Figure 2. Proprioceptive block of rat sciatic nerve by N-alkyl tetracaine derivatives. On-set (A) and recovery (B) time courses of proprioceptive impairment are expressed as a percentage of maximal possible effect (means +/- SEM) after injection of 0.1 ml drug at 37 mM. Symbols indicate tetracaine (C⁰, [circle, open]; n = 8), N-ethyl tetracaine (C², [open triangle]; n = 8), N-propyl tetracaine (C³, [lozenge, open] n = 14), N-butyl tetracaine (C⁴tetracaine, [round bullet, filled]; n = 14), N-pentyl tetracaine (C⁵, [closed triangle]; n = 7), and N-hexyl tetracaine (C⁶tetracaine, [lozenge, filled]; n = 9). Test intervals for A were before the injection and 5, 10, 30, and 45 min after the injection. Test intervals for B were 0.5, 0.75, 1, 2, 3, 4, 5, 7, 12, 24–26, 48, 168, 336, 504, 672, 840, 1,008, 1,176, and 1,344 h (1 wk = 168 h).