Corticospinal transmission to motoneurons in cervical spinal cord slices from adult rats.
Cervical spinal cord slices were prepared from adult rats. Intracellular recordings from motoneurons revealed that electrical stimulation of the ventralmost part of the dorsal funiculus (which contains primarily descending corticospinal axons) elicited EPSPs in 75% of the neurons. The latencies of these EPSPs tended to be shorter than those elicited by dorsal horn gray matter stimulation. Pairs of subthreshold dorsal funiculus stimuli were able to elicit action potentials in motoneurons. These data are consistent with previous morphological and electrophysiological studies indicating that cervical motoneurons receive both mono-and polysynaptic corticospinal inputs. In addition, motoneurons were markedly depolarized by iontophoretic application of AMPA or KA (7 out of 7 neurons), but only weakly depolarized by NMDA (1 out of 6 neurons). CNQX (but not AP-5) blocked EPSPs elicited by dorsal funiculus stimulation. Thus, corticospinal transmission to motoneurons is mediated primarily by non-NMDA glutamate receptors.
Hori
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School of Public Health, University at Albany, One University Place, Rm. B242 Rensselaer, NY 12144-3456, USA.
Carp
J S
JS
Carpenter
D O
DO
Akaike
N
N
D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000818:Animals; D001369:Axons / Q000502:physiology; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D004594:Electrophysiology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D016202:N-Methylaspartate / Q000494:pharmacology; D011712:Pyramidal Tracts / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D018690:Excitatory Amino Acid Agonists; D018691:Excitatory Amino Acid Antagonists; D016202:N-Methylaspartate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid