Venom of the Chilean Latrodectus mactans alters bovine spermatozoa calcium and function by blocking the TEA-sensitive K(+) current.

The morphology and size of spermatozoa make it difficult to study the functional properties of the plasma membrane, however, some studies have revealed the presence of a number of ion channels in this cell. We measured the calcium (Ca(++)) influx induced by depolarization of the plasma membrane and by venom isolated from the Chilean black widow spider (Latrodectus mactans), and functional changes in the presence of either high potassium or total venom. Our results indicate that the venom increased the Ca(++) influx, with an EC50 of 6.1 microg/mL and triggering the acrosome reaction in 43.26% of the cells. The application of potassium (10 mM K(+)) or total venom (10 microg/mL) did not affect the morphology or DNA stability of the sperm. The effects induced by high K(+) and venom suggest that direct blocking of K(+) currents alters the passive properties of the plasma membrane, leading to the entry of Ca(++). These results show the importance of functional changes induced by depolarizing the spermatozoa and by venom. This venom possesses one or more molecules that may be used as pharmacological tools for studies on spermatozoa and have potential applications in reproductive biotechnology.