Uterine vascular tone significantly decreases whereas uterine blood flow dramatically increases during pregnancy. However, the complete molecular mechanisms remain elusive. We hypothesized that increased Ca(2+)-activated K(+) (BK(Ca)) channel activity contributes to the decreased myogenic tone of uterine arteries in pregnancy. Resistance-sized uterine arteries were isolated from nonpregnant and...

Cardiac Purkinje fibers play an important role in cardiac arrhythmias, but no information is available about ionic currents in human cardiac Purkinje cells (PCs). PCs and midmyocardial ventricular myocytes (VMs) were isolated from explanted human hearts. K(+) currents were evaluated at 37 degrees C with whole cell patch clamp. PCs had clear inward rectifier K(+) current (I(K1)), with a density ...

The contribution of sympathetic constrictor impulses to arteriolar tone is now recognized as playing an important though sometimes variable role in the maintenance of increased peripheral resistance in some patients with hypertension. However, lack of a clear understanding of the exact nature of autonomic influences and of their importance in relation to other pressor factors has complicated th...

BRADY, ROSCOE O., CONSTANTINE S. SPYROPOULOS AND ICHITI TASAKI. htra-axonal injection of biologically active materiak n improved method for injection of chemicals into the squid giant axon is described. A large number of metabolically active materials were found to be without any effect upon the action potential. Tetraethylammonium chloride produced a striking prolongation of the action potenti...

Shaker-related Kv1 channels contain four channel-forming alpha subunits. Subfamily member Kv1.1 often occurs oligomerized with Kv1.2 alpha subunits in synaptic membranes, and so information was sought on the influence of their positions within tetramers on the channels' properties. Kv1.1 and 1.2 alpha genes were tandem linked in various arrangements, followed by expression as single-chain prote...