奥曲肽抑制辣椒素激活大鼠皮肤感觉神经纤维 C 和 Aδ纤维。

Octreotide inhibits capsaicin-induced activation of C and Aδ afferent fibres in rat hairy skin in vivo.

Department of Physiology and Pathophysiology, Xi'an Jiaotong University School of Medicine, Shaanxi, China.

Clin Exp Pharmacol Physiol. 2011 Aug;38(8):521-7. doi: 10.1111/j.1440-1681.2011.05542.x.

Abstract

The present study investigated whether the somatostatin receptor (SSTR) agonist, octreotide, could inhibit the activation of dorsal skin afferent fibres induced by local injection of capsaicin in the rat. 2. Single unit activity from Aδ mechano-heat sensitive (AMH; n = 41) and C mechano-heat sensitive (CMH; n = 30) afferents was recorded after their isolation in thin filaments from the dorsal cutaneous nerve branches. The effect of subcutaneous octreotide injection on the change in discharge rate and mechanical threshold induced by capsaicin was determined. 3. Capsaicin (0.05%) injection into the edge of the receptive field of both AMH and CMH units increased their discharge rate and decreased their mechanical threshold. Pre-injection of octreotide inhibited these responses, and co-application of SSTR antagonist, cyclosomatostatin, reversed the inhibitory effect of octreotide. 4. The present study provides electrophysiological evidence that the signal evoked by the somatostatin receptor inhibits the activation and mechanical sensitization evoked by capsaicin in the terminals in small-diameter sensory neurons.

摘要

本研究旨在探讨生长抑素受体（SSTR）激动剂奥曲肽是否能抑制辣椒素局部注射引起的大鼠背皮传入纤维的激活。
在从背皮神经分支的细纤维中分离出 Aδ机械热敏感（AMH；n = 41）和 C 机械热敏感（CMH；n = 30）传入纤维后，记录其单个单位的活动。确定皮下奥曲肽注射对辣椒素引起的放电率和机械阈值变化的影响。
辣椒素（0.05%）注射到 AMH 和 CMH 单位的感受野边缘增加了它们的放电率并降低了它们的机械阈值。奥曲肽预先注射抑制了这些反应，而 SSTR 拮抗剂环缩素的共同应用逆转了奥曲肽的抑制作用。
本研究提供了电生理学证据，表明生长抑素受体信号抑制了小直径感觉神经元末端由辣椒素引起的激活和机械敏化。