Alteration of membrane electrical activity in rat myocardial cells following selective laser microbeam irradiation.

Laser microirradiation of neonatal rat (1 to 2-day-old) ventricular cells in tissue culture results in overt changes in contractility. The intracellular study of their ongoing electrical activity prior to, during, and after laser microirradiation demonstrates that definite membrane alteration occurs concomitantly with induced contractile responses. Although all ventricular cells are depolarized by laser microirradiation, the ultimate response elicited seems to differ according to the type of myocardial cell impaled. Typical fibrillation potentials were induced mainly in pacemaker cells.