Involvement of calcium in the caffeine stimulation of human sperm motility.
The shape of the concentration-response curve and the amplitude of maximal motility increase for the stimulatory effect of caffeine on human sperm motility were similar to those of EGTA, a calcium chelator, and lanthanum chloride, a calcium entry blocker. On the other hand, the maximal motility stimulation induced by dibutyryl cyclic AMP was similar to that induced by trifluoperazine, a calmodulin antagonist. The antagonism of A23187 on the motility-stimulating effect of EGTA and caffeine was competitive in nature, while that on cyclic AMP was non-competitive. We proposed that there could be two mechanisms for caffeine to stimulate sperm motility: at higher concentrations, caffeine modified calcium translocation; at lower concentrations, caffeine increased cyclic AMP level. The importance of calcium in the regulation of human sperm motility was reconfirmed in this study.
Hong
C Y
CY
Chiang
B N
BN
Wu
P
P
Wei
Y H
YH
Fong
J C
JC
D003994:Bucladesine / Q000494:pharmacology; D002110:Caffeine / Q000494:pharmacology*; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology; D006801:Humans; D008297:Male; D013081:Sperm Motility / Q000187:drug effects*
D000001:Calcimycin; D002110:Caffeine; D004533:Egtazic Acid; D003994:Bucladesine; D002118:Calcium