奥曲肽对谷氨酸钠诱发的Aδ和C纤维放电活性的抑制效应

Inhibitory effect of octreotide on sodium glutamate-evoked activation of Aδ and C fibers

目的:探讨生长抑素激动剂奥曲肽是否通过抑制兴奋性神经递质谷氨酸的作用而产生抗伤害感受作用。方法:在DA大鼠脊神经背侧皮支分离细束,随机分为对照组、谷氨酸钠组、奥曲肽组和环生长抑素组。观察大鼠感受野注射谷氨酸钠、奥曲肽或环生长抑素预处理后Aδ和C纤维放电率。结果:与对照组比较,谷氨酸钠组大鼠Aδ及C纤维放电率明显升高(P<0.05);与谷氨酸钠组比较,奥曲肽组大鼠注射过程中以及注射后5min内Aδ和C纤维放电率明显降低(P<0.05);与谷氨酸钠组比较,环生长抑素组大鼠注射过程中以及注射后5min内平均放电率差异无统计学意义(P>0.05)。结论:外周生长抑素受体激动剂奥曲肽通过抑制谷氨酸钠诱导的外周Aδ和C纤维放电活性而抑制伤害感受器。

Objective To investigate whether octreotide,a somatostatin receptor agonist,plays antinociceptive effect by inhibiting the role of exciting neurotransmitter glutamate in periphery.Methods The nerve filaments on the dorsal cutaneous branches of spinal nerve of DA rats were dissected.The filaments were randomly divided into control group,sodium glutamate group,octreotide group,and cyclo-somatostatin group.The discharge rate of Aδand C fibers were observed after injected with sodium glutamata,octreotide,and cyclo-somatos tatin into the receptive field of rats.Results Compare with control group,the discharge rate of Aδand C fibers were increased significantly in sodium glutamate group（P〈0.05）.The discharge rate of Aδand C fibers of the rats in octreotide group were significantly decreased than those in sodium glutamate group during injection and 5 min after injection（P〈0.05）;however,there were no significant differences in the discharge rates of Aδand C fibers of the rats between cyclo-somatostatin group and sodium glutamate group during injection and 5 min after injection（P〈0.05）.Conclusion Octreotide,a somatostatin receptor agonist,inhibits the nociceptor by reducing glutamateevoked activation of Aδand C fibers.