Role of excitatory amino acids in brainstem activation of spinal locomotor networks in larval lamprey.
An in vitro brain/spinal cord preparation from larval lamprey was used to determine the role of excitatory amino acid (EAA) receptors in the descending activation of spinal locomotor networks. The general EAA receptor blockers KYN, PDA, and DGG completely blocked locomotor activity initiated from the brainstem. The NMDA receptor blocker APV and the non-NMDA receptor blocker DNQX usually attenuated but did not block locomotor activity. Relatively long and short cycle times were attenuated about equally by APV or DNQX, and therefore the attenuation was not cycle time dependent. Receptor blockers for EAAs attenuated locomotor activity, but often with little or no change in the cycle time of burst activity. Although both NMDA and non-NMDA receptors for EAAs are important for the descending initiation of locomotor activity in the lamprey, it is unclear whether these receptors are concentrated in areas of the spinal locomotor networks that control cycle time.
Hagevik
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Division of Biological Sciences, University of Missouri, Columbia 65211.
McClellan
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D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001933:Brain Stem / Q000187:drug effects*; D007736:Kynurenic Acid / Q000494:pharmacology; D007798:Lampreys / Q000502:physiology*; D007814:Larva; D008124:Locomotion / Q000187:drug effects / Q000502:physiology*; D009415:Nerve Net / Q000187:drug effects*; D011810:Quinoxalines / Q000494:pharmacology; D017459:Receptors, Amino Acid / Q000037:antagonists & inhibitors; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology*; D013268:Stimulation, Chemical
D000596:Amino Acids; D011810:Quinoxalines; D017459:Receptors, Amino Acid; C056723:FG 9041; D015763:2-Amino-5-phosphonovalerate; D007736:Kynurenic Acid