VOLUME REGULATION OF SPERMATOZOAS BY QUININE-SENSITIVE CHANNELS

Bovine spermatozoa were shown to exhibit rapid regulatory volume decre ase (RVD) when exposed to hypotonic saline media. This quinine- and qu inidine-sensitive regulatory volume decrease was coincident with Kt re lease due to stretch-activation of inhibitor-specific presumptive K+ c hannels. The regulatory volume decrease response was much faster than a similar phenomenon observed in human peripheral blood lymphocytes. S tudies on volume changes in different electrolyte and nonelectrolyte m edia suggested that: (1) this inhibitor-specific channel could also be a nonspecific pore in the spermatozoal membrane for nonelectrolytes b elow 150 daltons; (2) subpopulations (of nearly equal size) of the spe rmatozoa differ in the expression of the pore; (3) capacitation abolis hes this distinction between subpopulations of spermatozoa; and (4) th e general case of RVD for other mammalian spermatozoa was also establi shed. (C) 1997 Wiley-Liss, Inc.