Adenosine Stimulates Human Sperm Motility via A2 Receptors

Abstract

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.

Specific Repertoire of Olfactory Receptor Genes in the Male Germ Cells of Several Mammalian Species

“…The strong expression observed for some of the rodent testicular cDNAs in the olfactory directly in the control of sperm motility, but various ligands acting on G protein-coupled receptors have mucosa was unexpected. In our previous RPA analysis of three dog testis clones, no expression or a weak ex-been shown to stimulate sperm motility (Shen et al, 1992;Vinson et al, 1995). In addition, the presence in pression was found in the olfactory mucosa, in contrast with the strong testicular expression (Vanderhaeghen mammalian sperm cells of a variety of G protein a subunits has been demonstrated (Ward and Kopf, 1993;.…”

Adenosine and Catecholamine Agonists Speed the Flagellar Beat of Mammalian Sperm by a Non-Receptor-Mediated Mechanism1

“…One possibility is that the agonists act at conventional receptors on the plasma membrane that somehow link to the SACY enzyme. Some of these receptors are reportedly found in sperm [18][19][20][21][22], but their role in adenosine and catecholamine signaling in sperm has not been conclusively demonstrated.…”

Signaling Pathways for Modulation of Mouse Sperm Motility by Adenosine and Catecholamine Agonists1

“…For example, adenosine and analogs were reported to variously increase the percentage of motile cells, intracellular cAMP content, protein tyrosine phosphorylation, capacitation, or fertilizing ability of mouse [13][14][15], bull [16], and human sperm [17][18][19][20]. Actions of catecholamines on sperm capacitation have been less studied.…”