Immediate consequences of spinal cord injury: possible role of potassium in axonal conduction block.

Compression injury of the spinal cord of cats produced increased outflux of potassium from the damaged site. Conduction by large axons in sensory pathways of the spinal cord was blocked partially by bathing the cord in solutions containing potassium concentrations of the order of 50-100 mEq/liter. It is suggested that block by increased K+ concentration in the extracellular space could interfere with long tract function immediately after cord injury before the onset of gross structural changes, and that increased extracellular potassium may be a link in the mechanisms producing thses later changes.