Regulatory volume decrease in Ehrlich ascites tumor cells is not mediated by a rise in intracellular calcium

Rebekah J. Thomas-Young, Thomas C. Smith, Charles Levinson

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Ehrlich ascites tumor cells suspended in hyposmotic solution initially swell and then shrink back towards normal volume, a process known as regulatory volume decrease (RVD), RVD is characterized by a specific loss of KCl, although the mechanism for this is currently unknown. The hypothesis that a rise in intracellular calcium ([Ca2+]i) activates calcium-sensitive ion conductances to initiate RVD was investigated. The results indicate that in the Ehrlich cell no rise in [Ca2+]i occurs when the extracellular osmolality is reduced from 300 mosM to 180 mosM. These findings were substantiated by the lack of sensitivity of RVD to the Ca2+-sensitive K+ channel blockers charybdotoxin (CTX) and nifedipine. In contrast, the ionophore ionomycin induced a cell shrinkage that was sensitive to CTX and nifedipine indicating that a rise in [Ca2+]i could play a role in cell volume reduction but that this occurred by a mechanism different from that observed in RVD. The conclusion from these experiments is that Ca2+ does not act as a second messenger for RVD in the Ehrlich cell.

Original languageEnglish (US)
Pages (from-to)81-86
Number of pages6
JournalBBA - Biomembranes
Volume1146
Issue number1
DOIs
StatePublished - Feb 23 1993
Externally publishedYes

Keywords

  • Ehrlich ascites tumor cell
  • Intracellular calcium
  • Tumor cell
  • Volume regulation

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

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