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An N-methyl-D-aspartate receptor mediated large, low-frequency, spontaneous excitatory postsynaptic current in neonatal rat spinal dorsal horn neurons.
- Source :
-
Neuroscience [Neuroscience] 2006 Sep 01; Vol. 141 (3), pp. 1489-501. Date of Electronic Publication: 2006 Jun 05. - Publication Year :
- 2006
-
Abstract
- Examples of spontaneous oscillating neural activity contributing to both pathological and physiological states are abundant throughout the CNS. Here we report a spontaneous oscillating intermittent synaptic current located in lamina I of the neonatal rat spinal cord dorsal horn. The spontaneous oscillating intermittent synaptic current is characterized by its large amplitude, slow decay time, and low-frequency. We demonstrate that post-synaptic N-methyl-D-aspartate receptors (NMDARs) mediate the spontaneous oscillating intermittent synaptic current, as it is inhibited by magnesium, bath-applied d-2-amino-5-phosphonovalerate (APV), or intracellular MK-801. The NR2B subunit of the NMDAR appears important to this phenomenon, as the NR2B subunit selective NMDAR antagonist, alpha-(4-hydroxphenyl)-beta-methyl-4-benzyl-1-piperidineethanol tartrate (ifenprodil), also partially inhibited the spontaneous oscillating intermittent synaptic current. Inhibition of spontaneous glutamate release by the AMPA/kainate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or the mu-opioid receptor agonist [D-Ala2, N-Me-Phe4, Gly5] enkephalin-ol (DAMGO) inhibited the spontaneous oscillating intermittent synaptic current frequency. Marked inhibition of spontaneous oscillating intermittent synaptic current frequency by tetrodotoxin (TTX), but not post-synaptic N-(2,6-dimethylphenylcarbamoylmethyl)triethylammonium bromide (QX-314), suggests that the glutamate release important to the spontaneous oscillating intermittent synaptic current is dependent on active neural processes. Conversely, increasing dorsal horn synaptic glutamate release by GABAA or glycine inhibition increased spontaneous oscillating intermittent synaptic current frequency. Moreover, inhibiting glutamate transporters with threo-beta-benzyloxyaspartic acid (DL-TBOA) increased spontaneous oscillating intermittent synaptic current frequency and decay time. A possible functional role of this spontaneous NMDAR-mediated excitatory postsynaptic current in modulating nociceptive transmission within the spinal cord is discussed.
- Subjects :
- Adrenergic alpha-Antagonists pharmacology
Analgesics, Opioid pharmacology
Animals
Animals, Newborn
Aspartic Acid pharmacology
Dose-Response Relationship, Drug
Electric Stimulation methods
Enkephalin, Ala(2)-MePhe(4)-Gly(5)- pharmacology
Excitatory Amino Acid Antagonists pharmacology
Excitatory Postsynaptic Potentials drug effects
Excitatory Postsynaptic Potentials radiation effects
In Vitro Techniques
Lidocaine analogs & derivatives
Lidocaine pharmacology
Magnesium pharmacology
Neural Inhibition drug effects
Neural Inhibition physiology
Neural Inhibition radiation effects
Patch-Clamp Techniques methods
Piperidines pharmacology
Posterior Horn Cells drug effects
Posterior Horn Cells radiation effects
Rats
Rats, Sprague-Dawley
Tetrodotoxin pharmacology
Excitatory Postsynaptic Potentials physiology
Posterior Horn Cells physiology
Receptors, N-Methyl-D-Aspartate physiology
Spinal Cord cytology
Subjects
Details
- Language :
- English
- ISSN :
- 0306-4522
- Volume :
- 141
- Issue :
- 3
- Database :
- MEDLINE
- Journal :
- Neuroscience
- Publication Type :
- Academic Journal
- Accession number :
- 16750886
- Full Text :
- https://doi.org/10.1016/j.neuroscience.2006.04.049