Extracellular application of tetraethylammonium (TEA) has been shown to elicit a prolonged synaptic potentiation in the CA1 region of the hippocampus that is unaffected by NMDA receptor antagonists, but is blocked by antagonists to voltage-dependent calcium channels (Aniksztejn and Ben-Ari, 1991; Huang and Malenka, 1993). In the present study the relation between TEA-induced potentiation and NM...

The effects of platelet-activating factor (PAF) antagonists on the agonist-induced increase in cytosolic free calcium concentration, [Ca2+]i, in human vascular endothelial cells grown in monolayer were investigated by a continuous superfusion technique using a calcium fluorescent probe, fura-2. PAF caused a small but dose-dependent increase in [Ca2+]i. Seven structurally dissimilar PAF antagoni...

Using intracellular recording, we studied how several muscarinic antagonists affected the evoked endplate potentials in singly and dually innervated endplates of the levator auris longus muscle from 3 to 6-day-old rats. In dually innervated fibers, a second endplate potential (EPP) may appear after the first one when we increase the stimulation intensity. The lowest and highest EPP amplitudes a...

We determined sources of activator calcium for prostanoid-induced cerebrovascular constriction by measuring isometric tension and calcium-45 ("Ca) fluxes in bovine middle cerebral arteries. Constriction induced by prostaglandin F^ or the stable thromboxane A2 analogue SQ-26,655 was near-maximally inhibited in calcium-deficient solutions but only partially inhibited by calcium antagonists (10~ M...

We determined sources of activator calcium for prostanoid-induced cerebrovascular constriction by measuring isometric tension and calcium-45 (45Ca) fluxes in bovine middle cerebral arteries. Constriction induced by prostaglandin F2 alpha or the stable thromboxane A2 analogue SQ-26,655 was near-maximally inhibited in calcium-deficient solutions but only partially inhibited by calcium antagonists...

BACKGROUND Perioperative bronchospasm refractory to β agonists continues to challenge anesthesiologists and intensivists. The TMEM16A calcium-activated chloride channel modulates airway smooth muscle (ASM) contraction. The authors hypothesized that TMEM16A antagonists would relax ASM contraction by modulating membrane potential and calcium flux. METHODS Human ASM, guinea pig tracheal rings, o...

OBJECTIVE Recent guidelines by the National Institute for Health and Clinical Excellence (NICE) and the American College of Cardiology/American Heart Association/European Society of Cardiology (ACC/AHA/ESC) on rate control management for chronic atrial fibrillation have relegated digoxin to second line treatment, recommending instead the use of beta-blockers or rate limiting calcium antagonists...

The purpose of this study was to investigate the factors controlling membrane permeability to potassium of smooth muscle cells from rat aorta stimulated by depolarization. The increase 42K+ efflux (change in the rate constant) induced by depolarization (application of high concentrations of potassium chloride) was inhibited significantly by the calcium antagonists diltiazem and nisoldipine. Par...

The purpose of this study was to investigate the factors controlling membrane permeability to potassium of smooth muscle cells from rat aorta stimulated by depolarization. The increase in K + efflux (change in the rate constant) induced by depolarization (application of high concentrations of potassium chloride) was inhibited significantly by the calcium antagonists diltiazem and nisoldipine. P...