MEMBRANE-STABILIZING AND CALCIUM-BLOCKING AGENTS AFFECT ARBACIA SPERM MOTILITY

¹ Department of Physiology, Medical College of Ohio, Toledo, OH 43699, and Marine Biological Laboratory, Woods Hole, MA 02543

The speed and duration of progressive motility of Arbacia sperm cells depend on the calcium content of the suspension medium. Suspended in filtered sea water (FSW) the spermatozoa undergo a progressive decline in motility (after an initial burst of activity) and cease forward movement within 30-40 min. When sperm are diluted in chemically defined artificial sea water (MBL-ASW), motility rose to about 160% of the control rate in 30 min and then gradually returned to the initial control level where it persisted for at least 40 min more. Procaine, propranolol, ouabain, and quinidine, tested singly or in combination, affected sperm motility in both time- and concentration-dependent fashion.

Procaine at 10 and 100 µM/l in MBL-ASW caused more than a doubling in motility over the control rate, while in FSW both these concentrations were inhibitory. In FSW, quinidine had relatively little effect, while propranolol was slightly stimulatory at 10^-6 M and inhibitory at 0.1 and 1.0 x 10^-3 M. In combination, propranolol and quinidine can cause a sharp rise in motility. Ouabain increased motility dramatically in MBL-ASW suspensions. The effects of some of the drugs depend on the ability to displace calcium from binding sites in sperm cell membranes; ouabain appears to interface with Ca efflux.