The understanding of the molecular properties and structure-function relations of ion channels has advanced tremendously during the past few years. In this review I will try to summarize briefly the current advances in the field of calcium channel proteins and outline the problems facing researchers at present. I will concentrate exclusively on uertebrate voltage-dependent Ca*+ channels, becaus...

NAADP (nicotinic acid-adenine dinucleotide phosphate) is a potent Ca2+-mobilizing messenger implicated in many Ca2+-dependent cellular processes. It is highly unusual in that it appears to trigger Ca2+ release from acidic organelles such as lysosomes. These signals are often amplified by archetypal Ca2+ channels located in the endoplasmic reticulum. Recent studies have converged on the TPCs (tw...

It is well established that in the adult mammalian heart, small amounts of Ca2+ entry via voltage-dependent sarcolemmal Cav1.2 L-type Ca2+ channels can trigger the release of a significant amount of Ca2+ from the sarcoplasmic reticulum (SR) that is followed by muscle contraction, a process known as excitation–contraction (EC) coupling. However, for the developing mammalian and avian hearts, ear...

Ca2+ release through ryanodine receptors (RyRs) in the sarcoplasmic reticulum is a key element of excitation-contraction coupling in muscle. In arterial smooth muscle, Ca2+ release through RyRs activates Ca2+-sensitive K+ (KCa) channels to oppose vasoconstriction. Local Ca2+ transients ("Ca2+ sparks"), apparently caused by opening of clustered RyRs, have been observed in smooth and striated mus...

Calcium- and sodium- activated potassium channels are members of the 6TM family K which comprises voltage-gated KV subfamilies, including KCNQ subfamily, EAG subfamily (which includes hERG channels), Ca2+-activated Slo (actually with 6 or 7TM) Ca2+- Na+-activated SK (nomenclature as agreed by NC-IUPHAR Subcommittee on sodium-activated [126]). As for 2TM family, pore-forming a subunits form tetr...

Compelling evidence supports contributions of glutamate receptor overactivation ('excitotoxicity') to neurodegeneration in both acute conditions, such as stroke, and chronic neurodegenerative conditions, such as amyotrophic lateral sclerosis. However, anti-excitotoxic therapeutic trials, which have generally targeted highly Ca2+ permeable NMDA-type glutamate channels, have to date failed to dem...

In bovine chromaffin cells, the Ca2+ channels involved in exocytosis are effectively inhibited by ATP and opioids that are coreleased with catecholamines during cell activity. This autocrine loop causes a delay in Ca2+ channel activation that is quickly removed by preceding depolarizations. Changes in Ca2+ channel gating by secreted products thus make it possible to correlate Ca2+ channel activ...

The goal of the present study was to determine the physiologically relevant mechanisms for forskolin-induced relaxation of intact rat tail artery. We stimulated deendothelialized rat tail artery with phenylephrine and then relaxed the tissue with the addition of forskolin, a specific activator of adenylyl cyclase. We measured membrane potential with the use of microelectrodes, estimated intrace...

Particular types of amacrine cells of the vertebrate retina show oscillatory membrane potentials (OMPs) in response to light stimulation. Historically it has been thought the oscillations arose as a result of circuit properties. In a previous study we found that in some amacrine cells, the ability to oscillate was an intrinsic property of the cell. Here we characterized the ionic mechanisms res...

Vasodilatory factors produced by the endothelium are critical for the maintenance of normal blood pressure and flow. We hypothesized that endothelial signals are transduced to underlying vascular smooth muscle by vanilloid transient receptor potential (TRPV) channels. TRPV4 message was detected in RNA from cerebral artery smooth muscle cells. In patch-clamp experiments using freshly isolated ce...