摘要
目的初步了解眼镜蛇毒MP成分与M受体结合的亚型选择性。方法制备大鼠大脑皮层组织和大鼠心肌组织两种M受体膜蛋白底物。采用放射配体结合法,分别测定眼镜蛇毒MP成分对[3H]QNB与这两种膜蛋白底物结合的抑制百分率和IC50值,分析MP与M受体结合的亚型选择性。结果 MP均能完全抑制[3H]QNB与这两种膜蛋白底物的结合。大鼠大脑皮层组中,MP的抑制行为呈两相式:第Ⅰ相的抑制率为25%,IC50=0.4 nmol·L-1;第Ⅱ相的抑制率为100%,IC50=248.8 nmol·L-1。心肌组MP的IC50值为22.1 nmol·L-1,约为皮层组第Ⅰ相的55倍、第Ⅱ相的1/10。结论 MP对M受体的结合具有亚型选择性。
Objective To investigate the selectivity of the MP component from the venom of Chinese cobra （ Naja atra ） for muscarinic receptor subtypes. Methods The receptor membrane protein substrates from the rat cerebral cortex and rat myocardium were prepared. To evaluate the effect of MP on the binding of [ 3 H ] QNB to the two membrane protein substrates, the inhibition percentage and ICso were respectively determined by radioligand binding assay. Then the subtype selectivity of MP for muscarinic receptors was analyzed. Results The binding of [ 3H ] QNB to the two membrane proteins was inhibited completely by MP. In the rat cerebral cortex group, the inhibition of MP was shown in two phases, In phase Ⅰ , the inhibition percentage was 25% with an ICs0 value of O. 4 nmol ·L^-1. In phase Ⅱ ,the inhibition percentage was 100% with an ICs0 value of 248.8 nmol ·L^-1. In the myocardial group, MP showed complete inhibition with an IC50 value of 22.1 nmol ·L^-1 ,which was about 55 times that in phase I and 10 percent lower than in phase 11 in comparison with the cerebral cortex group. Conclusion The MP component from cobra venom is shown to bind selectively to muscarinic receptor subtypes.
出处
《解放军药学学报》
CAS
2012年第5期385-388,共4页
Pharmaceutical Journal of Chinese People's Liberation Army
基金
福建省青年科技人才创新项目
No.2008F3084
