金丝桃甙镇痛作用的机制

用小鼠光热辐射甩尾模型证明,低钙和高钙分别能增强和拮抗Hyp的镇痛作用。在痛介质诱发传入神经放电的模型上,同样证明低钙或高钙能显著加强或拮抗Hyp对组胺和氯化钾诱发神经放电的抑制作用。促进Ca²⁺内流的A₂₃₁₈₇几乎完全拮抗Hyp的末梢镇痛作用,并且在蛙坐骨神经标本上,Hyp可抑制KCl诱发的Ca²⁺内流。提示Hyp的镇痛作用与减少感觉神经末梢Ca²⁺内流有密切关系。

MECHANISM OF ANALGESIC ACTION OF HYPERIN

In previous works, we reported that Hyp (hyperin) showed strong analgesic effect, and inhibited discharges induced by multialgesics, but without anesthetic action. In this study,the analgesic mechanism of Hyp was further investigated.In the tail-flick test in mice, EGTA was shown to markly enhance the analgesic effect of Hyp and shift the dose-effect curve to the upper-left. CaCl_2 significantly antagonized the effect of Hyp and shifted the dose-effect curve to the lower-right. In the afferent discharges induced by algesics, EGTA markly elevated while cacl_2 lowered the effect of Hyp. It was also found that A_(23187), which promote influx of Ca~(2 ), could antagonize the effect of Hyp. In the frog sciatic nerves, we fouud that Hyp could significantly inhibit influx of Ca~(2 ). This finding suggests that the analgesic effect of Hyp may have close relationship with the reduction of calcium in afferent nerve endings.