Arterial hyperpolarization to acetylcholine (ACh) reflects coactivation of K(Ca)3.1 (IK(Ca)) channels and K(Ca)2.3 (SK(Ca)) channels in the endothelium that transfers through myoendothelial gap junctions and diffusible factor(s) to affect smooth muscle relaxation (endothelium-derived hyperpolarizing factor [EDHF] response). However, ACh can differentially activate K(Ca)3.1 and K(Ca)2.3 channels...

Arterial smooth muscle cell large-conductance Ca(2+)-activated potassium (K(Ca)) channels have been implicated in modulating hypoxic dilation of systemic arteries, although this is controversial. K(Ca) channel activity in arterial smooth muscle cells is controlled by localized intracellular Ca(2+) transients, termed Ca(2+) sparks, but hypoxic regulation of Ca(2+) sparks and K(Ca) channel activa...

The molecular mechanisms underlying the effects of nitric oxide (NO) and carbon monoxide (CO), individually and collectively, on large-conductance calcium-activated K(+) (K(Ca)) channels were investigated in rat vascular smooth muscle cells (SMCs). Both NO and CO increased the activity of native K(Ca) channels. Dehydrosoyasaponin-I, a specific agonist for beta subunit of K(Ca) channels, increas...

The effects of elevated potassium ion (K) concentration on radioactive calcium (Ca) movements and distribution were investigated in media-intimal strips prepared from rabbit aortic smooth muscle. Ca uptake was measured in either normal (1.5 rriM Ca ) or low-Ca (0.1 mM Ca ) solutions. In low-Ca solutions, elevating the K concentration either by substituting equimolar (165.4 IHM) K for sodium (Na...

Small-conductance calcium-activated potassium channels (K(Ca)2) are essential components involved in the modulation of neuronal excitability, underlying learning and memory. Recent evidence suggests that K(Ca)2 channel activity reduces synaptic transmission in a postsynaptic NMDA receptor-dependent manner and is modulated by long-term potentiation. We used radioactive in situ hybridization and ...