The Journal of Neuroscience, October 1, 1999, 19(19):8271-8280
NMDA-Induced Dendritic Oscillations during a Soma Voltage Clamp
of Chick Spinal Neurons
L. E.
Moore1,
N.
Chub2,
J.
Tabak2, and
M.
O'Donovan2
1 Laboratoire de Neurobiologie des Reseaux
Sensorimoteurs, UPRESA-7060, Paris, France, and
2 Laboratory of Neural Control, National Institutes of
Health, Bethesda, Maryland 20892
An investigation of dendritic membrane properties was performed by
whole-cell patch measurements of the biophysical properties of intact
chick spinal neurons that are involved in rhythmogenesis. A whole-cell
voltage clamp of the somatic membrane was used to block NMDA-induced
voltage oscillations from the cell body, thus partially isolating the
intrinsic oscillatory properties of dendritic membranes from those of
the soma. An experimental approach was developed that takes into
account the complexity of the dendritic tree in an environment as
normal as possible, without the need for cell isolation or slice
preparations. A computational study of the experimentally determined
model showed that excitatory amino acid receptors on dendrites can
dynamically control the electrotonic length of the dendrites through
the activation of negative slope conductances. These experiments
demonstrate the presence of NMDA receptors on the dendrites and that
they induce intrinsic oscillations when the synaptic input from other
cells is significantly reduced.
Key words:
dendritic oscillations; chick spinal neurons; NMDA; electrotonic structure; frequency domain; impedance
Copyright © 1999 Society for Neuroscience 0270-6474/99/19198271-10$05.00/0
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