Katp Channels in Mouse Spermatogenic Cells and Sperm, and Their Role in Capacitation.
From: Department of Developmental Genetics and Molecular Physiology, Institute of Biotechnology, UNAM, Cuernavaca, Mexico.
Developmental biology
- Publish Date: Jan 2006
- ISSN: 0012-1606
- Volume: 289
- Issue: 2
- Pages: 395-405
- Medium: Print
- Language: English
- Citation (JAMA): Acevedo Juan José, Mendoza-Lujambio Irene, de la Vega-Beltrán José Luis, et al. Katp Channels in Mouse Spermatogenic Cells and Sperm, and Their Role in Capacitation.. Dev. Biol. Jan 2006;289:395-405
Abstract
Mammalian sperm must undergo a series of physiological changes after leaving the testis to become competent for fertilization. These changes, collectively known as capacitation, occur in the female reproductive tract where the sperm plasma membrane is modified in terms of its components and ionic permeability. Among other events, mouse sperm capacitation leads to an increase in the intracellular Ca(2+) and pH as well as to a hyperpolarization of the membrane potential. It is well known that ion channels play a crucial role in these events, though the molecular identity of the particular channels involved in capacitation is poorly defined. In the present work, we report the identification and potential functional role of K(ATP) channels in mouse spermatogenic cells and sperm. By using whole-cell patch clamp recordings in mouse spermatogenic cells, we found K(+) inwardly rectifying (K(ir)) currents that are sensitive to Ba(2+), glucose and the sulfonylureas (tolbutamide and glibenclamide) that block K(ATP) channels. The presence of these channels was confirmed using inhibitors of the ATP synthesis and K(ATP) channel activators. Furthermore, RT-PCR assays allowed us to detect transcripts for the K(ATP) subunits SUR1, SUR2, K(ir)6.1 and K(ir)6.2 in total RNA from elongated spermatids. In addition, immunoconfocal microscopy revealed the presence of these K(ATP) subunits in mouse spermatogenic cells and sperm. Notably, incubation of sperm with tolbutamide during capacitation abolished hyperpolarization and significantly decreased the percentage of AR in a dose-dependent fashion. Together, our results provide evidence for the presence of K(ATP) channels in mouse spermatogenic cells and sperm and disclose the contribution of these channels to the capacitation-associated hyperpolarization.
Mesh Headings (Keywords): ATP-Binding Cassette Transporters, Adenosine Triphosphate, Animals, Barium, Diazoxide, Dose-Response Relationship, Drug, Glyburide, Male, Membrane Potentials, Mice, Microscopy, Confocal, Multidrug Resistance-Associated Proteins, Pinacidil, Potassium Channels, Inwardly Rectifying, RNA, Messenger, Sperm Capacitation, Spermatogenesis, Spermatozoa, Time Factors, Tolbutamide
Check for Full Text / PubMed Unique Identifier (PMID): 16343479
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