Sperm Initiate a Ca2+ Wave in Frog Eggs that is More Similar to Ca2+ Waves Initiated by IP3 than by Ca2+
| Autor: | Richard Nuccitelli, Bridget B. Eutenier, Andrej Bugrim, Joel Keizer, Ray A Fontanilla |
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| Rok vydání: | 2003 |
| Předmět: |
Male
Xenopus Biophysics Receptors Cytoplasmic and Nuclear Biophysical Theory and Modeling Biology Endoplasmic Reticulum Models Biological Membrane Potentials Diffusion Xenopus laevis Human fertilization Botany Animals Inositol 1 4 5-Trisphosphate Receptors Computer Simulation Calcium Signaling Diffusion (business) Calcium signaling Ovum Membrane potential Voltage-dependent calcium channel Endoplasmic reticulum biology.organism_classification Sperm Spermatozoa Fertilization Calcium Calcium Channels Ion Channel Gating |
| Zdroj: | Biophysical Journal. 84(3):1580-1590 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/s0006-3495(03)74968-6 |
| Popis: | We have measured the initial propagation velocity of the sperm-induced Ca(2+) wave in the egg of Xenopus laevis and have compared it with the initial propagation velocities of the inositol triphosphate (IP(3))-induced and Ca(2+)-induced Ca(2+) waves. The initial mean propagation velocity of the sperm-induced wave (13 microm/s) is very similar to that of the IP(3)-induced waves (12.3 microm/s) and two times faster than the mean Ca(2+)-induced wave velocity (6.6 microm/s). We have generated realistic simulations of the fertilization wave in the frog egg using a computational technique based on the finite difference method. Modeling refinements presented here include equations for the production, degradation, and diffusion of IP(3), a description for Ca(2+) dynamics in the endoplasmic reticulum, and a highly concentrated endoplasmic reticulum in the egg cortex. We conclude that models incorporating sperm-induced IP(3) generation fit the data best and those involving the influx of either Ca(2+) or a diffusible sperm factor fit the data poorly. This independence from Ca(2+) influx is also supported by electrophysiological data indicating that Ca(2+) influx is not needed to maintain open Cl(-) channels that generate the fertilization potential. |
| Databáze: | OpenAIRE |
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