Mechanism involve in amphibian sperm motility activation.

EMMA D. O’BRIEN ECHEVERRÍA, DARÍO KRAPF , PABLO E. VISCONTI AND SILVIA E. ARRANZ

Okinawa, Japón

Simposio; 11th International Symposium on Spermatology; 2010

In animals with external fertilization like some amphibians, spermatozoa are stored in a quiescent state in the testis, but after spawning, dilution into water triggers activation of motility. The initiation of sperm motility is regulated by external factors, including the change of osmolality or ion concentration. Also there are evidences suggesting that a network of kinases and phosphatases regulates sperm flagellar movement. The aim of the present work was to study the effect of the external factors (osmolality, ion concentration) on the amphibian anura Bufo arenarum sperm motility and the signaling pathway involved in this mechanism. Sperm were immotile in artificial seminal plasma (292 mOsm/Kg) and a fifty percentage of the sperm became motile at osmolarities below 100mOsm/Kg. The percentage of progressive movement of sperm preincubated in a hyposmotic solution containing Na+ was significantly higher that in a medium with K+ instead of Na+. In addition, sperm became immotile in a hypotonic solution without Ca2+. Using specific antibodies we detected an increase in PKA phosphorylation and a decrease of PKC phosphorylation during the motility activation. Finally, using a pharmacological approach (inhibitors and activators of both kinases) we showed that both kinases play a key role in the regulation of the toad sperm motility triggered by the osmotic shock.