Valentino R J, Bostock E, Dingledine R
Life Sci. 1982;31(20-21):2339-42. doi: 10.1016/0024-3205(82)90151-5.
The ability of several opioids in potentiating the synaptic activation of CA1 pyramidal cells in the rat hippocampal slice were compared. Morphine and the opioid peptides, (D-ala2, D-leu5)-enkephalin (DADL), morphiceptin, beta-endorphin, and Tyr-D-Ser-Gly-Phe-Leu-Thr (DSThr) caused a concentration-dependent, naloxone-reversible shift to the left in the input-output (IO) curve constructed by plotting the population spike as a function of the field EPSP. These opioids then produced an increase in the size of the population spike while leaving the EPSP unaffected. In contrast, the kappa agonist prototype, ethylketazocine, had no effect on the IO curve when perfused in concentrations up to 10 microM. The rank order of potency for the opioids in the CA1 region of the hippocampus was DADL greater than DSThr greater than beta-endorphin greater than morphiceptin greater than morphine much greater than ethylketazocine. Thus, opioids that are more specific for delta opiate receptors were the most potent and mu receptor agonists, the least potent in this action. Taken together with previous studies suggesting that morphine and DADL may interact with a common opiate receptor in the CA1 region, the results are consistent with the notion that these epileptiform effects may be primarily mediated by delta opiate receptors in this area although the potency of morphiceptin indicates that mu receptors play some role in this effect.
比较了几种阿片类药物增强大鼠海马脑片CA1锥体细胞突触激活的能力。吗啡和阿片肽，（D-丙氨酸2，D-亮氨酸5）-脑啡肽（DADL）、吗啡肽、β-内啡肽和酪氨酰-D-丝氨酰-甘氨酰-苯丙氨酰-亮氨酰-苏氨酸（DSThr）导致输入-输出（IO）曲线浓度依赖性、纳洛酮可逆性左移，该曲线通过绘制群体峰电位作为场兴奋性突触后电位（fEPSP）的函数构建。这些阿片类药物随后使群体峰电位大小增加，而fEPSP不受影响。相比之下，κ激动剂原型乙基酮唑辛在灌注浓度高达10μM时对IO曲线没有影响。在海马CA1区，阿片类药物的效价顺序为DADL＞DSThr＞β-内啡肽＞吗啡肽＞吗啡＞＞乙基酮唑辛。因此，对δ阿片受体更具特异性的阿片类药物效力最强，而μ受体激动剂在该作用中效力最弱。结合先前的研究表明吗啡和DADL可能在CA1区与共同的阿片受体相互作用，结果与以下观点一致，即这些癫痫样效应可能主要由该区域的δ阿片受体介导，尽管吗啡肽的效力表明μ受体在该效应中也起一定作用。
