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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. 5. Experiment 1: Effects of repeated dopamine system agonism on mechanical hypersensitivity in rats with chronic inflammatory pain.

Fig. 5.

(A) For repeated l-DOPA treatment, there was an effect of CFA treatment (****p < 0.0001) on paw withdrawal thresholds and an interaction (p < 0.05), but no effect of l-DOPA treatment (p > 0.05). (B) For repeated pramipexole treatment, there were effects of CFA treatment (p < 0.0001) and pramipexole treatment (****p < 0.0001) on paw withdrawal thresholds, and an interaction (p < 0.05). Post hoc analysis revealed that there was a decrease in paw withdrawal thresholds of CFA-vehicle animals compared to saline-vehicle animals (****p < 0.0001) and an increase in paw withdrawal thresholds of CFA-pramipexole animals compared to CFA-vehicle animals (####p < 0.0001). There was no difference in paw withdrawal thresholds between saline-vehicle and saline-pramipexole animals (p > 0.05). This demonstrates that repeated pramipexole treatment increases paw withdrawal and reduces mechanical hypersensitivity in CFA animals 1 h after repeated administration but produces no analgesic effects in saline animals. There was no difference in paw withdrawal thresholds between saline-vehicle animals and CFA-pramipexole animals (p > 0.05), demonstrating a complete attenuation of pain-like behavior in CFA animal following repeated pramipexole treatment. Bars represent means and symbols represent individual data points.