We have studied voltage-dependent inhibition of N-type calcium currents to investigate the effects of G-protein modulation-induced alterations in channel gating on action potential-evoked calcium current. In isolated chick ciliary ganglion neurons, GTPgammaS produced voltage-dependent inhibition that exhibited slowed activation kinetics and was partially relieved by a conditioning prepulse. Usi...

We present a simplified lattice model to study calcium dynamics in the endoplasmic reticulum membrane. Calcium channels and calcium ions are placed in two interpenetrating square lattices which are connected in two ways: (i) via calcium release and (ii) because transitions between channel states are calcium dependent. The opening or closing of a channel is a stochastic process controlled by two...

The calcium channel plays a key role in controlling many physiological processes in the body. Drugs that block the calcium channel have proven clinically effective for the treatment of a multitude of cardiovascular disorders. The elucidation of the precise mechanism of action of these drugs involves cloning the calcium channels on which they act. Genetic manipulation of these cloned channels is...

putative calcium channel specific to sperm tails may be the best target yet for a male contraceptive. The protein, dubbed CatSper, was discovered in a homology search by David Clapham and colleagues of Harvard Medical School, Boston, MA. CatSper looks like a calcium channel, although Clapham could not detect a calcium current in transfected cells, probably because another component of the chann...

A simple model of calcium channel inactivation has been developed, based on the accumulation of calcium ions at the inner mouth of the channel and on their binding to a receptor which inactivates the channel. A qualitative analysis has shown that upon an appropriate choice of parameters corresponding to the cell structure and to kinetic properties of its components, the calcium dependent inacti...

A few observations and much reasoning leads to error; many observations and a little reasoning to truth.-Alexis Carrell oncerns have been raised about safety of calcium channel blockers in patients with heart failure since their introduction into cardiovascular medicine more than 25 years ago. By inhibiting the influx of calcium into myocardial cells, calcium channel-blocking drugs can depress ...

We examine how a variety of cationic channels discriminate between ions of differing charge. We construct models of the KcsA potassium channel, voltage gated sodium channel and L-type calcium channel, and show that they all conduct monovalent cations, but that only the calcium channel conducts divalent cations. In the KcsA and sodium channels divalent ions block the channel and prevent any furt...

putative calcium channel specific to sperm tails may be the best target yet for a male contraceptive. The protein, dubbed CatSper, was discovered in a homology search by David Clapham and colleagues of Harvard Medical School, Boston, MA. CatSper looks like a calcium channel, although Clapham could not detect a calcium current in transfected cells, probably because another component of the chann...

putative calcium channel specific to sperm tails may be the best target yet for a male contraceptive. The protein, dubbed CatSper, was discovered in a homology search by David Clapham and colleagues of Harvard Medical School, Boston, MA. CatSper looks like a calcium channel, although Clapham could not detect a calcium current in transfected cells, probably because another component of the chann...

5-Hydroxytryptamine (5-HT) is a potent pulmonary vasoconstrictor and contributes to hypoxic pulmonary vasoconstriction and pulmonary arterial hypertension. Small intrapulmonary vessels are very sensitive to hypoxia and play a major role for blood flow regulation in the lung. Thus we have investigated the mechanisms involved in the calcium signal to 5-HT in rat small intrapulmonary artery (IPA)....