Bischofberger, Joseph; Jonas, Peter MISTA
1. Dendritic patch-clamp recordings were obtained from mitral cells in rat olfactory bulb slices, up to 350 μm from the soma. Simultaneous dendritic and somatic whole-cell recordings indicated that action potentials (APs) evoked by somatic or dendritic current injection were initiated near the soma. Both the large amplitude (100.7 ± 1.1 mV) and the short duration (1.38 ± 0.07 ms) of the AP were maintained as the AP propagated back into the primary mitral cell dendrites. 2. Outside-out patches isolated from mitral cell dendrites contained voltage-gated Na+ channels (peak conductance density, 90 pS μm-2 at -10 mV). When an AP was used as a somatic voltage-clamp command in the presence of 1 μM tetrodotoxin (TTX), the amplitude of the dendritic potential was attenuated to 48 ± 14 mV. This shows that dendritic Na+ channels support the active back-propagation of APs. 3. Dendritic patches contained voltage-gated K+ channels with high density (conductance density, 513 pS μm-2 at 30 mV. Dendritic K+ currents were reduced to 35% by 1 mM external tetraethylammonium chloride (TEACl). When an AP was used as a somatic voltage clamp command in the presence of TEACl, the dendritic potential was markedly prolonged. This indicates that dendritic K+ channels mediate the fast repolarization of dendritic APs. 4. We conclude that voltage gated Na+ and K+ channels support dendritic APs with large amplitudes and short durations that may trigger fast transmitter release at dendrodendritic synapses in the olfactory bulb.
Journal of Physiology
We thank Drs J. R. P. Geiger, M. Martina, and D. Schild for critically reading the manuscript, and Mrs B. Plessow-Freudenberg for technical assistance. This work was supported by DFG grant BI 642/1-1 and German Israeli Foundation grant I 0352-073.01/94.
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Bischofberger J, Jonas PM. Action potential propagation into the presynaptic dendrites of rat mitral cells. Journal of Physiology. 1997;504(Pt 2):359-365. doi:10.1111/j.1469-7793.1997.359be.x
Bischofberger, J., & Jonas, P. M. (1997). Action potential propagation into the presynaptic dendrites of rat mitral cells. Journal of Physiology. Wiley-Blackwell. https://doi.org/10.1111/j.1469-7793.1997.359be.x
Bischofberger, Joseph, and Peter M Jonas. “Action Potential Propagation into the Presynaptic Dendrites of Rat Mitral Cells.” Journal of Physiology. Wiley-Blackwell, 1997. https://doi.org/10.1111/j.1469-7793.1997.359be.x.
J. Bischofberger and P. M. Jonas, “Action potential propagation into the presynaptic dendrites of rat mitral cells,” Journal of Physiology, vol. 504, no. Pt 2. Wiley-Blackwell, pp. 359–365, 1997.
Bischofberger J, Jonas PM. 1997. Action potential propagation into the presynaptic dendrites of rat mitral cells. Journal of Physiology. 504(Pt 2), 359–365.
Bischofberger, Joseph, and Peter M. Jonas. “Action Potential Propagation into the Presynaptic Dendrites of Rat Mitral Cells.” Journal of Physiology, vol. 504, no. Pt 2, Wiley-Blackwell, 1997, pp. 359–65, doi:10.1111/j.1469-7793.1997.359be.x.
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