Mouse sperm membrane potential: changes induced by Ca2+

FEBS Letters

Darszon, Alberto¹  Espinosa, Felipe¹ 

[1] Depto. Genética y Fisiologia Molecular, Instituto de Biotecnologia, Universidad Nacional Autónoma de Mexico, Apdo. 510-3, Cuernavaca, Morelos 62271, México

关键词: Sperm membrane potential;    Ion channel;    Na-K ATPase;    Acrosome reaction;   

DOI  :  10.1016/0014-5793(95)00962-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Mouse sperm resting membrane potential (E _r) (−42±8.8 mV), determined with a potential sensitive dye, depended on extracellular K⁺ and, in the absence of extracellular Ca²⁺ ([Ca²⁺]_e), on external Na⁺ ([Na⁺]_e). Ca²⁺ addition (>5 μM) to sperm in Ca-free media induced a transient hyperpolarization (Ca-ith) which strongly depended on [Na⁺]_e and less on external Cl⁻ ([Cl⁻]_e). Cd²⁺ and Mn²⁺ (μM) mimicked the Ca²⁺ effect, but not Ba²⁺. The Ca-ith was partially inhibited by ouabain (74%, IC ₅₀ = 5.8 μM) and niflumic acid (38%, IC ₅₀ = 240 μM), indicating the participation of the Na-K ATPase and Cl⁻ channels. In Ca-free low-Na⁺ media, Ca²⁺ addition caused a depolarization sensitive to: nimodipine (25 μM), trifluoperazine (12.5 μM) and Mg²⁺ (1.2 mM), suggesting the participation of Ca²⁺ channels. Since some inhibitors of the sperm Ca-ith block the acrosome reaction (AR), both processes may share transport systems.

【 授权许可】

Unknown