Schulz R, Wüster M
Eur J Pharmacol. 1981 Nov 19;76(1):61-6. doi: 10.1016/0014-2999(81)90009-1.
The hypothesis of heterogeneity of opiate receptors was tested with the electrically stimulated mouse vas deferens. The experimental approach was based on the phenomenon of tolerance development of selective opiate receptors. It was found that opioids classified as mu-receptor agonists, e.g. sufentanyl and normorphine, do not necessarily exhibit cross-tolerance to each other. The same holds true for a variety of presumed kappa-receptor agonists. On the other hand, the delta-receptor agonists under investigation displayed complete cross-tolerance. These findings give rise to an interpretation which may postulate the existence of subtypes (isoreceptors) of the already known opiate receptors.
利用电刺激的小鼠输精管对阿片受体异质性假说进行了检验。实验方法基于选择性阿片受体耐受性发展现象。研究发现，归类为μ受体激动剂的阿片类药物，如舒芬太尼和去甲吗啡，不一定对彼此表现出交叉耐受性。各种假定的κ受体激动剂也是如此。另一方面，所研究的δ受体激动剂表现出完全交叉耐受性。这些发现引发了一种解释，该解释可能假定已知阿片受体存在亚型（同种受体）。
