BKCa channel act as a negativefeedback regulator in the development of cold-induced hypertension

摘要： <正>Cold is an important factor contributing to the high incidence of hypertension.In order to explore the mechanisms of cold-induced hypertension.This study observed whether large conductance calcium-activated potassium channel BK_(Ca)) on vascular smooth muscle cells(VSMC) played a role in the development of hypertension during chronic exposure to cold.Forty-eight rats were divided into cold-treated group and control group randomly,then,one subgroup of the cold-treated and one subgroup of control rats were sacrificed at 2,4,6 and 8 weeks.Systolic blood pressure started to rise after 2 weeks of cold exposure and continued to increase, reaching a maximal level by the 6th week of exposure to cold,and then pressure beginned to decrease slowly throughout the remainder of the experiment.The BK_(Ca),current and BK_(Ca) peak current density in aortic VSMC increased significantly as the time of exposure to cold went until the 6th week exposure to cold.Furthermore,the expression of L-type Cav1.2 channelα_1C subunit mRNA in the cold-treated rats were higher than those in the control rats.Cold stress increased expression of L-type Cav1.2 channelα_1d subunit mRNA, indicate that cytoplasmic Ca~(2+) concentration increased with cold-treated extended at 6 weeks in the beginning,resulting in increasing blood pressure.BKCa channel currents increased in this progress as the negative-feedback regulators of vascular tone.Our results indicated that activation of BKCa channel could reduce blood pressure(7th and 8th week) in hypertensive subjects. （共2頁）