Role of Glucose or Potassium Lack in Nerve Block

Open Access
Publisher Website
Google Scholar
Abstract
K+ and glucose are usually lacking in solutions used for nerve conduction block. The significance of this for impulse conduction was studied in rabbit vagus nerve in vitro, incubated for 2 h in Ringer''s-bicarbonate solution containing or lacking 5 mM glucose and 4 mM KCl (n = 5 for each condition). The C-fiber action potential was recorded by periodic stimulation and the Na+ and K+ content of the desheathed nerve core was determined at the end of the incubation. In the presence of glucose, apparently normal conduction persisted for at least 2 h, even though the nerves incubated in K+-free medium lost 20% of their K+. In the absence of glucose, reversible extinction of conduction was complete in 78 .+-. 9 min when external K+ was present, and in 110 .+-. 10 min when external K+ was absent. Lack of glucose may reinforce C-fiber inexcitability during conduction block and inclusion of a physiologic amount of KCl in the solution may be desirable.

This publication has 2 references indexed in Scilit: