Cl - channels in Chara
| Autor: | M. J. Beilby |
|---|---|
| Rok vydání: | 1982 |
| Předmět: | |
| Zdroj: | Philosophical Transactions of the Royal Society of London. B, Biological Sciences. 299:435-445 |
| ISSN: | 2054-0280 0080-4622 |
| DOI: | 10.1098/rstb.1982.0142 |
| Popis: | The action potential in the cells of the freshwater alga Chara corallina is slower than that in the nerve by about 1000-fold. The depolarization phase is brought on by the outflow of the Cl - ions. Voltage-clamp studies show that this Cl - current can be described by the Hodgkin-Huxley equations for the Na+ transient in the squid axon. The only change necessary to the form of the Hodgkin-Huxley equations is an introduction of a time delay between the stimulus and the onset of excitation. This mathematical model of the Chara action potential facilitates a quantitative description of the effects of pH and temperature. While a pH shift alters various Hodgkin-Huxley parameters, temperature change influences mainly the activation and inactivation time constants but leaves the voltage-dependence of these parameters unaffected. The delays in excitation are both temperature and potential dependent. In future some corrections to the Hodgkin-Huxley picture of the Chara action potential may be necessary, as recent impedance measurements suggest a change in the membrane capacitance at the time of excitation. |
| Databáze: | OpenAIRE |
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