The dynamics of inositol 1,4,5-trisphosphate (Ins (1,4,5)P3) production during periods of G-protein-coupled receptor-mediated Ca2+ oscillations have been investigated using the pleckstrin homology (PH) domain of phospholipase C (PLC) delta1 tagged with enhanced green fluorescent protein (eGFP-PHPLCdelta1). Activation of noradrenergic alpha1B and muscarinic M3 receptors recombinantly expressed i...

Optical methods have recently become available for continuously imaging the free concentrations of important ions and second messengers such as calcium, sodium and hydrogen inside living cells. These ion levels are found to undergo remarkable changes upon stimulation of quiescent cells with growth factors known to stimulate phosphoinositide breakdown. In serum-starved REF-52 fibroblasts, growth...

Rat pheochromocytoma (PC12) cells, persistently infected with mumps virus (MV), failed to generate full-sized stimulus-evoked action potentials (SEAPs) when examined by intracellular electrophysiological recording techniques. Application of tetrodotoxin (TTX) had little or no effect on MV-reduced SEAPs, indicating that the number of functional voltage-gated Na+ channels was decreased or their o...

Activity-induced transient increases in intracellular Ca2+ concentration ([Ca]i) trigger neuronal responses ranging from modulation of synaptic transmission to alterations in gene expression with time courses of seconds to days1–3. These changes occur through Ca2+-stimulated messenger cascades that can induce prolonged recruitment of proteins by, for example, autophosphorylation4, persistent bi...

Vagal motoneurons in slices from the guinea-pig brain stem were injected with the fluorescent [Ca2+]i indicators fura-2, furaptra, or Calcium Green-1. Spike-induced fluorescence changes were measured in the soma and dendrites and simultaneously the long-lasting afterhyperpolarization was recorded with a sharp microelectrode in the soma. Na+ spikes or Ca2+ spikes increased [Ca2+]i (measured as a...

Two different families of Na+/Ca2+ exchangers, K+-independent NCX and K+-dependent NCKX, are known. Exploiting the outward K+ gradient, NCKX is able to extrude Ca2+ more efficiently than NCX, even when the Na+ gradient is reduced. The NCKX, which was originally thought to be limited to the retinal photoreceptor, was shown recently to be widely distributed in the brain. We investigated the contr...

Calcium influx into the dendritic tufts of layer 5 neocortical pyramidal neurons modifies a number of important cellular mechanisms. It can trigger local synaptic plasticity and switch the firing properties from regular to burst firing. Due to methodological limitations, our knowledge about Ca2+ spikes in the dendritic tuft stems mostly from in vitro experiments. However, it has been speculated...

1. Intracellular recordings were made from the myoepithelial cells of the proventriculus of the marine polychaete worm Syllis spongiphila. Over-shooting responses were elicited either by carbamylcholine added to the bathing medium or by directly applied intracellular current pulses. 2. In control artificial sea water (ASW) directly applied current pulses elicited regenerative responses of 68-11...