Transient rise in intracellular calcium produces a long-lasting increase in plasma membrane calcium pump activity in rat sensory neurons

William J. Pottorf, Stanley A Thayer

Research output: Contribution to journalArticle

38 Scopus citations

Abstract

The plasma membrane Ca2+ ATPase (PMCA) plays a major role in clearing Ca2+ from the neuronal cytoplasm. Calmodulin stimulates PMCA activity and for some isoforms this activation persists following clearance of Ca2+ owing to the slow dissociation of calmodulin. We tested the hypothesis that PMCA-mediated Ca2+ efflux from rat dorsal root ganglion (DRG) neurons in culture would remain stimulated following increases in intracellular Ca2+ concentration ([Ca2+]i). PMCA-mediated Ca2+ extrusion was,recorded following brief trains of action potentials using indo-l-based photometry in the presence of cyclopiazonic acid. A priming stimulus that increased [Ca2+]i to 506 ± 28 nM (>15 min) increased the rate constant for [Ca2+]i recovery by 47 ± 3%. Ca2+ clearance from subsequent test stimuli remained accelerated for up to an hour despite removal of the priming stimulus and a return to basal [Ca2+]i. The acceleration depended on the magnitude and duration of the priming [Ca2+]i increase, but was independent of the source of Ca2+. Increases in [Ca2+]i evoked by prolonged depolarization, sustained trains of action potentials or activation of vanilloid receptors all accelerated Ca2+ efflux. We conclude that PMCA-mediated Ca2+ efflux in DRG neurons is a dynamic process in which intense stimuli prime the pump for the next Ca2+ challenge.

Original languageEnglish (US)
Pages (from-to)1002-1008
Number of pages7
JournalJournal of Neurochemistry
Volume83
Issue number4
DOIs
StatePublished - Nov 2002

Keywords

  • Calcium pump
  • Calmodulin
  • Dorsal root ganglion
  • Plasma membrane calcium ATPase

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