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L-type calcium channels and NMDA receptors: a determinant duo for short-term nociceptive plasticity.
- Source :
-
The European journal of neuroscience [Eur J Neurosci] 2007 Jan; Vol. 25 (1), pp. 127-35. - Publication Year :
- 2007
-
Abstract
- In the dorsal horn of the spinal cord, pain-transmitting neurons exhibit action potential windup, a form of short-term plasticity, which consists of a progressive increase in neuronal response during repetitive stimulation of nociceptive input fibers. Windup depends on N-methyl-D-aspartate (NMDA) receptor activation, but previous in vitro studies indicated that windup also relies on intrinsic plateau properties of spinal neurons. In the present study, we considered the possible involvement of these properties in windup in vivo. For this purpose, we first studied a nociceptive flexion reflex in the rat. We showed that windup of the reflex is actually suppressed by blockers of L-type calcium current and Ca(2+)-activated non-specific cationic current (Ican), the two main depolarizing conductances of plateau potentials. We further showed that, during windup, NMDA receptors provide a critical excitatory component in a dynamic balance of excitatory and inhibitory inputs which ultimately activates L-type calcium channels. The nociceptive reflex involves at least two neuronal groups, which may express intrinsic amplification properties, motor neurons and dorsal horn neurons. By means of extracellular recordings in the dorsal horn, we showed that windup of dorsal horn neuron discharge was sensitive to the modulators of L-type calcium current. Altogether, our results suggest that, in vivo, windup also depends on the amplification properties of spinal neurons, the triggering of which requires previous activation of NMDA receptors.
- Subjects :
- 2-Amino-5-phosphonovalerate pharmacology
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester pharmacology
Action Potentials drug effects
Action Potentials physiology
Action Potentials radiation effects
Animals
Animals, Newborn
Calcium Channel Agonists pharmacology
Calcium Channel Blockers pharmacology
Dizocilpine Maleate pharmacology
Dose-Response Relationship, Radiation
Drug Interactions
Electric Stimulation adverse effects
Excitatory Amino Acid Antagonists pharmacology
Glycine Agents pharmacology
In Vitro Techniques
Models, Biological
Neuronal Plasticity drug effects
Neurons drug effects
Neurons physiology
Nociceptors drug effects
Physical Stimulation adverse effects
Rats
Rats, Wistar
Reflex drug effects
Reflex radiation effects
Spinal Cord cytology
Strychnine pharmacology
Calcium Channels, L-Type physiology
Neuronal Plasticity physiology
Nociceptors physiopathology
Receptors, N-Methyl-D-Aspartate physiology
Subjects
Details
- Language :
- English
- ISSN :
- 0953-816X
- Volume :
- 25
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The European journal of neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 17241274
- Full Text :
- https://doi.org/10.1111/j.1460-9568.2006.05256.x