| Title | Kv7/KCNQ channels control action potential phasing of pyramidal neurons during hippocampal gamma oscillations in vitro. | | Author(s) | Leão RN, Tan HM, Fisahn A | | Institution | Department of Neuroscience, Neuronal Oscillations Laboratory, Karolinska Institute, 17177 Stockholm, Sweden. | | Source | J Neurosci 2009 Oct 21; 29(42):13353-64. | | MeSH | Action Potentials
Animals
Animals, Newborn
Anthracenes
Barium Compounds
Biological Clocks
Biophysics
Chlorides
Dose-Response Relationship, Drug
Electric Stimulation
Electroencephalography
Excitatory Amino Acid Agonists
Fourier Analysis
Hippocampus
Indoles
KCNQ Potassium Channels
Kainic Acid
Models, Neurological
Patch-Clamp Techniques
Potassium Channel Blockers
Pyramidal Cells
Pyridines
Rats
Rats, Sprague-Dawley
| | Abstract | While the synaptic mechanisms involved in the generation of in vitro network oscillations have been widely studied, little is known about the importance of voltage-gated currents during such activity. Here we study the role of the M-current (I(M)) in the modulation of network oscillations in the gamma-frequency range (20-80 Hz). Kv7/KCNQ subunits, the molecular correlates of I(M), are abundantly expressed in CA1 and CA3 pyramidal neurons, and I(M) is an important modulator of pyramidal neuron firing. Using hippocampal slices, we recorded field activity and pyramidal neuron action potential timing during kainate-induced gamma oscillations. Application of the specific I(M) blocker XE991 causes a significant reduction of gamma oscillation amplitude with no significant change in oscillation frequency. Concomitant CA3 pyramidal neuron recordings show a significant increase in action potential frequency during ongoing gamma oscillations after the application of XE991. This increase is associated with a significant loss of periodicity of pyramidal neuron action potentials relative to the phase of the gamma oscillations. Using dynamic clamp, we show that I(M) acts to improve the periodicity of action potential timing and to decrease action potential frequency. We further validate these results in a compartmental model of a pyramidal neuron. Our work suggests that I(M) modulates gamma oscillations by regulating the phasing of action potential firing in pyramidal neurons. | | Language | eng | | Pub Type(s) | In Vitro
Journal Article
Research Support, Non-U.S. Gov't
| | PubMed ID | 19846723 |
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