Hyperactivated Motility in Sperm

Abstract

Hyperactivation is a movement pattern seen in sperm at the site and time of fertilization in mammals. It may be critical to the success of fertilization, because it enhances the ability of sperm to detach from the wall of the oviduct, to move around in the labyrinthine lumen of the oviduct, to penetrate mucous substances and, finally, to penetrate the zona pellucida of the oocyte. The movement of hyperactivated sperm appears different under different physical conditions and in different species, but basically it involves an increase in flagellar bend amplitude and, usually, beat asymmetry. Presumably, a signal or signals exist in the oviduct to initiate hyperactivation at the appropriate time; however, none has yet been identified with certainty. While the signal transduction cascade regulating hyperactivation remains to be completely described, it is clear that calcium ions interact with the axoneme of the flagellum to switch on hyperactivation. Although hyperactivation often occurs during the process of capacitation, the two events are regulated by somewhat different pathways.

A polycystin-1 controls postcopulatory reproductive selection in mice

“…It is not known whether these functional changes were regulated coordinately or independently. Previously, media conditions or pharmacological treatments dissected the development of hyperactivated sperm motility in vitro from such component events of capacitation as the increased frequency of spontaneous (that is, ZP agonistindependent) acrosome reaction (43,44) or the enhanced tyrosine protein phosphorylation that accompanies capacitation (45,46). Similarly, hyperactivation depends on the function of the Catsper family of cation channels and of Pcma4, the Ca 2ϩ -conducting ATPase (47)(48)(49).…”

Relationship Between Standard Semen Parameters, Calcium, Cholesterol Contents, and Mitochondrial Activity in Ejaculated Spermatozoa From Fertile and Infertile Males

“…Concerning Ca 2+ concentrations undoubtedly this cation is directly linked with sperm metabolism, concretely with hyperactivation process taking place in the oocyte fertilization (10).…”

“…Nevertheless, hyperactivation, a process that assists sperm cells in penetrating the cumulus matrix directly depends on it. Moreover, after the acrosome reaction, the zona pellucida is trespassed by raising intracellular Ca 2+ concentrations in sperm (10).…”

Activation of GABAAReceptor/Cl−Channel and Capacitation in Rat Spermatozoa: HCO3−and Cl−are Essential

“…It has been shown that Na þ , K þ , Ca þ , HCO 3 À , BSA and energy substrates are important for hyperactivated sperm motility [Burkman et al 1984;Fraser 1983;Hyne et al 1985;Suarez 1996;Yanagimachi 1994]. The reason for the apparent conflict may reflect, at least in part, the use of different sperm capacitating media and the fact that different studies measured hyperactivation by different techniques which measure different stages of capacitation.…”