Adenosine stimulates human sperm motility via A2 receptors.
The effects of adenosine and its analogues on human sperm motility were studied using a transmembrane migration method. Specific binding sites for adenosine in human sperm were also investigated. Adenosine and 5'-N-ethylcarboxamidoadenosine (NECA) stimulated human sperm motility with similar efficacies and the maximal amplitudes of motility increases were both about 70%. 3,7-Dimethyl-1-propargylxanthine (DMPX), a potent A2 antagonist, competitively antagonized NECA-induced motility stimulation. Successively higher concentrations of DMPX shifted the dose-response curve of NECA to the right in a nearly parallel fashion. Dipyridamole, an inhibitor of adenosine uptake, does not reduce the ability of adenosine to stimulate human sperm motility. In radioligand-binding studies, adenosine A1 selective analogues, cyclopentyl-1,3-dipropylxanthine and 1-methyl-2-phenylethyl adenosine, have little competitive effect on [3H]NECA binding in human sperm membrane. These results provide evidence that adenosine enhances human sperm motility via adenosine A2 receptors on the surface of sperm membranes.
Shen
M R
MR
Graduate Institute of Medicine, Kaohsiung Medical College, Taiwan, R.O.C.
Linden
J
J
Chiang
P H
PH
Chen
S S
SS
Wu
S N
SN
D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology*; D019830:Adenosine-5'-(N-ethylcarboxamide); D001665:Binding Sites; D004176:Dipyridamole / Q000494:pharmacology; D006801:Humans; D008297:Male; D011869:Radioligand Assay; D018047:Receptors, Purinergic P1 / Q000187:drug effects*; D013081:Sperm Motility / Q000187:drug effects*; D013805:Theobromine / Q000031:analogs & derivatives* / Q000494:pharmacology
D018047:Receptors, Purinergic P1; D019830:Adenosine-5'-(N-ethylcarboxamide); C057837:3,7-dimethyl-1-propargylxanthine; D004176:Dipyridamole; D000241:Adenosine; D013805:Theobromine