Skip to Main content Skip to Navigation
Journal articles

Caffeine-induced current in embryonic heart cells: time course and voltage dependence

Abstract : Abrupt exposure of 90- to 130-micron diameter chick embryonic myocardial cell aggregates to 10 mM caffeine has been shown to induce a transient inward current. In the present study, we recorded a similar current in small cell clusters (less than 10 cells) in which access of caffeine to each of the cells was rapid. The resulting inward current consisted of a single peak, which decayed exponentially (predominant time constant 335 +/- 130 ms at -40 mV) and had a peak amplitude of up to 15.5 microA/cm2. The caffeine-induced current persisted when the slow inward current was abolished by a 30-s pretreatment with 2 microM D 600 and could be observed at potentials where the fast sodium channels were fully inactivated. The current-voltage relation of the caffeine response was linear between -110 and -40 mV, giving an extrapolated voltage intercept of +12 mV. However, the inward current did not diminish or reverse with further depolarization. A substantial inward current occurred at potentials up to +60 mV, which is more positive than the reversal potential of the tetrodotoxin-sensitive inward current. We conclude that the caffeine-induced current is mediated in part by electrogenic Na+-Ca2+ exchange.
Complete list of metadata
Contributor : RODOLPHE FISCHMEISTER Connect in order to contact the contributor
Submitted on : Thursday, March 24, 2022 - 4:57:34 PM
Last modification on : Saturday, March 26, 2022 - 3:57:30 AM
Long-term archiving on: : Saturday, June 25, 2022 - 7:49:09 PM


Files produced by the author(s)



William Clusin, Rodolphe Fischmeister, Robert Dehaan. Caffeine-induced current in embryonic heart cells: time course and voltage dependence. American Journal of Physiology, American Physiological Society, 1983, 245 (3), pp.H528-32. ⟨10.1152/ajpheart.1983.245.3.H528⟩. ⟨hal-03618987⟩



Record views


Files downloads