Caffeine activates a mechanosensitive Ca2+ channel in human red cells

Julio Cordero-Morales, P. J. Romero

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Caffeine is known to activate influx of both mono- and divalent cations in various cell types, suggesting that this xanthine opens non-selective cation channels at the plasma membrane. This possibility was investigated in human erythrocytes, studying the caffeine action on net Ca2+, Na+ and K+ movements in ATP-depleted cells. Whole populations and subpopulations of young and old erythrocytes were employed. Caffeine was tested in the presence of known mechanosensitive channel blockers (Gd3+, neomycin and amiloride) and ruthenium red as a possible inhibitor. Caffeine enhanced net cation fluxes in a concentration-dependent way. In whole populations, the Ca2+ entry elicited by 20 mM caffeine was fully suppressed by Gd3+ (5 μM), amiloride (250 μM) and ruthenium red (100 μM) and partially blocked by neomycin (100 μM). The above blockers also inhibited caffeine-dependent Na+ entry whilst showing antagonistic effects on the corresponding K+ efflux. These compounds fully suppressed hypotonically-induced (-35 mOsm/kg) Ca2+ influx at nearly the same concentrations completely blocking caffeine-stimulated Ca2+ entry. The effect of inhibitors on Ca2+ influx in young cells exceeded that in old cells at similar concentrations. The results clearly show that caffeine stimulates a stretch-activated Ca2+ channel in human red cells and that aged cells are less susceptible to mechanosensitive channel blockers.

Original languageEnglish (US)
Pages (from-to)189-200
Number of pages12
JournalCell Calcium
Volume31
Issue number5
DOIs
StatePublished - Jan 1 2002
Externally publishedYes

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Caffeine
Ruthenium Red
Neomycin
Amiloride
Cations
Erythrocytes
Monovalent Cations
Xanthine
Divalent Cations
Population
Adenosine Triphosphate
Cell Membrane

All Science Journal Classification (ASJC) codes

  • Physiology
  • Molecular Biology
  • Cell Biology

Cite this

Caffeine activates a mechanosensitive Ca2+ channel in human red cells. / Cordero-Morales, Julio; Romero, P. J.

In: Cell Calcium, Vol. 31, No. 5, 01.01.2002, p. 189-200.

Research output: Contribution to journalArticle

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