Xi, Qi, Dilyara Tcheranova, Helena Parfenova, Burton Horowitz, Charles W. Leffler, and Jonathan H. Jaggar. Carbon monoxide activates KCa channels in newborn arteriole smooth muscle cells by increasing apparent Ca sensitivity of -subunits. Am J Physiol Heart Circ Physiol 286: H610–H618, 2004. First published October 16, 2003; 10.1152/ajpheart.00782.2003.—Carbon monoxide (CO) is a gaseous vasodil...

BACKGROUND AND PURPOSE Small conductance calcium-activated potassium (KCa 2.x) channels have a widely accepted canonical function in regulating cellular excitability. In this study, we address a potential non-canonical function of KCa 2.x channels in breast cancer cell survival, using in vitro models. EXPERIMENTAL APPROACH The expression of all KCa 2.x channel isoforms was initially probed us...

It has been suggested that impairment of smooth muscle cell (SMC) function by alterations in the Ca -activated K (KCa) channels accounts for the reduction in coronary reserve during left ventricular hypertrophy (LVH). However, this hypothesis has not been fully investigated. The main goal of this study was to assess whether the properties of KCa channels in coronary SMCs were altered during LVH...

In some but not all arterial beds, smooth muscle cell calcium-activated K+ channels (KCa channels) play a central role in the mediation of the vasodilator response to nitric oxide (NO) and other nitrates. We investigated the effect of nitrates on KCa channels in the relaxation of human coronary arteries by means of isometric contraction experiments in arterial rings. We also measured whole-cell...

The functional expression of Ca2+-activated K+ channels (KCa) in developing chick ciliary ganglion (CG) neurons requires interactions with target tissues and preganglionic innervation. Here, we show that the stimulatory effects of target tissues are mediated by an isoform of TGFbeta. Exposure of cultured CG neurons to TGFbeta1, but not TGFbeta2 or TGFbeta3, caused robust stimulation of KCa. The...

The functional expression of large-conductance (BK-type) Ca -activated K (KCa ) channels was examined in developing chick lumbar motoneurons (LMNs) between embryonic day 6 (E6) and E13 using patch-clamp recording techniques. The macroscopic KCa current of E13 LMNs is inhibited by iberiotoxin and resistant to apamin. The average macroscopic KCa density was low before E8 and increased 3.3-fold by...

Nitric oxide (NO) hyperpolarizes intestinal smooth muscle cells. This study was designed to determine the mechanism whereby NO activates KCa channels of circular smooth muscle of the rabbit colon. Transmural biopsies of the rabbit colon were stained for NADPH-diaphorase. Freshly dispersed circular smooth muscle cells were studied in the whole cell configuration, as well as in on-cell and excise...

The developmental expression of Ca2+-activated K+ channels (KCa) in chick ciliary ganglion (CG) neurons is regulated by a target-derived avian isoform of TGFbeta1, which evokes a robust increase in the number of functional large-conductance (BK) KCa channels but which produces no change in their kinetics. However, CG neurons express multiple KCa channel subtypes. Here we show that TGFbeta1 regu...

Han, Jin, Nari Kim, Hyun Joo, and Euiyong Kim. Ketamine blocks Ca2 -activated K channels in rabbit cerebral arterial smooth muscle cells. Am J Physiol Heart Circ Physiol 285: H1347–H1355, 2003; 10.1152/ajpheart.00194. 2003.—Although ketamine and Ca2 -activated K (KCa) channels have been implicated in the contractile activity regulation of cerebral arteries, no studies have addressed the specifi...

The role of I(KCa) in cardiac repolarization remains controversial and varies across species. The relevance of the current as a therapeutic target is therefore undefined. We examined the cellular electrophysiologic effects of I(KCa) blockade in controls, chronic heart failure (HF) and HF with sustained atrial fibrillation. We used perforated patch action potential recordings to maintain intrins...