title: An intracellular analysis of amino acid induced excitations of deep dorsal horn neurones in the rat spinal cord slice.
abstract: The rat spinal cord slice preparation has been used to investigate the sensitivity of deep dorsal horn neurones to the excitatory amino acids N-methyl-D-aspartate (NMDA), quisqualate and L-glutamate. Intracellular recordings were made from 44 neurones in laminae III-VI of 14- to 16-day rats. Superfusion of quisqualate (30 microM) excited all neurones, NMDA (50 microM) excited 72% and L-glutamate (0.5-1 mM) 63% of the neurones. Depolarizations were retained after tetrodotoxin but with a reduced amplitude. The NMDA antagonist D-aminophosphonovalerate (D-APV, 10 microM) reduced NMDA and L-glutamate depolarizations by 66% and by 40%, respectively, while the quisqualate responses were enhanced by 27%. Dorsal root stimulation elicited two main patterns of activity; short-latency single/double spikes followed by subthreshold excitatory postsynaptic potentials (EPSPs) or a burst of spikes rising from a long duration composite EPSP. D-APV reduced the long-latency components of the first type and reduced the amplitude and duration of the composite EPSP of the second. These results support a specialized role for NMDA receptors in synaptic transmission in the dorsal horn.
mesh_terms: D015763:2-Amino-5-phosphonovalerate; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000494:pharmacology; D004594:Electrophysiology; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates / Q000494:pharmacology*; D018698:Glutamic Acid; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000502:physiology; D016202:N-Methylaspartate; D010069:Oxadiazoles / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D016318:Quisqualic Acid; D051381:Rats; D013116:Spinal Cord / Q000187:drug effects* / Q000502:physiology; D013779:Tetrodotoxin / Q000494:pharmacology; D014633:Valine / Q000031:analogs & derivatives / Q000494:pharmacology
chemical_list: D000596:Amino Acids; D018691:Excitatory Amino Acid Antagonists; D005971:Glutamates; D010069:Oxadiazoles; D001224:Aspartic Acid; D018698:Glutamic Acid; D013779:Tetrodotoxin; D016202:N-Methylaspartate; D015763:2-Amino-5-phosphonovalerate; D016318:Quisqualic Acid; D014633:Valine