Effect of Tetraethylammonium Chloride on the Electrical Characteristics of Cardiomyocytes Studied by Atomic Force Microscopy

In this paper, the effect of tetraethylammonium chloride (TEAC) on the electrical characteristics of cardiomyocytes was studied by an atomic force microscope (AFM). The average membrane potential (MP) of cardiomyocytes in the untreated group was 16.35 ± 2.91 mV, while the average MP of cardiomyocytes was 12.54 ± 2.53, 7.28 ± 1.57, and 3.23 ± 0.45 mV after adding 20 mmol/L of TEAC for 10, 20, and 40 min, respectively. When the cell membrane was punctured, the duration of the ion current was about 1.12, 0.83, 0.65, and 0.41 s. In comparison with the untreated group, the effective refractory period (ERP) of cardiomyocytes increased from 0.22 ± 0.05 s to 0.47 ± 0.09, 0.63 ± 0.12, and 0.76 ± 0.2 s, respectively. With the TEAC concentration from 0 to 20 mmol/L, the average MP of cardiomyocytes decreased from 19.57 ± 2.23 to 3.43 ± 0.63 mV, and the ERP of cardiomyocytes increased from 0.22 ± 0.08 to 0.73 ± 0.15 s. The results showed that with the prolongation of the TEAC action time and the increase of concentration, the MP of cardiomyocytes decreased along with increases in the action potential duration (APD) and ERP. This study revealed the effect of the TEAC on the cardiomyocytes from the perspective of biophysics. This is helpful for a more comprehensive understanding of the interaction action between the TEAC and cardiomyocytes and further clarifies the action of the TEAC effects on the inhibited ion channels and ion permeability. The research is especially important for pharmacological research, including the screening of targeted drugs and the drug-targeted location of ion channels.