Figure 7. After stable recordings in bicarb/7.6 solution without procaine, axons were perfused for 15 min with 1 mM procaine dissolved in either bicarb/7.6, nonbicarb/7.6, or nonbicarb/8.0 solution, and intracellular concentrations of procaine were determined. In another set of experiments, electrically elicited action potentials were measured in the same condition, converted to dV/dt, and determined the maximum value as dV/dt^max. Means +/- SD. *P < 0.05. **P < 0.01.