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Expression and differential cell distribution of low‐threshold Ca 2+ channels in mammalian male germ cells and sperm
Author(s) -
Treviño Claudia L,
Felix Ricardo,
Castellano Laura E,
Gutiérrez Carolina,
Rodrı́guez Delany,
Pacheco Judith,
López-González Ignacio,
Gomora Juan Carlos,
Tsutsumi Victor,
Hernández-Cruz Arturo,
Fiordelisio Tatiana,
Scaling Allison L,
Darszon Alberto
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(04)00257-1
Subject(s) - sperm , acrosome reaction , biology , motility , mibefradil , sperm motility , microbiology and biotechnology , patch clamp , voltage dependent calcium channel , chemistry , calcium , biochemistry , genetics , receptor , organic chemistry
Numerous sperm functions including the acrosome reaction (AR) are associated with Ca 2+ influx through voltage‐gated Ca 2+ (Ca V ) channels. Although the electrophysiological characterization of Ca 2+ currents in mature sperm has proven difficult, functional studies have revealed the presence of low‐threshold (Ca V 3) channels in spermatogenic cells. However, the molecular identity of these proteins remains undefined. Here, we identified by reverse transcription polymerase chain reaction the expression of Ca V 3.3 mRNA in mouse male germ cells, an isoform not previously described in these cells. Immunoconfocal microscopy revealed the presence of the three Ca V 3 channel isoforms in mouse spermatogenic cells. In mature mouse sperm only Ca V 3.1 and Ca V 3.2 were detected in the head, suggesting its participation in the AR. Ca V 3.1 and Ca V 3.3 were found in the principal and the midpiece of the flagella. All Ca V 3 channels are also present in human sperm, but only to a minor extent in the head. These findings were corroborated by immunogold transmission electron microscopy. Tail localization of Ca V 3 channels suggested they may participate in motility, however, mibefradil and gossypol concentrations that inhibit Ca V 3 channels did not significantly affect human sperm motility. Only higher mibefradil doses that can block high‐threshold (HVA) Ca V channels caused small but significant motility alterations. Antibodies to HVA channels detected Ca V 1.3 and Ca V 2.3 in human sperm flagella.