Brefel-Courbon Christine, Payoux Pierre, Thalamas Claire, Ory Fabienne, Quelven Isabelle, Chollet François, Montastruc Jean Louis, Rascol Olivier
Service de Pharmacologie Clinique, University Hospital, Toulouse, France.
Mov Disord. 2005 Dec;20(12):1557-63. doi: 10.1002/mds.20629.
Patients suffering from Parkinson's disease (PD) frequently experienced painful sensations that could be in part due to central modification of nociception. We compared pain threshold before and after administration of levodopa in PD patients and in controls, and investigated cerebral activity with positron emission tomography (PET) during experimental nociceptive stimulation. Pain threshold was determined using thermal stimulation during two randomized conditions: off and on. We performed H(2) (15)O PET analysis of regional cerebral blood flow on subjects while they received alternate randomized noxious and innocuous stimuli during off and on conditions. In off condition, pain threshold in nine PD patients was significantly lower than in nine controls. Administration of levodopa significantly raised pain threshold in PD patients but not in controls. During off condition, there was a significant increase in pain-induced activation in right insula and prefrontal and left anterior cingulate cortices in PD compared to control group. Levodopa significantly reduced pain-induced activation in these areas in PD. This study shows that pain threshold is lower in PD patients but returns to normal ranges after levodopa administration. Moreover, PD patients have higher pain-induced activation in nociceptive pathways, which can be reduced by levodopa.
帕金森病（PD）患者经常会经历疼痛感觉，这可能部分归因于伤害感受的中枢性改变。我们比较了帕金森病患者和对照组在服用左旋多巴前后的疼痛阈值，并在实验性伤害性刺激期间使用正电子发射断层扫描（PET）研究了大脑活动。在两种随机条件下使用热刺激来确定疼痛阈值：关期和开期。在关期和开期，当受试者接受交替随机的有害和无害刺激时，我们对其进行了H₂¹⁵O PET分析以测量局部脑血流量。在关期，9名帕金森病患者的疼痛阈值显著低于9名对照组。服用左旋多巴显著提高了帕金森病患者的疼痛阈值，但对对照组没有影响。在关期，与对照组相比，帕金森病患者右侧岛叶、前额叶和左侧前扣带回皮质的疼痛诱发激活显著增加。左旋多巴显著降低了帕金森病患者这些区域的疼痛诱发激活。这项研究表明，帕金森病患者的疼痛阈值较低，但服用左旋多巴后会恢复到正常范围。此外，帕金森病患者在伤害性通路中具有更高的疼痛诱发激活，而左旋多巴可以降低这种激活。
