Zhang Qiang, Gallo Robert V
Department of Physiology and Neurobiology, University of Connecticut, Storrs 06269-4156, USA.
Endocrine. 2002 Jun;18(1):27-32. doi: 10.1385/ENDO:18:1:27.
The objective of this study was to determine whether prodynorphin-derived opioid peptides could block the spontaneous luteinizing hormone (LH) surge and ovulation, and if so, whether this inhibitory action was mediated through kappa-opioid receptors. Various doses of dynorphin peptides (dynorphin A(1-17), dynorphin A(1-8), dynorphin B, alpha- and beta-neoendorphin) were infused into the brain through third-ventricle cannulae in rats between 1330-1800 h on proestrus. Each dynorphin peptide blocked the LH surge and ovulation in a dose-dependent manner. Dynorphin A(1-17) and A(1-8) were equally effective in producing these actions, and more potent than either dynorphin B or alpha- or beta-neoendorphin. U50,488H, a specific kappa-opioid receptor agonist, also blocked the LH surge and ovulation. When a mixture of five dynorphin peptides was infused intraventricularly, each at a dose that inhibited the LH surge, both the surge and ovulation were blocked. However, when norbinaltorphimine, a specific kappa-opioid receptor antagonist, was coinfused with the mixture of dynorphin peptides, the LH surge and ovulation were fully restored. These results demonstrate that prodynorphin-derived opioid peptides, acting through kappa-opioid receptors, can block the LH surge and ovulation. Dynorphin A(1-17) and A(1-8) are the most potent in this regard.
本研究的目的是确定强啡肽原衍生的阿片肽是否能阻断促黄体生成素（LH）的自发峰和排卵，如果可以，这种抑制作用是否通过κ-阿片受体介导。在动情前期的1330 - 1800 h之间，通过第三脑室插管将不同剂量的强啡肽肽（强啡肽A(1 - 17)、强啡肽A(1 - 8)、强啡肽B、α-和β-新内啡肽）注入大鼠脑内。每种强啡肽肽均以剂量依赖性方式阻断LH峰和排卵。强啡肽A(1 - 17)和A(1 - 8)在产生这些作用方面同样有效，且比强啡肽B或α-或β-新内啡肽更有效。特异性κ-阿片受体激动剂U50,488H也能阻断LH峰和排卵。当脑室内注入五种强啡肽肽的混合物，每种肽的剂量均能抑制LH峰时，LH峰和排卵均被阻断。然而，当特异性κ-阿片受体拮抗剂norbinaltorphimine与强啡肽肽混合物共同注入时，LH峰和排卵完全恢复。这些结果表明，强啡肽原衍生的阿片肽通过κ-阿片受体发挥作用，可阻断LH峰和排卵。在这方面，强啡肽A(1 - 17)和A(1 - 8)最为有效。
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