We investigated the modulation of the skeletal muscle L-type Ca2+ channel/dihydropyridine receptor in response to insulin-like growth factor-1 receptor (IGF-1R) activation in single extensor digitorum longus muscle fibers from adult C57BL/6 mice. The L-type Ca2+ channel activity in its dual role as a voltage sensor and a selective Ca2+-conducting pore was recorded in voltage-clamp conditions. P...

Axons of the type B photoreceptors form synapses with hair cells and interneurons that are involved in classical conditioning in Hermissenda. We examined the differences in the Ca2+ channels expressed in the soma and axons of the B photoreceptors by direct functional recordings of single-channel currents. Although the soma of the B cells express two Ca2+ current subtypes, a transient BayK 8644-...

Hearing relies on faithful sound coding at hair cell ribbon synapses, which use Ca2+-triggered glutamate release to signal with submillisecond precision. Here, we investigated stimulus-secretion coupling at mammalian inner hair cell (IHC) synapses to explore the mechanisms underlying this high temporal fidelity. Using nonstationary fluctuation analysis on Ca2+ tail currents, we estimate that IH...

We have investigated the effects of Ca2+ on Na+ influx through ATP-activated channels in pheochromocytoma PC12 cells using single channel current recordings. Under cell-attached patch-clamp conditions with 150 mM Na+ and 2 mM Ca2+ in the pipette, the unitary current activity showed an open level of about -4.3 pA at -150 mV. The channel opening was interrupted by flickery noise as well as occasi...

The present study shows that the chemically novel nondihydropyridine Ca2+ antagonist, Ro 40-5967, blocks T-type divalent ion currents in vascular muscle cells. T-type Ca2+ channels were blocked selectively and completely by therapeutic concentrations of 1 to 10 mumol/L Ro 40-5967, at which there was only 25% to 70% block of L-type Ca2+ currents. Using the combination of Ro 40-5967 and nisoldipi...

The expression of voltage-gated calcium (Ca2+) channel activity in brain cells is known to be important for several aspects of neuronal development. In addition, excessive Ca2+ influx has been linked clearly to neurotoxicity both in vivo and in vitro; however, the temporal relationship between the development of Ca2+ channel activity and neuronal survival is not understood. Over a period spanni...

Erythropoietin (Epo) induces a dose-dependent increase in intracellular free Ca2+ ([Ca2+]i) in human erythroblasts, which is dependent on extracellular Ca2+ and blocked by high doses of nifedipine or Ni2+. In addition, pretreatment of human erythroblasts with mouse antihuman erythropoietin receptor antibody but not mouse immunopure IgG blocked the Epo-induced [Ca2+]i increase, indicating the sp...

Canine cardiac Purkinje cells contain both L- and T-type calcium currents, yet the single Ca2+ channels have not been characterized from these cells. Additionally, previous studies have shown an overlap between the steady-state inactivation and activations curves for L-type Ca2+ currents, suggesting the presence of L-type Ca2+ "window" current. We used the on-cell, patch-clamp technique to stud...

Cytosolic free Ca2+ has been shown to have both activating and inhibitory effects upon the inositol (1,4,5) trisphosphate receptor (InsP3R) during intracellular Ca2+ release. The effects of cytosolic free Ca2+ on the InsP3R have already been monitored using cerebellar microsomes (containing InsP3R) incorporated into planar lipid bilayers [Bezprozvanny, Watras and Ehrlich (1991) Nature (London) ...

Previous studies have shown that nitric oxide (NO) inhibits carotid body sensory activity. To begin to understand the cellular mechanisms associated with the actions of NO in the carotid body, we monitored the effects of NO donors on the macroscopic Ca2+ current in glomus cells isolated from rabbit carotid bodies. Experiments were performed on freshly dissociated glomus cells from adult rabbit ...