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. Author manuscript; available in PMC: 2023 May 10.
Published in final edited form as: Neuropharmacology. 2022 Jan 24;208:108976. doi: 10.1016/j.neuropharm.2022.108976

Fig. 6. Experiment 1: Extended effects of repeated dopamine system agonism on mechanical hypersensitivity in rats with chronic inflammatory pain.

Fig. 6.

(A) At three-days post-repeated l-DOPA treatment, there was an effect of CFA treatment (p < 0.0001) on paw withdrawal thresholds and an interaction (p < 0.01), but no effect of l-DOPA treatment (p > 0.05). Post hoc analysis revealed that paw withdrawal thresholds of CFA-vehicle (****p < 0.0001) and CFA-l-DOPA (*p < 0.05) animals were decreased compared to saline-vehicle animals. There was an increase in paw withdrawal thresholds of CFA-l-DOPA animals compared CFA-vehicle animals (#p < 0.05). This suggests that l-DOPA treatment increases paw withdrawal thresholds and reduces mechanical hypersensitivity in CFA animals three days after repeated administration. (B) At three-days post-repeated pramipexole treatment, there was an effect of CFA treatment (****p < 0.0001) on paw withdrawal thresholds, but no effect of pramipexole treatment (p > 0.05). (C) At one-week post-repeated l-DOPA treatment, there was an effect of CFA treatment (****p < 0.0001) on paw withdrawal thresholds, but no effect of l-DOPA treatment (p > 0.05). (D) At one-week post-repeated pramipexole treatment, there was an effect of CFA treatment (****p < 0.0001) and pramipexole treatment (*p < 0.05) on paw withdrawal thresholds. This suggests that pramipexole treatment increases paw withdrawal thresholds one week after repeated administration. (E) At two-weeks post-repeated l-DOPA treatment, there was an effect of CFA treatment (****p < 0.0001) on paw withdrawal thresholds, but no effect of l-DOPA treatment (p > 0.05). (F) At two-weeks post-repeated pramipexole treatment, there was an effect of CFA treatment < 0.0001) on paw withdrawal thresholds, but no effect of pramipexole treatment (p > 0.05). Bars represent means and symbols represent individual data points.