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Fast pre-potential generation in rat hippocampal CA1 pyramidal neurons
R W Turner1, D E Meyers, J L Barker
1Laboratory of Neurophysiology, National Institutes of Health, NINCDS, Bethesda, MD.
Neuroscience
|April 1, 1993
Summary
Small all-or-none pre-potentials precede sodium (Na+) spike discharge in hippocampal pyramidal neurons. This study reveals these potentials reflect distant spike activity and are crucial for neuronal communication.
Area of Science:
- Neuroscience
- Cellular Electrophysiology
Background:
- Small all-or-none pre-potentials are linked to spike discharge in hippocampal pyramidal neurons.
- These potentials may represent activity in distant axonal or dendritic regions or gap junction conduction.
Purpose of the Study:
- To compare somatic and dendritic pre-potentials.
- To investigate the relationship between pre-potentials and Na+ spike discharge using tetrodotoxin.
Main Methods:
- Intrasomatic and intradendritic recordings from CA1 pyramidal neurons in rat hippocampal slices.
- Evoked orthodromic and antidromic spike discharge via electrical stimulation.
- Focal application of tetrodotoxin to block Na+ spike discharge and uncover pre-potentials.
Main Results:
- Tetrodotoxin blockade of antidromic spikes uncovered pre-potentials, requiring remote diffusion for blockade.
- Orthodromic somatic pre-potentials were uncovered only at suprathreshold intensities, indicating dendritic initiation.
Conclusions:
- Na+ spike propagation along the pyramidal cell axis is preceded by a pre-potential.
- Dendritic spike discharge can generate fast pre-potentials in pyramidal cell somata.