Altered K _ATP Channel Subunits Expression and Vascular Reactivity in Spontaneously Hypertensive Rats With Age

Abstract:

ATP-sensitive potassium (K _ATP) channels link membrane excitability to metabolic state to regulate a series of biological activities including the vascular tone. However, their ability to influence hypertension is controversial. Here we aim to investigate possible alteration of K _ATP channel in vascular smooth muscles (VSMs) during hypertension development process. In this study, we used 16-week-old spontaneously hypertensive rats (SHRs), 49-week-old SHRs, and their age-matched Wistar-Kyoto rats to study the expression of VSM K _ATP subunits at the mRNA and protein level and the function of VSM K _ATP by observing the relaxation reactivity of isolated aorta rings to K _ATP modulators. We found that the expression of VSM K _ATP subunits Kir6.1 and sulfonylurea receptor (SUR2B) decreased during hypertension. Moreover, the expression of SUR2B and Kir6.1 in 49-week-old SHRs decreased much more than that in 16-week-old SHRs. Furthermore, the aorta rings of 49-week-old SHRs showed lower reactivity to diazoxide than 16-week-old SHRs. This study suggests that K _ATP channels in VSM subunits Kir6.1 and SUR2B contribute to modify the functionality of this channel in hypertension with age.