Figure 3. Effect of a reduction in [Na⁺]_o on nerve activity in normoxia and hypoxia.

A, perfusate P_O2 and nerve activity before, during and following a 2 min perfusion with an isotonic solution containing a 20 % reduction in [Na⁺]_o, as indicated by the bar. B, same as A but perfusate was moderately hypoxic. C, ratio of nerve activities (means ±s.e.m.) before Na⁺ and following switching to a reduced Na⁺ saline. A reduction in [Na⁺]_o by 20 % caused a significant decrease in discharge frequency during normoxia (P < 0.01, n = 19) and during hypoxia (P < 0.001, n = 19).