| Background: In recent years, results of some researches indicated that there were two contractive mechanisms in smooth muscle cell: firstly, improving [Ca++]i can arose contraction through myosin light chain kinase acting on myosin light chain; secondly, was to influencing calcium sensibitity, the mechanism come from by restraining myosin light chain phosphatase. Higher calcium sensibitity can produce higher contraction at the condition of the same [Ca++]i. The signal transductional pathway of calcium sensibitity is that agonists activate RhoA through G-protein-coupled receptor, activate RhoA kinase of the downstream of RhoA, phosphate the regulational subunit of myosin light chain phosphatase, and refrain myosin light chain phosphatase to refrain the de -phosphate myosin light chain. There were many researches of calcium sensibitity at abroad , abut how Emodin can influencecalcium sensibitity has not been reported . Aim: To investigate how Emodin influence calcium sensibitity.Method: Cells were isolated from the muscle layers of Wistar rat stomach by enzymatic digestion. Intracellular free calcium ions level of smooth muscle cell was controlled by the technique of calcium claw . To investigate Emodin whether effects G-protein-coupled pathway , the cells were divided into 4 groups by random:Emodin group, GDPBs group, Emodin and GDPBs group , and control group. Every group was divided 5 dosage levels. In Emodin group, its levels of concentration werel, 5, 10, 50, 100 u mol/L; in GDPBs group, were 10, 50, 100, 500, 1000 u mol/L ;in Emodin and GDPBs group ,were 1+10,5+50,10+100,50+500,100+1000 u mol/L .Then to investigate Emodin whether effects RhoA, the cells were divided into 2 groups by random: Emodin group, Emodin and C3-transferase group. Celluar length was measured by computerized image micrometry. RhoA distribution at rest state or after stimulation was measured with laster scanning confocal- microscopy, and the variation of RhoA protein... |
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