Medical University of Plovdiv, Plovdiv, Bulgaria.
Folia Med (Plovdiv). 2021 Jun 30;63(3):377-384. doi: 10.3897/folmed.63.e55136.
Parkinson's disease (PD) is а neurodegenerative disorder characterized mainly by its motor symptoms. The non-motor symptoms including pain are increasingly recognized in the last few decades. Existing evidence suggests that the dopaminergic neurotransmission has an essential role in pain control.
The aim of the present study was to investigate the antinociceptive effect of dopaminergic drugs pramipexole and tolcapone against chemical and thermal stimuli in naive rats.
Male Wistar rats divided into 8 groups (n=8): saline; diclofenac 25 mg/kg body weight (bw) (positive control); pramipexole 0.5; 1 and 3 mg/kg bw; tolacapone 5; 15 and 30 mg/kg bw. Paw pressure and plantar tests were performed. Paw withdrawal pressure and latent time were measured. Statistical analysis was done by SPSS 19.
In the paw pressure test, pramipexole, in a dose of 1 and 3 mg/kg bw and tolcapone in a dose of 30 mg/kg bw, increased significantly the latency at 1, 2, and 3 hours compared to saline (p<0.05). In the plantar test, only the highest dose of pramipexole reached significance at 3 hours compared to the control rats (p<0.05). In contrast to pramipexole the three experimental groups with tolcapone markedly increased the latent time at 1 and 3 hours compared to saline (p<0.05).
Pramipexole and tolcapone reduce mechanical and thermal nociception in naïve rats by enhancing dopaminergic neurotransmission at both spinal and supraspinal levels. In addition, tolcapone stimulates noradrenergic mediation which may contribute to its antinociceptive effect.
帕金森病（PD）是一种主要表现为运动症状的神经退行性疾病。在过去几十年中，越来越多的人认识到非运动症状包括疼痛。现有证据表明，多巴胺能神经传递在疼痛控制中起着至关重要的作用。
本研究旨在探讨多巴胺能药物普拉克索和托卡朋对化学和热刺激在未处理大鼠中的镇痛作用。
雄性 Wistar 大鼠分为 8 组（n=8）：生理盐水；双氯芬酸 25mg/kg 体重（BW）（阳性对照）；普拉克索 0.5、1 和 3mg/kg BW；托卡朋 5、15 和 30mg/kg BW。进行爪压力和足底测试。测量爪回缩压力和潜伏期。统计分析采用 SPSS 19 进行。
在爪压力试验中，普拉克索在 1 和 3mg/kg BW 剂量下，以及托卡朋在 30mg/kg BW 剂量下，与生理盐水相比，1、2 和 3 小时时潜伏期显著增加（p<0.05）。在足底试验中，只有普拉克索的最高剂量在 3 小时时与对照大鼠相比达到显著性差异（p<0.05）。与普拉克索相反，托卡朋的三个实验组在 1 和 3 小时时明显增加了潜伏期，与生理盐水相比（p<0.05）。
普拉克索和托卡朋通过增强脊髓和脊髓上水平的多巴胺能神经传递，减轻未处理大鼠的机械和热痛觉。此外，托卡朋刺激去甲肾上腺素能介导，这可能有助于其镇痛作用。
