Goudeau H, Goudeau M, Guibourt N
Laboratoire de Biologie et Physiologie Cellulaires Marines, Université de Nice-Sophia Antipolis, France.
Dev Biol. 1992 Oct;153(2):227-41. doi: 10.1016/0012-1606(92)90108-s.
The fertilization potential in Phallusia mammillata consisted of an initial rapid depolarization. This initial sperm-triggered depolarization was followed by a phase of membrane depolarization which was of either long or short duration, depending on the eggs. When of long duration, the phase of membrane depolarization was divided into two periods: the first one began with a plateau (Em = +20.2 +/- 1.1 mV; duration = 1.7 +/- 0.14 min) which was followed by a series of membrane potential oscillations (n = 3.1 +/- 0.25) lasting 2.4 +/- 0.2 min. The second period also began as a plateau (Em = approximately 0 mV; duration = 3.40 +/- 0.20 min) which was followed by a series of oscillations (n = 11.5 +/- 0.5) lasting 11.8 +/- 0.6 min, followed by a membrane repolarization. The second series of oscillations often continued rising from the resting potential value. In the eggs displaying a short duration of membrane depolarization, the second period of depolarization was shortened (lasting only 3.5 +/- 0.5 min) since it lacked the second plateau. In addition it displayed a smaller number of oscillations (n = 4.7 +/- 0.6). As a consequence of this shortening, the membrane repolarized sooner. After repolarization, the membrane displayed several potential oscillations that started from the repolarization level. Regardless of the length of the depolarized plateau phases, the total number of membrane oscillations and the time period during which they occurred were constant. Eggs displaying a long depolarization phase had 15.9 +/- 0.6 oscillations in a 19.5 +/- 0.6 min interval, while eggs having a short depolarization phase had 16.0 +/- 0.8 oscillations in a 18.1 +/- 0.3 min interval. The time period during which the potential oscillations occurred corresponded remarkably well with the time of the meiotic divisions: the formation of the first polar body was detected about 80 sec after the end of the first series of oscillations; the second polar body was extruded about 85 sec after the last membrane oscillation occurred.
海鞘的受精电位由最初的快速去极化组成。这种最初由精子触发的去极化之后是一个膜去极化阶段，其持续时间有长有短，这取决于卵。当持续时间长时，膜去极化阶段分为两个时期：第一个时期开始于一个平台期（膜电位Em = +20.2 ± 1.1 mV；持续时间 = 1.7 ± 0.14分钟），随后是一系列持续2.4 ± 0.2分钟的膜电位振荡（振荡次数n = 3.1 ± 0.25）。第二个时期同样开始于一个平台期（膜电位Em约为0 mV；持续时间 = 3.40 ± 0.20分钟），随后是一系列持续11.8 ± 0.6分钟的振荡（振荡次数n = 11.5 ± 0.5），接着是膜复极化。第二系列振荡常常从静息电位值开始持续上升。在显示膜去极化持续时间短的卵中，第二个去极化时期被缩短（仅持续3.5 ± 0.5分钟），因为它没有第二个平台期。此外，它显示的振荡次数较少（振荡次数n = 4.7 ± 0.6）。由于这种缩短，膜更快地复极化。复极化后，膜显示出几次从复极化水平开始的电位振荡。无论去极化平台期的长度如何，膜振荡的总数及其发生的时间段是恒定的。显示长去极化期的卵在19.5 ± 0.6分钟的间隔内有15.9 ± 0.6次振荡，而具有短去极化期的卵在18.1 ± 0.3分钟的间隔内有16.0 ± 0.8次振荡。电位振荡发生的时间段与减数分裂的时间非常吻合：在第一系列振荡结束后约80秒检测到第一极体的形成；在最后一次膜振荡发生后约85秒挤出第二极体。
