Spontaneous activity induced in isolated mouse spinal cord by high extracellular calcium and by low extracellular magnesium.

Published

Journal Article

Spontaneous discharges were observed in recordings from dorsal and ventral roots (DRs and VRs) of hemisected mouse spinal cords in vitro when bath [Ca2+] was raised from the control level of 1.2 to 1.8 or 2.4 mmol/l, and when bath [Mg2+] was lowered resembling drug-induced 'interictal' discharges described earlier. Maximum discharge frequency was reached at 2.4 or 3.6 mmol/l [Ca2+] while at higher concentrations mean frequency diminished but mean amplitude still increased somewhat. The frequency distribution of wave amplitudes suggests recruitment of neurons by groups or assemblies. The pacemaker is located in the dorsal spinal quadrant. The GABAA receptor antagonists picrotoxin and bicuculline in low concentration blocked the spontaneous activity, indicating an obligatory GABAergic link in the pacemaker circuit. The NMDA antagonists D.L-APV and D-APV in high concentration variably depressed but did not abolish spontaneous activity. The propensity of spinal neuron assemblies for self-paced discharge may contribute to the pathologic irritability of injured spinal cords.

Full Text

Duke Authors

Cited Authors

  • Czéh, G; Somjen, GG

Published Date

  • August 21, 1989

Published In

Volume / Issue

  • 495 / 1

Start / End Page

  • 89 - 99

PubMed ID

  • 2570628

Pubmed Central ID

  • 2570628

International Standard Serial Number (ISSN)

  • 0006-8993

Digital Object Identifier (DOI)

  • 10.1016/0006-8993(89)91221-3

Language

  • eng

Conference Location

  • Netherlands