Jones L S, Grooms S Y, Salvadori S, Lazarus L H
Department of Developmental Biology and Anatomy, University of South Carolina School of Medicine, Columbia 29208.
Eur J Pharmacol. 1994 Oct 13;264(1):39-48. doi: 10.1016/0014-2999(94)90633-5.
Dermorphin, a specific mu 1-opioid receptor agonist, has been studied for its effects on the physiology of the rat hippocampal slice. Population responses in CA3 to threshold levels of stimulation from both the Schaffer collaterals and mossy fibers were markedly enhanced in the presence of 50-100 nM dermorphin, while CA1 responses to threshold Schaffer collateral stimulation were less effected. Responses at higher stimulus levels than threshold were negligibly responsive to dermorphin, although at 500 nM dermorphin all responses became epileptiform and in some slices spontaneous bursting erupted. [L-Ala2]Dermorphin, a biologically inactive dermorphin analogue, did not increase response amplitudes nor evoke epilepsy in the slice. 5 microM naloxone blocked the effect of dermorphin on Schaffer collateral and mossy fiber-evoked responses, though less effectively in the latter case. These data provide in vitro evidence to support in vivo observations that excessive mu-opioid receptor activation can be proconvulsant in the hippocampus, but that normally the receptors may function as facilitatory modulators of responses in the threshold range.
强啡肽是一种特定的μ1阿片受体激动剂，已对其在大鼠海马切片生理学方面的作用进行了研究。在存在50 - 100 nM强啡肽的情况下，CA3对来自Schaffer侧支和苔藓纤维的阈刺激水平的群体反应显著增强，而CA1对阈Schaffer侧支刺激的反应受影响较小。高于阈刺激水平的反应对强啡肽的反应可忽略不计，尽管在500 nM强啡肽时所有反应都变成癫痫样，并且在一些切片中出现自发爆发。[L - Ala2]强啡肽是一种无生物活性的强啡肽类似物，在切片中既不增加反应幅度也不诱发癫痫。5 μM纳洛酮阻断了强啡肽对Schaffer侧支和苔藓纤维诱发反应的作用，尽管在后一种情况下效果较差。这些数据提供了体外证据来支持体内观察结果，即过量的μ阿片受体激活在海马中可能具有惊厥作用，但通常这些受体可能作为阈范围内反应的易化性调节剂发挥作用。
