MEASUREMENT OF INTRACELLULAR CALCIUM LEVELS OF HUMAN SPERMATOZOA ACROSOME-REACTED BY ELECTROPERMEABILIZATION

Human spermatozoa readily undergo in vitro capacitation and the acroso me reaction when exposed to a single, brief, high-voltage electric pul se in a medium containing calcium. Using the fluorescent calcium indic ator, Fura-2, the changes in the intracellular calcium concentration o f human sperm following exposure to voltages in the range of 200-2000 V cm(-1) were measured. The induction of the acrosome reaction by the electropermeabilization pulse was also monitored. In comparison, chang es in calcium uptake during a standard capacitation procedure in which sperm samples were incubated for 7 h were analyzed. At hourly interva ls, acrosome reaction induction and intracellular calcium uptake were measured. The results indicate that electropermeabilization rapidly an d efficiently produces high populations of acrosome-reacted sperm and a corresponding and associated increase in the intracellular calcium c oncentration.