NW Angiotensin II inhibits and alters kinetics of voltage-gated K+ channels of rat arterial smooth muscle

giotensin II inhibits and alters kinetics of voltage-gated K1 channels of rat arterial smooth muscle. Am J Physiol Heart Circ Physiol 281: H2480-H2489, 2001.—The vasoconstrictor angiotensin II (ANG II) inhibits several types of K1 channels. We examined the inhibitory mechanism of ANG II on volt-age-gated K1 (KV) currents (IKV) recorded from isolated rat arterial smooth muscle using patch-clamp techniques. Appli-cation of 100 nM ANG II accelerated the activation of IKV but also caused inactivation. These effects were abolished by the AT1 receptor antagonist losartan. The protein kinase A (PKA) inhibitor Rp-cyclic 39,59-hydrogen phosphothioate adenosine (100 mM) and an analog of diacylglycerol, 1,2-dioctanyoyl-rac-glycerol (2 mM), caused a significant reduc-tion of IKV. Furthermore, the combination of 5 mM PKA inhibitor peptide 5–24 (PKA-IP) and 100 mM protein kinas