Sodium-dependent plateau potentials in electrocytes of the electric fish Gymnotus carapo
| Autor: | Virginia Comas, Washington Buño, Felipe Sierra, Omar Macadar |
|---|---|
| Rok vydání: | 2004 |
| Předmět: |
Patch-Clamp Techniques
Potassium Channels Physiology Action Potentials Tetrodotoxin In Vitro Techniques Sodium Channels Behavioral Neuroscience Plateau potentials Current clamp Animals Gymnotus Electric fish Ecology Evolution Behavior and Systematics Two electrode voltage clamp Electric Organ Muscle Cells Ion Transport biology Chemistry Sodium Electric Conductivity Gymnotiformes Depolarization Anatomy biology.organism_classification Electrophysiology Biophysics Animal Science and Zoology Sodium dependent Sodium Channel Blockers |
| Zdroj: | Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology. 191(1) |
| ISSN: | 0340-7594 |
| Popis: | The weakly electric fish Gymnotus carapo emits a triphasic electric organ discharge generated by muscle-derived electrocytes, which is modified by environmental and physiological factors. Two electrode current clamp recordings in an in vitro preparation showed that Gymnotus electrocytes fired repetitively and responded with plateau potentials when depolarized. This electrophysiological behavior has never been observed in electrocytes from related species. Two types of plateaus with different thresholds and amplitudes were evoked by depolarization when Na(+)-dependent currents were isolated in a K(+)- and Ca(2+)-free solution containing TEA and 4-AP. Two electrode voltage clamp recordings revealed a classical fast activating-inactivating Na+ current and two persistent Na(+)-dependent currents with voltage-dependencies consistent with the action potential (AP) and the two plateaus observed under current clamp, respectively. The three currents, the APs and the plateaus were reduced by TTX, and were absent in Na(+)-free solution. The different Na(+)-dependent currents in Gymnotus electrocytes may be targets for the modifications of the electric organ discharge mediated by environmental and physiological factors. |
| Databáze: | OpenAIRE |
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