinetic analyses indicate that sodium-induced changes in opiate binding sites are different from those caused by chronic morphine treatment. These results provide evidence that analgesic tolerance is associated with changes in opiate receptors.
先前的研究表明，阿片类结合位点在脑干切片和匀浆中的特性有所不同。在本研究中，对阿片类激动剂吗啡和埃托啡以及拮抗剂纳洛酮与大鼠脑干薄片的结合进行了研究。钠离子在脑干切片中抑制激动剂结合并增强拮抗剂结合。对吗啡镇痛耐受性的发展伴随着阿片类结合的减少。在吗啡戒断期间，阿片类结合部分恢复至对照值。动力学分析表明，钠离子引起的阿片类结合位点变化与慢性吗啡治疗引起的变化不同。这些结果提供了证据，表明镇痛耐受性与阿片受体的变化有关。
