Cell suspensions obtained from Nicotiana plumbaginifolia plants stably expressing the apoaequorin gene were used to analyze changes in cytosolic free calcium concentrations ([Ca(2+)](cyt)) in response to elicitors of plant defenses, particularly cryptogein and oligogalacturonides. The calcium signatures differ in lag time, peak time, intensity, and duration. The intensities of both signatures d...

Degranulation of mast cells in response to Ag or the calcium mobilizing agent, thapsigargin, is dependent on emptying of intracellular stores of Ca(2+) and the ensuing influx of external Ca(2+), also referred to as store-operated calcium entry. However, it is unlikely that the calcium release-activated calcium channel is the sole mechanism for the entry of Ca(2+) because Sr(2+) and other divale...

Two processes dominate voltage-gated calcium channel (Ca(V)) inactivation: voltage-dependent inactivation (VDI) and calcium-dependent inactivation (CDI). The Ca(V)beta/Ca(V)alpha(1)-I-II loop and Ca(2+)/calmodulin (CaM)/Ca(V)alpha(1)-C-terminal tail complexes have been shown to modulate each, respectively. Nevertheless, how each complex couples to the pore and whether each affects inactivation ...

The L-type calcium current (I(Ca)) is important in sustaining propagation during discontinuous conduction. In addition, I(Ca) is altered during discontinuous conduction, which may result in changes in the intracellular calcium transient. To study this, we have combined the ability to monitor intracellular calcium concentration ([Ca(2+)](i)) in an isolated cardiac cell using confocal scanning la...

BACKGROUND Volatile anesthetics exert their negative chronotropic and inotropic effects, in part by depressing the L- and T-type calcium channels. This study examines and compares the dose-dependent effects of isoflurane on atrial L- and T-type calcium currents (I(Ca,L) and I(Ca,T)) and ventricular I(Ca,L). METHODS Whole cell I(Ca) was recorded from enzymatically isolated guinea pig cardiomyo...

We investigated whether nitric oxide (NO) upregulates a cyclic nucleotide-gated (CNG) channel and whether this contributes to sustained elevation of intracellular calcium levels ([Ca(2+)](i)) in porcine pulmonary artery endothelial cells (PAEC). Exposure of PAEC to an NO donor, NOC-18 (1 mM), for 18 h increased the protein and mRNA levels of CNGA2 40 and 50%, respectively (P < 0.05). [Ca(2+)](i...

[1] During the Paleocene‐Eocene thermal maximum (PETM ∼55 Myr ago), prominent climatic and biogeochemical changes took place in the atmosphere, ocean, and on land. For example, deep‐sea temperatures rose by 5°C to 6°C, while sea surface temperatures at high latitudes increased by up to 9°C. In the sedimentary record, the onset of the PETM is marked by widespread dissolution of calcium carbonate...

Mitochondrial calcium handling and its relation with calcium released from sarcoplasmic reticulum (SR) in muscle tissue are subject of lively debate. In this study we aimed to clarify how the SR determines mitochondrial calcium handling using dCASQ-null mice which lack both isoforms of the major Ca(2+)-binding protein inside SR, calsequestrin. Mitochondrial free Ca(2+)-concentration ([Ca(2+)]mi...

AIMS The local concentration of extracellular Ca(2+) ([Ca(2+)]o) in bone microenvironment is accumulated during bone remodeling. In the present study we investigated whether elevating [Ca(2+)]o induced store-operated calcium entry (SOCE) in primary rat calvarial osteoblasts and further examined the contribution of elevating [Ca(2+)]o to osteoblastic proliferation. METHODS Cytosolic Ca(2+) con...

BACKGROUND Many targets of calcium signaling pathways are activated or inhibited by binding the Ca(2+)-liganded form of calmodulin (Ca(2+)-CaM). Here, we test the hypothesis that local Ca(2+)-CaM-regulated signaling processes can be selectively activated by local intracellular differences in free Ca(2+)-CaM concentration. RESULTS Energy-transfer confocal microscopy of a fluorescent biosensor ...