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Activation of calcium-ion (Ca2+) channels on the plasma membrane and on intracellular Ca2+ stores, such as the endoplasmic reticulum, generates local transient increases in the cytosolic Ca2+ concentration that induce Ca2+ uptake by neighbouring mitochondria. Here, by using mitochondrially targeted aequorin proteins with different Ca2+ affinities, we show(More)
Potassium-stimulated catecholamine release from superfused bovine adrenal chromaffin cells (70 mM K+ in the presence of 2 mM Ca2+ for 10 s, applied at 5-min intervals) was inhibited by the dihydropyridine furnidipine (3 microM) by 50%. omega-Conotoxin MVIIC (CTx-MVIIC, 3 microM) also reduced the secretory response by about half. Combined CTx-MVIIC plus(More)
1. The effects of externally applied micromolar concentrations of adenosine 5'-triphosphate (ATP) on Ca2+ currents (ICa) were studied in whole-cell clamped adrenaline-secreting chromaffin cells. 2. Ca2+ currents in chromaffin cells activated at about -40 mV, reached a maximum at 0 mV and had an apparent reversal potential at +50 to +60 mV, indicating the(More)
The presence and physiological role of Ca 2 ϩ-induced Ca 2 ϩ release (CICR) in nonmuscle excitable cells has been investigated only indirectly through measurements of cytosolic [Ca 2 ϩ ] ([Ca 2 ϩ ] c). Using targeted aequorin, we have directly monitored [Ca 2 ϩ ] changes inside the ER ([Ca 2 ϩ ] ER) in bovine adrenal chromaffin cells. Ca 2 ϩ entry induced(More)
Catecholamine release from bovine adrenal medulla chromaffin cells superfused with a Krebs-N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid solution was monitored on-line with an electrochemical detector. Caffeine (10 mM) progressively depressed the magnitude of secretory responses to depolarizing pulses of 70 mM K+ and 2 mM Ca2+ (70 K+/2 Ca2+) in cells(More)
The effects of several physiological agonists on the cytosolic Ca2+ concentration ([Ca2+]i) of immunnocytochemically identified single adrenergic and noradrenergic bovine chromaffin cells were compared. No differences were observed in the responses to stimulation by high-K+ solutions with or without BAY K 8644, suggesting that the density and properties of(More)
This study was carried out to characterize the set of voltage-dependent Ca2+ channel subtypes expressed by mouse adrenal chromaffin cells superfused with solutions containing low (2 mM) or high (10 mM) Ba2+ concentrations. Using 50-ms test pulses at 0 mV from a holding potential of -80 mV, averaged peak current in 10 mM Ba2+ was around 1 nA, and in 2 mM(More)
This study was undertaken to reassess the set of voltage-dependent Ca2+ channel subtypes expressed by bovine adrenal chromaffin cells maintained in primary cultures. Previous views on the pharmacology of such channels had to be revised in the light of the novel data which arose from the use in this study of low and high micromolar concentrations of(More)
At a given cytosolic domain of a chromaffin cell, the rate and amplitude of the Ca2+ concentration ([Ca2+]c) depends on at least four efficient regulatory systems: 1) plasmalemmal calcium channels, 2) endoplasmic reticulum, 3) mitochondria, and 4) chromaffin vesicles. Different mammalian species express different levels of the L, N, P/Q, and R subtypes of(More)
ITH33/IQM9.21 is a novel compound belonging to a family of glutamic acid derivatives, synthesized under the hypothesis implying that multitarget ligands may provide more efficient neuroprotection than single-targeted compounds. In rat hippocampal slices, oxygen plus glucose deprivation followed by re-oxygenation (OGD/Reox) elicited 42% cell death. At 1 μM,(More)