Nitric oxide (NO) donors decrease intraocular pressure (IOP) by increasing aqueous outflow facility in the trabecular meshwork (TM) and/or Schlemm's canal. However, the cellular mechanisms are unknown. Cellular mechanisms known to regulate outflow facility include changes in cell volume and cellular contractility. In this study, we investigated the effects of NO donors on outflow facility and N...

Lee, So-Young, Bo-Hwa Choi, Eun-Mi Hur, Jong-Hee Lee, Sung-Jin Lee, Chin Ok Lee, and Kyong-Tai Kim. Norepinephrine activates store-operated Ca entry coupled to large-conductance Ca -activated K channels in rat pinealocytes. Am J Physiol Cell Physiol 290: C1060–C1066, 2006. First published November 9, 2005; doi:10.1152/ajpcell.00343.2005.—Norepinephrine (NE) is one of the major neurotransmitters...

Although it is well established that diabetes impairs endothelium-dependent vasodilation, including those pathways involving vascular myocyte large-conductance Ca(2+)-activated K(+) channels (BK(Ca)), little is known about the effects of diabetes on BK(Ca) activation as an intrinsic response to contractile stimulation. We have investigated this mechanism in a model of Type 2 diabetes, the male ...

Norepinephrine (NE) is one of the major neurotransmitters that determine melatonin production in the pineal gland. Although a substantial amount of Ca(2+) influx is triggered by NE, the Ca(2+) entry pathway and its physiological relevance have not been elucidated adequately. Herein we report that the Ca(2+) influx triggered by NE significantly regulates the protein level of serotonin N-acetyltr...

Voltage-dependent large-conductance Ca2+-activated K+ channels (BK channels) are widely expressed in excitable and nonexcitable cells. BK channels exhibit diverse electrophysiological properties, which are attributable in part to alternative splicing of their alpha-subunits. BK currents have been implicated in the growth control of glial cells, and BK channels with novel biophysical properties ...

The present experiments investigated whether endothelium-derived mediators modulate the effect of natriuretic peptides in porcine coronary arteries. Rings with and without endothelium were suspended in organ chambers for isometric tension recording. Concentration-relaxation curves to C-type natriuretic peptide (CNP) and atrial natriuretic peptide (ANP) were obtained during contractions to endot...

Burnham, Matthew P., Ian T. Johnson, and Arthur H. Weston. Reduced Ca -dependent activation of large-conductance Ca -activated K channels from arteries of Type 2 diabetic Zucker diabetic fatty rats. Am J Physiol Heart Circ Physiol 290: H1520–H1527, 2006. First published November 4, 2005; doi:10.1152/ajpheart.00827.2005.—Although it is well established that diabetes impairs endotheliumdependent ...

BACKGROUND The noble gas helium induces cardiac preconditioning. Whether activation of mitochondrial K(+) channels is involved in helium preconditioning (He-PC) is unknown. The authors investigated whether He-PC (1) is mediated by activation of Ca(2+) -sensitive potassium channels, (2) results in mitochondrial uncoupling, and (3) is age dependent. METHODS Anesthetized Wistar rats were randoml...

Bowles, D. K., M. H. Laughlin, and M. Sturek. Exercise training increases K1-channel contribution to regulation of coronary arterial tone. J. Appl. Physiol. 84(4): 1225–1233, 1998.—The present study examined whether regulation of coronary tone in conduit arteries (.1.0 mm ID) is altered by exercise training. Yucatan miniature swine were treadmill trained for 16–20 wk (Ex) and compared with sede...

The present study examines possible mechanisms by which the flavonoid isokaempferide (IKPF; 5,7,4'-trihydroxy-3-methoxyflavone) from Amburana cearensis, a Brazilian medicinal plant popularly used as bronchodilator, induces relaxation of guinea-pig isolated trachea. In the trachea (with intact epithelium) contracted by carbachol, IKPF (1-1000 microM) caused a graded relaxation, and the epitheliu...