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The role of voltage-gated Ca2+ channels in anoxic injury of spinal cord white matter.
- Source :
-
Brain research [Brain Res] 1999 Jan 30; Vol. 817 (1-2), pp. 84-92. - Publication Year :
- 1999
-
Abstract
- Dorsal column axons of the rat spinal cord are partially protected from anoxic injury following blockade of voltage-sensitive Na+ channels and the Na+/--Ca2+ exchanger. To examine the potential contribution of voltage-gated Ca2+ channels to anoxic injury of spinal cord axons, we studied axonal conduction in rat dorsal columns in vitro following a 60-min period of anoxia. Glass microelectrodes were used to record field potentials from the dorsal columns following distal local surface stimulation. Perfusion solutions containing blockers of voltage-gated Ca2+ channels were introduced 60 min prior to onset of anoxia and continued until 10 min after reoxygenation. Pharmacological blocking agents which are relatively selective for L- (verapamil, diltiazem, nifedipine) and N- (omega-conotoxin GVIA) type calcium channels were significantly protective against anoxia-induced loss of conduction, as was non-specific block using divalent cations. Other Ca2+ channel blockers (neomycin and omega-conotoxin MVIIC) that affect multiple Ca2+ channel types were also neuroprotective. Ni2+, which preferentially blocks R-type Ca2+ channels more than T-type channels, was also protective in a dose-dependent manner. These data suggest that the influx of Ca2+, through L-, N- and possibly R-type voltage-gated Ca2+ channels, participates in the pathophysiology of the Ca2+-mediated injury of spinal cord axons that is triggered by anoxia.<br /> (Copyright 1999 Elsevier Science B.V.)
- Subjects :
- Animals
Calcium Channel Blockers pharmacology
Calcium Channels drug effects
Cations, Divalent pharmacology
Electric Stimulation
Female
Hypoxia pathology
Membrane Potentials drug effects
Membrane Potentials physiology
Peptides pharmacology
Rats
Rats, Wistar
Sodium-Calcium Exchanger physiology
Sodium-Potassium-Exchanging ATPase metabolism
Spinal Cord drug effects
omega-Conotoxin GVIA
Axons pathology
Calcium Channels physiology
Hypoxia physiopathology
Ion Channel Gating
Spinal Cord pathology
omega-Conotoxins
Subjects
Details
- Language :
- English
- ISSN :
- 0006-8993
- Volume :
- 817
- Issue :
- 1-2
- Database :
- MEDLINE
- Journal :
- Brain research
- Publication Type :
- Academic Journal
- Accession number :
- 9889329
- Full Text :
- https://doi.org/10.1016/s0006-8993(98)01214-1