EXOGENOUS LYSOPHOSPHATIDYLCHOLINE INCREASES NONSELECTIVE CATION CURRENT IN GUINEA-PIG VENTRICULAR MYOCYTES

Whole cell, patch-clamp studies were performed to examine the effect o f lysophosphatidylcholine (LPC) on the membrane current in guinea-pig ventricular myocytes. The addition of 10 mu M LPC to the external solu tion induced a membrane current which had a reversal potential of 0 mV . When Na+, the main cation in the external solution, was replaced by either K+, N-methyl-D-glucamine (NMG) or 90 mM Ca2+, LPC induced a cur rent with the reversal potential near 0 mV, indicating that the curren t passed through a Ca2+-permeable non-selective cation channel. The or der of the cationic permeability calculated from the reversal potentia l of the current was Cs+ > K+ > NMG > Na+ > Ca2+. Cl- did not pass thr ough the LPC-induced channel. The LPC-induced current was not blocked by Gd3+ in the external solution, nor by the absence of Ca2+ in the pi pette solution. In conclusion, LPC induces a Ca2+-permeable non-select ive cation channel in guinea-pig ventricular myocytes.