This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Minelli, A. Articles by Fredholm, B. B. Search for Related Content PubMed PubMed Citation Articles by Minelli, A. Articles by Fredholm, B. B.

Involvement of A₁ Adenosine Receptors in the Acquisition of Fertilizing Capacity

ROBERTA MANNUCCI

BJöRN JOHANSSON

BERTIL B. FREDHOLM

From the ^* Dipartimento di Scienze Biochimiche e Biotecnologie Molecolari, Sezione Biochimica Cellulare, Perugia, Italy; Dipartimento di Medicina Interna e Scienze Oncologiche, Policlinico Monteluce Perugia, Italy; and Department of Physiology and Pharmacology, Section of Molecular Neuropharmacology, Karolinska Institutet, Stockholm, Sweden.

Correspondence to: Dr Alba Minelli, Dipartimento Scienze Biochimiche e Biotecnologie Molecolari, Sezione Biochimica Cellulare, Via del Giochetto, 06123 Perugia, Italy.

Ejaculated mammalian spermatozoa acquire competence to fertilize oocytes by a two-step process: capacitation followed by acrosome reaction. The biochemical and biophysical modifications occurring in vivo in the female reproductive tract can be reproduced in vitro, and previous studies have suggested a capacitative role for adenosine A₁ receptor (A₁R). Mice with a targeted disruption of the Adora 1 gene (A₁R–/– mice) provide a useful model for better understanding the role of the A₁R in fertility. Murine spermatozoa express A₁R in the head, neck, midpiece region, and tail. The number of capacitated spermatozoa incubated in human tubal fluid was significantly reduced in A₁R–/– compared with A₁R+/+ and A₁R+/– spermatozoa. The difference between A₁ R+/+ and A₁R–/– mouse spermatozoa was mainly in the time necessary to reach the maximum percentage of capacitation. A₁R+/+ murine sperm obtained the full state of capacitation within 90 minutes whereas A₁R–/– sperm required 240 minutes. Caffeine, a known antagonist of A₁ and A_2A adenosine receptors, lowered the number of capacitated sperm and affected the time of capacitation in a dose-dependent manner, mimicking the effects of the lack of A₁ receptors. Although number, motility, and viability of A₁R–/– murine sperm was not significantly different from A₁R+/+ mouse spermatozoa, a significant reduction of the number of pups produced by A₁R–/– male mice suggests that A₁ receptors must be fully operative to accomplish the optimal degree of capacitation and thereby fertilization.

     Key words: A₁ adenosine receptors KO mice, A₁ adenosine receptors mouse sperm localization, capacitation, caffeine, fertility

This article has been cited by other articles:

				S. M. Schuh, A. E. Carlson, G. S. McKnight, M. Conti, B. Hille, and D. F. Babcock Signaling Pathways for Modulation of Mouse Sperm Motility by Adenosine and Catecholamine Agonists Biol Reprod, March 1, 2006; 74(3): 492 - 500. [Abstract] [Full Text] [PDF]

				L. Cotton, G. M. Gibbs, L. G. Sanchez-Partida, J. R. Morrison, D. M. de Kretser, and M. K. O'Bryan FGFR-1 signaling is involved in spermiogenesis and sperm capacitation J. Cell Sci., January 1, 2006; 119(1): 75 - 84. [Abstract] [Full Text] [PDF]

				A. S. Georgiou, E. Sostaric, C. H. Wong, A. P. L. Snijders, P. C. Wright, H. D. Moore, and A. Fazeli Gametes Alter the Oviductal Secretory Proteome Mol. Cell. Proteomics, November 1, 2005; 4(11): 1785 - 1796. [Abstract] [Full Text] [PDF]