The effect of changing extracellular potassium concentration on synaptic transmission in isolated spinal cords.

Published

Journal Article

Hemisected spinal cords of infant mice were exposed in vitro to varying concentrations of K+ in the bathing fluid. Interstitial potassium concentration ([K+]o) as well as dorsal and ventral root (DR and VR) potentials evoked by DR stimulation were recorded. [K+]o in spinal tissue was made to change from its control level of 3.5 mM by superfusing the preparation with modified artificial cerebrospinal fluid (ACSF). [K+]o in tissue followed bath [K+] in the range from 2.0 to 13 mM, but diverged from bath concentration at levels at or below 1.0 mM. Relatively high tissue [K+]o during exposure to low bath [K+] was attributed to leakage of K+ ions from cells. Between 2.0 and 5.0 mM [K+]o a shallow but consistent positive correlation was found between [K+]o and dorsal root reflex (DRR) amplitude, while segmental reflex (VRR) amplitude changed little. Outside the range of 2.0-5.5 mM DR and VR responses were severely depressed in both elevated and lowered [K+]o. In spite of depressed reflex responses, transient stimulus-evoked elevations of [K+]o were strikingly increased when the resting [K+]o fell below 2.0 mM, suggesting enhancement of voltage-dependent K+-current.

Full Text

Duke Authors

Cited Authors

  • Czéh, G; Obih, JC; Somjen, GG

Published Date

  • April 1, 1988

Published In

Volume / Issue

  • 446 / 1

Start / End Page

  • 50 - 60

PubMed ID

  • 2836029

Pubmed Central ID

  • 2836029

Electronic International Standard Serial Number (EISSN)

  • 1872-6240

International Standard Serial Number (ISSN)

  • 0006-8993

Digital Object Identifier (DOI)

  • 10.1016/0006-8993(88)91295-4

Language

  • eng