Bioelectric Responses of the Echinoderm Egg to Fertilization
| Autor: | L. Lundin, R. A. Steinhardt, D. Mazia |
|---|---|
| Rok vydání: | 1971 |
| Předmět: |
animal structures
Cell Membrane Permeability Biological Sciences: Zoology Action Potentials Biological Transport Active Biology Membrane Potentials Human fertilization Dendraster excentricus Botany Animals Repolarization health care economics and organizations Ovum Ions Membrane potential Multidisciplinary urogenital system Sodium Depolarization Lytechinus Hyperpolarization (biology) biology.organism_classification Resting potential Electrodes Implanted Fertilization Pronase Sea Urchins embryonic structures Potassium Biophysics Female Echinodermata |
| Zdroj: | Proceedings of the National Academy of Sciences. 68:2426-2430 |
| ISSN: | 1091-6490 0027-8424 |
| DOI: | 10.1073/pnas.68.10.2426 |
| Popis: | The fertilization reaction of echinoderm eggs ( Lytechinus pictus , a sea urchin, and Dendraster excentricus , a sand dollar) was followed with intracellular electrodes. Membrane potential and K + activity were recorded. The unfertilized egg of Lytechinus has a membrane potential of -8 mV, inside negative. Within 5 sec after the addition of sperm, a fertilization action potential develops, going to +10 mV, inside positive. The time from the initial depolarization to a return to the original -8 mV is 120-150 sec. The repolarization continues until a potential of -10 to -14 mV is reached, at which point it pauses for 3-4 min. At 6-8 min after fertilization, a further and relatively rapid hyperpolarization begins, going to -60 to -65 mV by 15-25 min after fertilization and remaining constant at these values. The membrane potential of the unfertilized egg appears to depend on a general permeability to anions. The fertilization action potential seems to reflect a prolonged influx of sodium. The final depolarization to -60 mV is attributable to the development of potassium conductance. Simultaneous measurements with a K + ion-selective electrode gives constant readings of about 240 mM K + in the unfertilized eggs throughout the fertilization process. Similar results were obtained with Dendraster eggs. The resting potential of the unfertilized eggs was -7 mV; the action potential on activation attained +18 mV; the repolarization paused at -16 to -24 mV and the final potential attained was -70 mV. The electrical changes after fertilization with spermatozoa or activation with Pronase were identical. |
| Databáze: | OpenAIRE |
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