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Fast Inactivation of Delayed Rectifier K Conductance in Squid Giant Axon and Its Cell Bodies
| Content Provider | Scilit |
|---|---|
| Author | Mathes, Chris Rosenthal, Joshua J. C. Armstrong, Clay M. Gilly, William F. |
| Copyright Year | 1997 |
| Description | Journal: The Journal of general physiology Inactivation of delayed rectifier K conductance $(g_{K}$) was studied in squid giant axons and in the somata of giant fiber lobe (GFL) neurons. Axon measurements were made with an axial wire voltage clamp by pulsing to $V_{K}$ (∼−10 mV in 50–70 mM external K) for a variable time and then assaying available $g_{K}$ with a strong, brief test pulse. GFL cells were studied with whole-cell patch clamp using the same prepulse procedure as well as with long depolarizations. Under our experimental conditions (12–18°C, 4 mM internal MgATP) a large fraction of $g_{K}$ inactivates within 250 ms at −10 mV in both cell bodies and axons, although inactivation tends to be more complete in cell bodies. Inactivation in both preparations shows two kinetic components. The faster component is more temperature-sensitive and becomes very prominent above 12°C. Contribution of the fast component to inactivation shows a similar voltage dependence to that of $g_{K}$, suggesting a strong coupling of this inactivation path to the open state. Omission of internal MgATP or application of internal protease reduces the amount of fast inactivation. High external K decreases the amount of rapidly inactivating $I_{K}$ but does not greatly alter inactivation kinetics. Neither external nor internal tetraethylammonium has a marked effect on inactivation kinetics. Squid delayed rectifier K channels in GFL cell bodies and giant axons thus share complex fast inactivation properties that do not closely resemble those associated with either C-type or N-type inactivation of cloned Kv1 channels studied in heterologous expression systems. |
| Related Links | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2219430/pdf http://jgp.rupress.org/content/jgp/109/4/435.full.pdf |
| ISSN | 00221295 |
| DOI | 10.1085/jgp.109.4.435 |
| Journal | The Journal of general physiology |
| Issue Number | 4 |
| Volume Number | 109 |
| Language | English |
| Publisher | Rockefeller University Press |
| Publisher Date | 1997-04-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Journal of general physiology Neurosciences Voltage Clamp Phosphorylation |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology |
