Reduced Effects of Isoprenaline on the Membrane Potential of Aortic Smooth Muscle from Rats Pre‐ and During Hypertension

Abstract

The aim of this study was to determine whether aortic membrane potential, or the effects of potassium chloride (KCl) and isoprenaline on that potential, were different in the spontaneously hypertensive rat (SHR), pre-hypertension and during hypertension. Thus we describe the effects of KCl and isoprenaline on the membrane potential of aortae from 5-and 14-week-old Wistar Kyoto normotensive rats (WKY) and SHR. Five-week-old SHR are prehypertensive. Membrane potentials and KCl-induced depolarization were similar for aortae from 5- and 14-week-old WKY and SHR. Isoprenaline at 10−8 M fully reversed KCl-induced depolarization in aortae from WKY but not in those from 5- and 14-week-old SHR. In conclusion, we have shown a selective defect in the capacity of isoprenaline to reverse KCl-induced depolarization in SHR pre- and during hypertension.