Membrane potential of the unfertilized sea urchin egg |
| |
| Authors: | L A Jaffe K R Robinson |
| |
| Institution: | 1. Department of Physiology, University of California, Los Angeles, California 90024 USA;2. Department of Biology, Purdue University, West Lafayette, Indiana 47907 USA |
| |
| Abstract: | The membrane potential, specific resistance, and potassium selectivity of the unfertilized Strongylocentrotus purpuratus egg were determined by two independent methods: tracer flux and microelectrode. The potassium influx was 0.50 ± 0.2 pmole/cm2· sec, which was greater than the sodium, chloride, and calcium influxes by factors of 4, 7, and 75, respectively. By means of the constant-field equations, the flux data were used to calculate membrane potential (?70 mV) and specific resistance (420 kΩ · cm2). The effect of the external potassium concentration on the sodium influx was determined and the results closely fit the result expected if the membrane behaved as a potassium electrode. Microelectrode measurements of the potential and resistance were ?75 ± 3 mV and 380 ± kΩ · cm2. |
| |
| Keywords: | To whom reprint requests should be sent Present address: Division of Molecular and Cellular Biology National Jewish Hospital 3800 E Colfax Avenue Denver Colorado 80206 |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
