Schackmann R W, Christen R, Shapiro B M
Proc Natl Acad Sci U S A. 1981 Oct;78(10):6066-70. doi: 10.1073/pnas.78.10.6066.
The intracellular pH and membrane potential in sperm of the sea urchin Strongylocentrotus purpuratus were investigated by using fluorescent and radiolabeled probes. The weak bases [14C]methylamine, [14C]diethylamine, and 9-aminoacridine were concentrated within sperm 5-fold or greater. The weak acid [14C]dimethyloxazolidine-2,4-dione (DMO) was excluded from sperm. These data suggested that the apparent intracellular pH is acidic with respect to seawater (pH 8.0). Induction of the acrosome reaction caused efflux of the amines and uptake of DMO, consistent with an increase in apparent intracellular pH of 0.1-0.2 pH unit. The presence of an internally negative membrane potential was indicated by estimating the distribution of [3H]tetraphenylphosphonium (Ph4P+) and [14C]SCN-. From SCN- exclusion we estimated a value of about -30 mV for the nonmitochondrial membrane potential, whereas from Ph4P+ accumulation an apparent potential of -90 to -150 mV was demonstrated. The membrane potentials obtained with Ph4P+ and SCN- were dependent upon the external K+ concentration, with increasing K+ leading to depolarization. Induction of the acrosome reaction led to efflux of Ph4P+ and uptake of SCN- for an approximate depolarization of about 30 mV, primarily due to the collapse of the plasma membrane potential.
利用荧光和放射性标记探针，对紫海胆精子的细胞内pH值和膜电位进行了研究。弱碱[¹⁴C]甲胺、[¹⁴C]二乙胺和9-氨基吖啶在精子内的浓缩倍数达5倍或更高。弱酸[¹⁴C]二甲基恶唑烷-2,4-二酮（DMO）被精子排出。这些数据表明，相对于海水（pH 8.0），精子的表观细胞内pH呈酸性。顶体反应的诱导导致胺类外流和DMO摄取，这与表观细胞内pH升高0.1 - 0.2个pH单位一致。通过估计[³H]四苯基鏻（Ph4P⁺）和[¹⁴C]SCN⁻的分布，表明存在内部负膜电位。根据SCN⁻的排除情况，我们估计非线粒体膜电位约为 - 30 mV，而根据Ph4P⁺的积累情况，显示出 - 90至 - 150 mV的表观电位。用Ph4P⁺和SCN⁻获得的膜电位取决于外部K⁺浓度，K⁺浓度增加会导致去极化。顶体反应的诱导导致Ph4P⁺外流和SCN⁻摄取，使膜电位大约去极化30 mV，这主要是由于质膜电位的崩溃。
