title: Dual regulation of the T-type Ca(2+) current by serum albumin and beta-estradiol in mammalian spermatogenic cells.
abstract: This study provides evidence for a novel mechanism of voltage-gated Ca(2+) channel regulation in mammalian spermatogenic cells by two agents that affect sperm capacitation and the acrosome reaction (AR). Patch-clamp experiments demonstrated that serum albumin induced an increase in Ca(2+) T current density in a concentration-dependent manner, and significant shifts in the voltage dependence of both steady-state activation and inactivation of the channels. These actions were not related to the ability of albumin to remove cholesterol from the membrane. In contrast, beta-estradiol significantly inhibited Ca(2+) channel activity in a concentration-dependent and essentially voltage-independent fashion. In mature sperm this dual regulation may influence capacitation and/or the AR.
authors.affiliation: Department of Genetics and Molecular Physiology, Institute of Biotechnology, UNAM, Avenida Universidad 2001, Cuernavaca, Mexico.
authors.forename: F
authors.initials: F
authors.lastname: Espinosa
authors.forename: I
authors.initials: I
authors.lastname: López-González
authors.forename: C
authors.initials: C
authors.lastname: Muñoz-Garay
authors.forename: R
authors.initials: R
authors.lastname: Felix
authors.forename: J L
authors.initials: JL
authors.lastname: De la Vega-Beltrán
authors.forename: G S
authors.initials: GS
authors.lastname: Kopf
authors.forename: P E
authors.initials: PE
authors.lastname: Visconti
authors.forename: A
authors.initials: A
authors.lastname: Darszon
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D020747:Calcium Channels, T-Type / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D017136:Ion Transport / Q000187:drug effects; D008297:Male; D018408:Patch-Clamp Techniques; D012709:Serum Albumin / Q000494:pharmacology*; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D020747:Calcium Channels, T-Type; D012709:Serum Albumin; D004958:Estradiol; D002118:Calcium