金丝桃甙中枢镇痛作用及其机制的研究

STUDY ON THE CENTRAL ANALGESIC ACTION AND ITS MECHANISM OF HYPERIN (HYP)

金丝桃甙5μg/只(20g)侧脑室注射,经小鼠甩尾试验,热板法测痛,证实其有显著的中枢镇痛作用,其作用效价强度约等吗啡的1/20;相当于外周给药(腹腔给药)的100倍。用放射免疫法测得各脑区亮氨酸脑啡肽与金丝桃甙镇痛作用无关,纳络酮亦未能拮抗金丝桃甙的镇痛作用,但侧脑室注射CaCl_2和EGTA可分别拮抗和增强金丝桃甙的镇痛作用,并用原子吸收光谱法测得金丝桃甙产生镇痛作用时,小鼠脑内Ca^(2+)含量显著地减少。提示金丝桃甙中枢镇痛作用可能与降低脑内Ca^(2+)含量有密切关系。

After icv administration, the analgesic action of Hyp was found on the tail-flick and hot-plate tests. The analgesic action potency of icv Hyp was approximately equal to 1 ~20 of morphine and was about 100 times as potent as sc administration. No effect was seen on the analgesic action of Hyp after ip naloxone, the analgesic action of Hyp was no concern of L-enkephalin contents in discrete regions of rat brain either. But icv EGTA markedly enhanced while icv CaCl2 antagonized the analgesic action of Hyp. It was also found that calcium ion content in mice brain markedly reduced when the analgesic action of Hyp appeared. These results suggest that Hyp have significant central analgesic action and the central analgesic action of Hyp may relate to reducing of calcium ion in brain.