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Properties of transient K+ currents and underlying single K+ channels in rat olfactory receptor neurons.
| Content Provider | Scilit |
|---|---|
| Author | Lynch, J. W. Barry, P. H. |
| Copyright Year | 1991 |
| Description | Journal: The Journal of general physiology The transient potassium current, IK(t), of enzymatically dissociated rat olfactory receptor neurons was studied using patch-clamp techniques. Upon depolarization from negative holding potentials, IK(t) activated rapidly and then inactivated with a time course described by the sum of two exponential components with time constants of 22.4 and 143 ms. Single-channel analysis revealed a further small component with a time constant of several seconds. Steady-state inactivation was complete at -20 mV and completely removed at -80 mV (midpoint -45 mV). Activation was significant at -40 mV and appeared to reach a maximum conductance at +40 mV (midpoint -13 mV). Deactivation was described by the sum of two voltage-dependent exponential components. Recovery from inactivation was extraordinarily slow (50 s at -100 mV) and the underlying processes appeared complex. IK(t) was reduced by 4-aminopyridine and tetraethylammonium applied externally. Increasing the external K+ concentration ([K+]o) from 5 to 25 mM partially removed IK(t) inactivation, usually without affecting activation kinetics. The elevated [K+]o also hyperpolarized the steady-state inactivation curve by 9 mV and significantly depolarized the voltage dependence of activation. Single transient K+ channels, with conductances of 17 and 26 pS, were observed in excised patches and often appeared to be localized into large clusters. These channels were similar to IK(t) in their kinetic, pharmacological, and voltage-dependent properties and their inactivation was also subject to modulation by [K+]o. The properties of IK(t) imply a role in action potential repolarization and suggest it may also be important in modulating spike parameters during neuronal burst firing. A simple method is also presented to correct for errors in the measurement of whole-cell resistance (Ro) that can result when patch-clamping very small cells. The analysis revealed a mean corrected Ro of 26 G omega for these cells. |
| Related Links | http://jgp.rupress.org/content/97/5/1043.full.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2216501/pdf https://rupress.org/jgp/article-pdf/97/5/1043/600033/1043.pdf |
| ISSN | 00221295 |
| DOI | 10.1085/jgp.97.5.1043 |
| Journal | The Journal of general physiology |
| Issue Number | 5 |
| Volume Number | 97 |
| Language | English |
| Publisher | Rockefeller University Press |
| Publisher Date | 1991-05-01 |
| Access Restriction | Open |
| Subject Keyword | Journal: The Journal of general physiology Action Potential Time Constant Burst Firing Patch Clamp Steady State Membrane Potentials Patch Clamp Technique Potassium Channels Electrophysiology |
| Content Type | Text |
| Resource Type | Article |
| Subject | Physiology |
