Exogenous lysophosphatidylcholine increases non-selective cation current in guinea-pig ventricular myocytes

Whole cell, patch-clamp studies were performed to examine the effect of lysophosphatidylcholine (LPC) on the membrane current in guinea-pig ventricular myocytes. The addition of 10 μM LPC to the external solution 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 current with the reversal potential near 0 mV, indicating that the current passed through a Ca²⁺-permeable non-selective cation channel. The order of the cationic permeability calculated from the reversal potential of the current was Cs⁺ > K⁺ > NMG > Na⁺ > Ca²⁺. Cl⁻ did not pass through 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 pipette solution. In conclusion, LPC induces a Ca²⁺-permeable non-selective cation channel in guinea-pig ventricular myocytes. Received: 11 September 1995/Received after revision: 3 January 1996/Accepted: 12 February 1996