Abstract
We report here that in cerebellar Purkinje cells from which the axon has been removed, positive voltage steps applied to the voltage-clamped soma produce spikes of active current. The spikes are inward, are all-or-none, have a duration of approximately 1 ms, and are reversibly eliminated by tetrodotoxin, a Na channel poison. From cell to cell, the amplitude of the spikes ranges from 4 to 20 nA. Spike latency decreases as the depolarizing step is made larger. These spikes clearly arise at a site where the voltage is not controlled, remote from the soma. From these facts we conclude that Purkinje cell dendrites contain a sufficient density of Na channels to generate action potentials. Activation by either parallel fiber or climbing fiber synapses produces similar spikes, suggesting that normal input elicits Na action potentials in the dendrites. These findings greatly alter current views of how dendrites in these cells respond to synaptic input.
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- Benardo L. S., Masukawa L. M., Prince D. A. Electrophysiology of isolated hippocampal pyramidal dendrites. J Neurosci. 1982 Nov;2(11):1614–1622. doi: 10.1523/JNEUROSCI.02-11-01614.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Edwards F. A., Konnerth A., Sakmann B., Takahashi T. A thin slice preparation for patch clamp recordings from neurones of the mammalian central nervous system. Pflugers Arch. 1989 Sep;414(5):600–612. doi: 10.1007/BF00580998. [DOI] [PubMed] [Google Scholar]
- Huguenard J. R., Hamill O. P., Prince D. A. Sodium channels in dendrites of rat cortical pyramidal neurons. Proc Natl Acad Sci U S A. 1989 Apr;86(7):2473–2477. doi: 10.1073/pnas.86.7.2473. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Konnerth A., Llano I., Armstrong C. M. Synaptic currents in cerebellar Purkinje cells. Proc Natl Acad Sci U S A. 1990 Apr;87(7):2662–2665. doi: 10.1073/pnas.87.7.2662. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Llinás R., Sugimori M. Electrophysiological properties of in vitro Purkinje cell dendrites in mammalian cerebellar slices. J Physiol. 1980 Aug;305:197–213. doi: 10.1113/jphysiol.1980.sp013358. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Llinás R., Sugimori M. Electrophysiological properties of in vitro Purkinje cell somata in mammalian cerebellar slices. J Physiol. 1980 Aug;305:171–195. doi: 10.1113/jphysiol.1980.sp013357. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Regehr W. G., Connor J. A., Tank D. W. Optical imaging of calcium accumulation in hippocampal pyramidal cells during synaptic activation. Nature. 1989 Oct 12;341(6242):533–536. doi: 10.1038/341533a0. [DOI] [PubMed] [Google Scholar]
- Ross W. N., Werman R. Mapping calcium transients in the dendrites of Purkinje cells from the guinea-pig cerebellum in vitro. J Physiol. 1987 Aug;389:319–336. doi: 10.1113/jphysiol.1987.sp016659. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Tank D. W., Sugimori M., Connor J. A., Llinás R. R. Spatially resolved calcium dynamics of mammalian Purkinje cells in cerebellar slice. Science. 1988 Nov 4;242(4879):773–777. doi: 10.1126/science.2847315. [DOI] [PubMed] [Google Scholar]
- Wong R. K., Prince D. A., Basbaum A. I. Intradendritic recordings from hippocampal neurons. Proc Natl Acad Sci U S A. 1979 Feb;76(2):986–990. doi: 10.1073/pnas.76.2.986. [DOI] [PMC free article] [PubMed] [Google Scholar]