Unit activity of ventral horn cells in spinal cord slices isolated from adult rats.
Using spinal cord slices isolated from adult rats, unitary action potentials were recorded extracellularly in the motor nuclei of the ventral horn following local stimulation of the adjacent site. Generation of these spikes was blocked by perfusion with artificial cerebrospinal fluid containing low Ca2+ and high Mg2+ and by increasing the frequency of electrical stimulation. Generation of unitary action potentials was very sensitive to hypoxia or anesthesia. In some cells, burst spikes similar to those of Renshaw cells were also observed. Physostigmine increased the firing rate of spike discharges, whereas mecamylamine decreased it. These results suggest that the former unitary action potentials were evoked transsynaptically in motoneurons by excitation of adjacent afferent fibers and that the latter burst potentials were evoked in Renshaw cells.
Hirayama
T
T
Department of Toxicology and Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Ono
H
H
Fukuda
H
H
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002413:Cations, Divalent / Q000494:pharmacology; D004558:Electric Stimulation; D008297:Male; D008464:Mecamylamine / Q000494:pharmacology; D009046:Motor Neurons / Q000187:drug effects / Q000502:physiology*; D010830:Physostigmine / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000166:cytology / Q000187:drug effects / Q000502:physiology*
D002413:Cations, Divalent; D008464:Mecamylamine; D010830:Physostigmine