OBJECTIVE The present study tested the hypothesis that gestational hypoxia up-regulates protein kinase C (PKC) and inhibits calcium-activated potassium channels (KCa)-mediated relaxations of uterine arteries in pregnancy. STUDY DESIGN Uterine arteries were isolated from nonpregnant (NPUA) and pregnant (PUA) (~140 day gestation) sheep maintained at either sea level or high altitude (3,820 m fo...

With the use of the patch-clamp technique, five kinds of stretch-activated (SA) ion channels were identified on the basis of their single-channel conductances and ion selectivities in cultured chick ventricular myocytes. Because a high-conductance K+-selective channel predominated among these channels, we concentrated on characterizing its properties mostly using excised inside-out patches. Wit...

The molecular mechanism of the regulation of Ca2+ pump ATPase by phospholamban in cardiac sarcoplasmic reticulum was examined using synthetic peptides of phospholamban and purified Ca2+ pump ATPase from cardiac sarcoplasmic reticulum. The phospholamban monomer of 52 amino acid residues contains two distinct domains, the cytoplasmic (amino acids 1-30) and the transmembrane (amino acids 31-52) do...

The role of NO in the regulation of the mechanical properties of conduit arteries is controversial in humans, and the involvement of an endothelium-derived hyperpolarizing factor (EDHF), acting through calcium-activated potassium (KCa) channels, has never been investigated at this level in vivo. We assessed in healthy volunteers, after oral administration of aspirin (500 mg), the effect of loca...

Cyclin-dependent kinases (CDKs) control cell cycle progression through timely coordinated phosphorylation events. Two kinesin-like proteins that interact with CDKA;1 were identified and designated KCA1 and KCA2. They are 81% identical and have a similar three-partite domain organization. The N-terminal domain contains an ATP and microtubule-binding site typical for kinesin motors. A green fluor...

Wade, Gregory R., Lisanne G. Laurier, Harold G. Preiksaitis, and Stephen M. Sims. Delayed rectifier and Ca21-dependent K1 currents in human esophagus: roles in regulating muscle contraction. Am. J. Physiol. 277 (Gastrointest. Liver Physiol. 40): G885–G895, 1999.—We have examined K1 channels and their function in human esophageal smooth muscle using perforated patch recording, RT-PCR to identify...

Epoxyeicosatrienoic acids (EETs) relax various smooth muscles by increasing outward K+movement, but the molecular mode of action of EET regioisomers remains to be clarified. The effects of EETs were investigated on bovine airway smooth muscle tone and on reconstituted Ca2+-activated K+(KCa) channels. 5,6-EET and 11,12-EET induced dose-dependent relaxations of precontracted bronchial spirals. Th...