A low threshold calcium current recorded at physiological Ca concentrations in single frog atrial cells.
The presence of a low threshold calcium current (ICa,LT) besides the classical (high threshold) calcium current (ICa,HT) is investigated using the whole-cell patch-clamp technique (10) on Cs-loaded frog atrial cells at physiological Ca concentrations. ICa,LT, which inactivates within tens of milliseconds, gives rise to a shoulder in the negative part of the peak current-voltage curve. It is completely abolished by 40 microM Ni while ICa,HT is not modified. Cd (30 microM) decreases ICa,LT by about 50% while ICa,HT is completely abolished.
D000818:Animals; D016275:Atrial Function; D001464:Barium / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D004594:Electrophysiology; D006321:Heart / Q000502:physiology*; D007473:Ion Channels / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism; D011893:Rana esculenta
D007473:Ion Channels; D001464:Barium; D002118:Calcium