Woolf C J, Fitzgerald M
Neurosci Lett. 1982 Mar 17;29(1):67-72. doi: 10.1016/0304-3940(82)90366-4.
A presynaptic inhibitory role for opioid peptides in the control of C-fibre-evoked activity in the dorsal horn has been investigated. The excitability of C-fibre terminals in the dorsal horn of decerebrate spinal rats was tested using intraspinal terminal stimulation and recording the size of the antidromic C wave from the dorsal roots. Naloxone (1-2 mg/kg) failed to alter the baseline terminal excitability of the C-fibres, but reduced the increase in terminal excitability produced by A-fibre afferent conditioning stimuli. The inhibition of postsynaptic C-evoked activity in lamina 5 cells produced by A-afferent fibre conditioning stimuli was also reduced by naloxone. This effect may reflect the reversal of an opioid-mediated presynaptic inhibition, although blockade of a direct postsynaptic inhibitory action could also be involved.
已对阿片肽在控制背角C纤维诱发活动中的突触前抑制作用进行了研究。采用脊髓内终末刺激并记录背根逆向C波的大小，测试了去大脑脊髓大鼠背角C纤维终末的兴奋性。纳洛酮（1 - 2毫克/千克）未能改变C纤维终末的基线兴奋性，但减少了A纤维传入条件刺激所产生的终末兴奋性增加。纳洛酮也降低了A传入纤维条件刺激对第5层细胞中突触后C诱发活动的抑制作用。这种效应可能反映了阿片类药物介导的突触前抑制的逆转，尽管也可能涉及直接突触后抑制作用的阻断。
