Spinal seizures and excitatory amino acid-mediated synaptic transmission.
In the isolated frog spinal cord penicillin or strychnine produced spinal seizures with spontaneous slow paroxysmal ventral root depolarizations (pVRDs) and superimposed motoneuron spikes. Mn2+, tetrodotoxin, mephenesin and low [Na+]o suppressed pVRDs, an indication that paroxysmal activity requires intact excitatory synaptic transmission involving interneurons. Compounds reducing the release of amino acids [-)baclofen) or interfering with the activation of N-methyl-D-aspartic acid (NMDA) receptors (D,L-alpha-aminoadipate, D-2-amino-5-phosphonovalerate, gamma-D-glutamylglycine) eliminated pVRDs. The results suggest that synaptic release of excitatory amino acids (e.g. L-glutamate, L-aspartate) and subsequent activation of specific receptors sensitive to the action of NMDA underlie spinal convulsions.
D000344:Afferent Pathways / Q000187:drug effects; D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials / Q000187:drug effects; D005727:Ganglia, Spinal / Q000187:drug effects; D010406:Penicillins; D011898:Ranidae; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface / Q000187:drug effects; D012640:Seizures / Q000139:chemically induced*; D013116:Spinal Cord / Q000187:drug effects*; D013331:Strychnine; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
D000596:Amino Acids; D010406:Penicillins; D017459:Receptors, Amino Acid; D011956:Receptors, Cell Surface; D013331:Strychnine