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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)
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)
The acquired form of the long-QT syndrome (LQTS) is a major safety consideration for the development and subsequent use of both cardiac and non-cardiac drugs; it is usually associated with pharmacological inhibition of cardiac HERG-encoded potassium channels. Clomiphene is an anti-estrogen agent used extensively in the treatment of infertility and is not(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)
The aim of this study was to determine the effects of the antiestrogen agent clomiphene on cardiac anionic and cationic sarcolemmal ion channels. Whole-cell recordings were made from rat and guinea pig ventricular myocytes. Clomiphene inhibited the volume-regulated chloride current [I(Cl,vol), activated by cell swelling after hypotonic shock (approximately(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)
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)
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)
As smooth muscle cell (SMC) membrane potential (E(m)) is critical for vascular responsiveness, and arteriolar SMCs are depolarized at physiological intraluminal pressures, we hypothesized that myogenic tone impacts on dilation mediated by endothelium-derived hyperpolarization (EDH). Studies were performed on cannulated mouse cremaster arterioles [diameter,(More)