American journal of hypertension
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Numerous studies have emphasized the important role of altered Ca(2+) channel function in hypertension. We previously showed that Ca(2+) currents measured in myocytes isolated from both Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHR) small mesenteric arteries closely correlated with systolic blood pressure (BP) during normal development. The purpose of the present experiments was to determine whether antihypertensive therapy with an angiotensin converting enzyme inhibitor normalizes Ca(2+) channel function in SHR myocytes along with BP. ⋯ The I(K) measured from holding potentials of -60 and -20 mV were significantly smaller in treated SHR and WKY compared to their untreated counterparts, as was the component of I(K) measured in the presence of 100 nmol/L iberiotoxin. These results show that ramipril treatment decreases arterial pressure and Ca(2+) channel function in SHR as expected but unexpectedly also decreases I(K) in both WKY and SHR. These results suggest that angiotensin may have a BP independent effect on ion channel function in arterial smooth muscle.