Schulz R, Wüster M, Herz A
J Pharmacol Exp Ther. 1984 Jul;230(1):200-4.
The opioid receptor preference of dynorphin A fragments, particularly of dynorphin A-(1-8) (DYN 8), has been evaluated in the mouse vas deferens by means of cross-tolerance studies, by their sensitivity to naloxone antagonism and by the use of the irreversible narcotic antagonist beta-funaltrexamine. The tolerance studies revealed kappa receptor activity for the longer fragments and delta activity for the shorter fragments. DYN 8 displayed kappa as well as delta activity, whereas no interaction with mu receptors was observed. The naloxone sensitivity of dynorphin A and its fragments was low with the exception of DYN 8, that displayed an intermediate sensitivity. There was no indication that this intermediate value for DYN 8 was due to an interaction with mu receptors. This conclusion was strengthened in experiments using beta-funaltrexamine. The kappa and delta activity of DYN 8 does not explain the intermediate sensitivity to naloxone. It is proposed that DYN 8 may interact in the mouse vas deferens with a different opioid receptor than the classical mu, kappa- and delta-type.
通过交叉耐受性研究、对纳洛酮拮抗作用的敏感性以及使用不可逆麻醉拮抗剂β-氟奈曲胺，在小鼠输精管中评估了强啡肽A片段，特别是强啡肽A-(1-8)(DYN 8)的阿片受体偏好性。耐受性研究显示，较长片段具有κ受体活性，较短片段具有δ受体活性。DYN 8表现出κ和δ受体活性，而未观察到与μ受体的相互作用。除DYN 8表现出中等敏感性外，强啡肽A及其片段对纳洛酮的敏感性较低。没有迹象表明DYN 8的这种中等敏感性是由于与μ受体相互作用所致。在使用β-氟奈曲胺的实验中，这一结论得到了加强。DYN 8的κ和δ受体活性并不能解释其对纳洛酮的中等敏感性。有人提出，DYN 8在小鼠输精管中可能与不同于经典μ、κ和δ型的阿片受体相互作用。
