title: Role of glucose or potassium lack in nerve block.
abstract: Potassium and glucose are usually lacking in solutions employed for nerve conduction block. The significance of this for impulse conduction was studied in rabbit vagus nerve in vitro, incubated for 2 h Ringer's bicarbonate solution containing or lacking 5 mM glucose and 4 mM potassium chloride (n = 5 for each conditions). The c-fiber actin 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 potassium-free medium lost 20 per cent of their potassium. In the absence of glucose, reversible extinction of conduction was complete in 78 +/- 9 min when external potassium was present, and in 110 +/- 10 min when external potassium was absent. The data suggest that lack of glucose may reinforce C-fiber inexcitability during conduction block and that inclusion of a physiologic amount of potassium chloride in the solution may also be desirable.
mesh_terms: D000818:Animals; D005947:Glucose / Q000494:pharmacology*; D009407:Nerve Block; D009412:Nerve Fibers / Q000187:drug effects; D009431:Neural Conduction / Q000187:drug effects*; D011189:Potassium Chloride / Q000494:pharmacology*; D011817:Rabbits; D014630:Vagus Nerve / Q000187:drug effects
chemical_list: D011189:Potassium Chloride; D005947:Glucose