Cannabinoid receptor activates spermatozoa

Biologists have detected a cannabinoid receptor in spermatozoa. Endogenous cannabinoids that occur in both the male and the female genital tract activate the spermatozoa: they trigger the so-called acrosome reaction, during which the spermatozoon releases digestive enzymes and loses the cap on the anterior half of its head. Without this reaction, spermatozoa cannot penetrate the ovum.