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Summary: Noncholinergic excitatory actions of motoneurons
in the neonatal mammalian spinal cord
George Z. Mentis*
, Francisco J. Alvarez
, Agnes Bonnot*, Dannette S. Richards
, David Gonzalez-Forero
,
Ricardo Zerda
, and Michael J. O'Donovan*
*Laboratory of Neural Control, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892; and Department
of Anatomy and Physiology, Wright State University, Dayton, OH 45435
Communicated by Lynn T. Landmesser, Case Western Reserve University, Cleveland, OH, April 7, 2005 (received for review February 11, 2005)
Mammalian spinal motoneurons are considered to be output
elements of the spinal cord that generate exclusively cholinergic
actions on Renshaw cells, their intraspinal synaptic targets. Here,
we show that antidromic stimulation of motor axons evokes
depolarizing monosynaptic potentials in Renshaw cells that are
depressed, but not abolished, by cholinergic antagonists. This
residual potential was abolished by 2-amino-5-phosphonovaleric
acid and 6-cyano-7-nitroquinoxaline-2,3-dione. In the presence of
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