Kathryn H. Yuill

Learn More
Pyrethroid insecticides are known to modify neuronal sodium channels, inducing persistent, steady-state sodium current at depolarized membrane potentials. Cardiac myocytes are also rich in sodium channels but comparatively little is known about the effect of pyrethroids on the heart, or on the cardiac sodium channel isoform. In the present study therefore,(More)
We have investigated the contribution to ionic selectivity of residues in the selectivity filter and pore helices of the P1 and P2 domains in the acid sensitive potassium channel TASK-1. We used site directed mutagenesis and electrophysiological studies, assisted by structural models built through computational methods. We have measured selectivity in(More)
Nitric oxide-mediated vasodilatation has previously been attributed to the uncharged form of the molecule (NO(•)), but increasing evidence suggests that nitroxyl (HNO) may play a significant role in endothelium-dependent relaxation. The aim of this study was to investigate the mechanisms underlying HNO-mediated vasodilatation in phenylephrine(More)
We have studied pH sensitivity and ionic selectivity of the tandem pore K+ channel TASK-1 heterologously expressed in Xenopus oocytes. We fit pH sensitivity assuming that only one of the two residues H98 need be protonated for channels to be shut. The effect of protons was weakly voltage dependent with a pK a of 6.02 at +40 mV. Replacement of His (H98D,(More)
Mitochondria are proposed to be a major oxygen sensor in hypoxic pulmonary vasoconstriction (HPV), a unique response of the pulmonary circulation to low oxygen tension. Mitochondrial factors including reactive oxygen species, cytochrome c, ATP, and magnesium are potent modulators of voltage-gated K(+) (K(v)) channels in the plasmalemmal membrane of(More)
BACKGROUND/AIMS In cerebral arteries, nitric oxide (NO) release plays a key role in suppressing vasomotion. Our aim was to establish the pathways affected by NO in rat middle cerebral arteries. METHODS In isolated segments of artery, isometric tension and simultaneous measurements of either smooth muscle membrane potential or intracellular [Ca(2+)](More)
OBJECTIVE   To assess the influence of blocking smooth muscle large conductance Ca(2+) -activated K+ channels and voltage-gated K+ channels on the conducted dilation to ACh and isoproterenol. MATERIALS AND METHODS   Rat mesenteric arteries were isolated with a bifurcation, triple-cannulated, pressurized and imaged using confocal microscopy. Phenylephrine(More)
Voltage-gated K(+) (Kv) channels are important in the regulation of pulmonary vascular function having both physiological and pathophysiological implications. The pulmonary vasculature is essential for reoxygenation of the blood, supplying oxygen for cellular respiration. Mitochondria have been proposed as the major oxygen-sensing organelles in the(More)
To date, data regarding the cellular electrophysiology of the atrioventricular node (AVN) have derived from AVN cells isolated from the rabbit heart. The aim of this study was to characterise for the first time the electrophysiological properties of single cells isolated from the AVN of the guinea-pig heart. Cells were isolated from the AVN region by a(More)