Racine scores were determined as described in Methods (experimental protocol in Fig. 2A). The symbols are the mean ± SEM of the scores for 10-min observation periods. The vertical lines labeled 1, 2, and 3 indicate the time of the three injections for each group. PI-DFP: (1) pyridostigmine, (2) ipratropium, and (3) DFP. PIW: (1) pyridostigmine, (2) ipratropium, and (3) water. SSW: (1) saline, (2) saline, and (3) water.