Na⁺/Ca²⁺ exchanger type 1 functions as a “brake” of hyperactivation in hamster sperm.

Mammalian sperm including human have to undergo several physiological and biochemical changes, collectively called capacitation, to be fertilization-competent. Capacitated sperm show specialized vigorous motility called hyperactivation. Hyperactivation is necessary to progress in the viscous oviductal environment.