Fig. 2. Dose–response relations of tetracaine-induced growth cone collapse. Growth cone collapse percentage was examined at 60 min after tetracaine exposure (A ) and at 24 h after the exposure (B ). One-way analysis of variance for repeated measurements indicated that three dose–response curves at each time point were significantly different from each other (P < 0.01). *¶Significantly different from the corresponding value of retinal neurons (*P < 0.05, ¶P < 0.01). #†Significantly different from the corresponding value of sympathetic neurons (#P < 0.05, †P < 0.01). Values are mean ± SD. DRG = dorsal root ganglion neurons; RET = retinal ganglion cell layer neurons; SYMP = lumbar sympathetic chain neurons.