Influence of histamine and H1-receptor antagonists on ejaculated human spermatozoa: role of intrasperm Ca2+.

Histamine reduced sperm viability in a dose- and time-dependent manner, accompanied by rise in intrasperm Ca2+. Further, 2',4'-dichlorobenzamil hydrochloride (DBZ), a Na+-Ca2+ exchange inhibitor, known to elevate intrasperm Ca2+, potentiated both, elevation of intrasperm Ca2+ and spermicidal action of histamine. Pretreatment of sperm with very low doses of H1-receptor antagonists (chlorpheniramine, promethazine or diphenhydramine) prevented the histamine-induced elevation of intrasperm Ca2+ as well as its spermicidal action. However, pretreatment with famotidine, a H2-receptor antagonist did not produce such a protective action. The results strongly suggest that histamine elicits its spermicidal action via H1-receptors present on sperm cells.