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Three types of sodium channels in adult rat dorsal root ganglion neurons.
- Source :
-
Brain research [Brain Res] 1992 Oct 02; Vol. 592 (1-2), pp. 283-97. - Publication Year :
- 1992
-
Abstract
- Several types of Na+ currents have previously been demonstrated in dorsal root ganglion (DRG) neurons isolated from neonatal rats, but their expression in adult neurons has not been studied. Na+ current properties in adult dorsal root ganglion (DRG) neurons of defined size class were investigated in isolated neurons maintained in primary culture using a combination of microelectrode current clamp, patch voltage clamp and immunocytochemical techniques. Intracellular current clamp recordings identified differing relative contributions of TTX-sensitive and -resistant inward currents to action potential waveforms in DRG neuronal populations of defined size. Patch voltage clamp recordings identified three distinct kinetic types of Na+ current differentially distributed among these size classes of DRG neurons. 'Small' DRG neurons co-express two types of Na+ current: (i) a rapidly-inactivating, TTX-sensitive 'fast' current and (ii) a slowly-activating and -inactivating, TTX-resistant 'slow' current. The TTX-sensitive Na+ current in these cells was almost completely inactivated at typical resting potentials. 'Large' cells expressed a single TTX-sensitive Na+ current identified as 'intermediate' by its inactivation rate constants. 'Medium'-sized neurons either co-expressed 'fast' and 'slow' current or expressed only 'intermediate' current. Na+ channel expression in these size classes was also measured by immunocytochemical techniques. An antibody against brain-type Na+ channels (Ab7493)10 labeled small and large neurons with similar intensity. These results demonstrate that three types of Na+ currents can be detected which correlate with electrogenic properties of physiologically and anatomically distinct populations of adult rat DRG neurons.
- Subjects :
- Action Potentials drug effects
Animals
Calcium physiology
Electrophysiology
Ganglia, Spinal cytology
Immunohistochemistry methods
Neurons cytology
Rats
Rats, Wistar
Sodium physiology
Sodium Channels physiology
Staining and Labeling
Tetrodotoxin pharmacology
Ganglia, Spinal metabolism
Neurons metabolism
Sodium Channels metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 0006-8993
- Volume :
- 592
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 1280518
- Full Text :
- https://doi.org/10.1016/0006-8993(92)91687-a