Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.13.12.5 (aequorin)
 1,451 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Ca(2+)-sensitive photoprotein aequorin was used to monitor changes in intracellular [Ca2+] within cultured cells with characteristics of vascular smooth muscle. Two cell lines were investigated: they were A10 cells, which are transformed cells originally derived from rat aorta, and BC3H1 cells obtained from mouse brain neoplasm. Transient increases in intracellular [Ca2+] were induced following exposure to two different volatile anaesthetics (halothane and isoflurane) and various vasoactive substances (acetylcholine, endothelin, histamine, serotonin and vasopressin). The amplitude of the transients induced by isoflurane were more dependent on the presence of extracellular Ca2+ than those induced by halothane, thus the modes and/or locations of action of these two anesthetics are somewhat different. The response of the two cell lines to the vasoactive substances are unique. Receptor activated changes in [Ca2+]i by various agonists were diminished in the presence and absence of either anesthetic. These data suggest that, although the receptor populations within each cell line were slightly different, the prior application of a volatile anesthetic in a clinically-relevant dose induced a transient increase in [Ca2+]i that could subsequently diminish agonist responses.
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PMID:The effects of halothane and isoflurane on intracellular Ca2+ regulation in cultured cells with characteristics of vascular smooth muscle. 142 31

The kinetics of agonist-induced increases in cytosolic free Ca2+ have been measured in single A10 vascular smooth muscle cells and rat hepatocytes using fluorescent videomicroscopy with fura-2 as a Ca2+ indicator. At high agonist concentrations there was no difference in the kinetics of the Ca2+ transient measured in vasopressin-stimulated single A10 cells or in cell populations. However, stimulation of single A10 cells with concentrations of vasopressin below 0.5 nM produced characteristic Ca2+ transients composed of two distinct peaks. The two peaks appeared to represent a temporal separation between release of intracellular Ca2+ and influx of extracellular Ca2+. The double transient was not observed in single rat hepatocytes stimulated with low concentrations of vasopressin or phenylephrine. In both A10 cells and hepatocytes, the initial rate of increase in Ca2+ concentrations in response to submaximal agonist concentrations was faster in single cells than in cell populations. This difference was due to asynchrony of the cellular response, where there was a latent period of variable length before onset of a rapid increase in Ca2+ concentration. The duration of the latent period was dependent on the agonist concentration, higher concentrations of agonist giving a reduced latent period. The hormone-stimulated Ca2+ transient measured in single hepatocytes with fura-2 was different from the series of transient spikes as previously reported using aequorin as the Ca2+ indicator, suggesting that fura-2 and aequorin may report different aspects of the Ca2+ response in stimulated cells. Collectively, these results demonstrate that measurement of Ca2+ transients in single cells provide novel information concerning the nature of the Ca2+ transient that is not apparent from studies with cell populations.
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PMID:Novel kinetics of single cell Ca2+ transients in stimulated hepatocytes and A10 cells measured using fura-2 and fluorescent videomicroscopy. 335 Aug 5