The voltage-dependent nonselective cation current in human red blood cells studied by means of whole-cell and nystatin-perforated patch-clamp techniques.
Human red blood cells (RBC) can be studied by means of whole-cell and nystatin-perforated patch-clamp techniques. In 85% of the whole-cell experiments (n=86) and 69% of the perforated-patch recordings (n=13), steps to positive potentials, from a holding potential of 0 mV, induced a slow-activating non-inactivating persistent outward current which reverted at about 0 mV. The current activation phase fitted well with a two-component exponential curve. Half-maximal conductance was reached at about 42 mV. Na+ and K+ carried this current, which was not affected by 20 nM charybdotoxin or 20 mM TEA, but was reduced following a partial substitution of extracellular Cl- by tartrate. This current has characteristics similar to the single-channel currents already described in RBC and may be involved in the rapid adaptations of these cells in the circulation.
Rodighiero
S
S
Institute of Human Physiology II, University of Milano, Via Mangiagalli, 32, I-20133 Milano, Italy.
De Simoni
A
A
Formenti
A
A
D002712:Chlorides / Q000494:pharmacology; D004912:Erythrocytes / Q000737:chemistry*; D006801:Humans; D007473:Ion Channels / Q000737:chemistry*; D008564:Membrane Potentials; D009761:Nystatin; D018408:Patch-Clamp Techniques
D002712:Chlorides; D007473:Ion Channels; C491712:non-selective cation channel protein, human; D009761:Nystatin