新生期注射辣椒素对大鼠痛阈的影响

给生后2～3d的大鼠皮下注射Capsaicin(50mg/kg)或等量的溶剂,待生长至第6个月,用钾离子透入法测甩尾反射阈值,并记录外周传入复合动作电位,以观察Aδ和c波的功能情况。经辣椒素处理后的动物痛阈比对照组明显增高,二者比较有高度显著性差异(P<0.001),而且处理组雄性动物的痛阈大于雌性组,两者有显著性差异(P<0.05)。处理组动物除表现痛阈增高外,还伴有外周传入c纤维功能的丧失,表现为传入纤维复合动作电位c波幅值的减少,辣椒素对Aδ纤维的作用在本实验动物处理组不明显。以上结果表明,新生期大鼠经辣椒素处理后,可引起痛阈的增高,而且处理组动物的痛阈还存在性别的差异,其意义值得进一步探讨。

INFLUENCE OF NEONATAL CAPSAICIN TREATMENT ON PAIN THRESHOLD OF RATS

The neonatal rats of day 2 or 3 of life were givencapsaicin 50 mg/kg or the same dose salinesubcutaneously. Six months after neonatal trestment thethreshold of tail flick reflex to potassium ion pene-trating was tested and peripheral aiferent compound ac-tion, potential recorded. Neonatal capsaicin treatment in-creased rat's threshold to noxious potassium stmuli ob-viously and the pain threshold for male rats was higherthan, for female rats, there was signifcant difference be-tween then (P<0.05). In addition to that c fiber com-pound action potential was diminished No change forAδ couid be discovered The results indicated that theneurophysiology effects of capsaicic were remarkably spe-cific for type c sensory fibers, produced degenerationand loss of the majority of the c fibers