Figure 2. Experimental design.

The figure presents the treatment groups and the protocols used for experiments 1–4. The treatment names are abbreviated as the first letter of each compound, except in the case of DFP and DMSO, where the standard abbreviations are used; the compounds are named in the same sequence as they were injected. The protocols indicate the times of injection of the various drugs as well as the period during which the Racine scores were obtained. In experiments 2–4, the animals were perfused 48 hours after DFP. (A) Experiment 1. Pyridostigmine (P) and ipratropium (I) were injected before DFP in the experimental group PI-DFP; this group tested for the effects of DFP when preceded by pyridostigmine and ipratropium. The PIW group received pyridostigmine, ipratropium, and water (W). Water was the vehicle of DFP; this group tested for the effects of pyridostigmine and ipratropium in the absence of DFP. The SSW group was the all-vehicles control, which received saline (S), saline, and water. (B) Experiment 2 tested for the neuroprotective effect of 4R against DFP. 4R was administered within the PI-DFP paradigm 1 hour before DFP (a. 1h4R-PI-DFP), 5 hours after DFP (b. PI-DFP-5h4R), and 24 hours after DFP (c. PI-DFP-24h4R). The PI-DFP-5hDMSO group tested for the effect of PI-DFP in the presence of DMSO, the vehicle of 4R. The SSW-5hDMSO group was the all-vehicles control. (C) Experiment 3 replicated the study of 4R when injected 1 hour before DFP (1h4R-PI-DFP). The 1 hDMSO-PI-DFP group was the 4R vehicle control. (D) Experiment 4 replicated the study of 4R injected 24 hours after DFP using methyl atropine (M) instead of ipratropium. The experimental group was injected with pyridostigmine and methyl atropine before DFP, followed 24 hours later by 4R (PM-DFP-24h4R). The control group that did not receive 4R (PM-DFP-24hDMSO) was injected 24 hours after DFP with DMSO.