In Vitro Effect Of Low Dose Bradykinin To Calcium-activated Potassium Currents On C6 Blood-brain Tumor Barrier Of Rats

ObjectiveWe had known that intracarotid infusion of RMP - 7 which has similar function with bradykinin can elevate the permeability of antitumor agents such as carbonate , so the life of patients with glicoma will be prolonged obviously and then the bradykinin had been used to open the blood brain barrier selectively for anti-tumor agents reaching the brain tissue. It is said that the bradykinin can open the blood brain barrier selectively for it may combine with B2 receptor in capillary epithelium, and activate the NO synthetic enzyme to produce much more in-tracellular cGMP. It is also said that there are calcium - activated potassium channel and ATP - dependent potassium channel on the brain capillary epithelium. The bradykinin infusion can increase the concentration of intracellular calcium ion, and then stimulate the calcium - activated potassium channel. So we know that calcium - activated potassium channel and ATP - dependent potassium channel play a important role in the vessel dilatation which caused by bradykinin, NO and cGMP. But we suspect the conclusion. So we do the research; the study on the mechanism of bradykinin opening blood brain barrier was took on animal mainly. It is difficult to clarify the key factors for there are so many effective factors in vivo study. In our study, we take whole cell patch clamp method to observe the effect on the calcium - activated potassium currents of brain microvascular endothelial cells and C6 cells by bradykinin in vitro. So we can explain the mechanism of bradykinin opening blood brain barrier selectively; clarify the effect of the calcium - activated potassium channel during the process.