Activation of NMDA receptors drives action potentials in superficial dorsal horn from neonatal rats.
We have investigated the role of NMDA receptors in mediating synaptic transmission in spinal cord lamina II over the first 2 weeks of postnatal development. High intensity root stimulation evoked D-APV-sensitive slow synaptic activity in lamina II neurons that drove action potential firing. This NMDA receptor-mediated activity was enhanced when bicuculline and strychnine were used to block synaptic inhibition. When activated by repetitive focal stimulation, synaptic activity mediated by NMDA receptors alone drove action potential firing. NMDA receptors were also able to drive action potential firing at synapses where AMPA receptors were present but blocked. Our data show that in lamina II of the dorsal horn, NMDA receptors significantly affect neuronal excitability even in the absence of co-activation of AMPA receptors.
Bardoni
R
R
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Italy.
Magherini
P C
PC
MacDermott
A B
AB
D000200:Action Potentials / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001640:Bicuculline / Q000494:pharmacology; D004558:Electric Stimulation / Q000379:methods; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D018756:GABA Antagonists / Q000494:pharmacology; D018684:Glycine Agents / Q000494:pharmacology; D066298:In Vitro Techniques; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D013126:Spinal Nerve Roots / Q000502:physiology; D013331:Strychnine / Q000494:pharmacology; D013569:Synapses / Q000187:drug effects / Q000502:physiology
D018756:GABA Antagonists; D018684:Glycine Agents; D016194:Receptors, N-Methyl-D-Aspartate; D013331:Strychnine; D001640:Bicuculline