Cham Rakié, Perera Subashan, Studenski Stephanie A, Bohnen Nicolaas I
Department of Bioengineering, University of Pittsburgh, 3700 O'Hara Street, 749 Benedum Hall, Pittsburgh, PA 15213, USA.
Gait Posture. 2007 Oct;26(4):516-25. doi: 10.1016/j.gaitpost.2006.11.204. Epub 2006 Dec 29.
The dopaminergic system of the basal ganglia has been implicated in the integration of sensory information important for balance based on studies in patients with Parkinson's disease. Striatal dopaminergic activity decreases with normal aging.
To investigate the relationship between regional striatal dopaminergic denervation and sensory information integration important for balance in middle-aged and older adults.
Community-dwelling subjects (N=35; age 41-83) with no clinical diagnoses of conditions affecting balance underwent dynamic posturography testing (Sensory Organization Test/SOT) and C-11-beta-CFT dopamine transporter positron emission tomography.
Reduced ventral striatal dopamine was significantly correlated with increased anterior-posterior sway in three SOT conditions. Specifically, during quiet standing (SOT Conditions #1, 2) and when repeatedly to sway-referenced visual environments (SOT Condition #3, Trial #3), pre-synaptic dopaminergic denervation in the anteroventral striatum explained over 20-25% of the variability in sway magnitude above and beyond that explained by age (p<or=0.01). Striatal dopaminergic denervation did not impact balance in sway-referenced floor conditions.
The SOT Condition #3 findings suggest that, in normal aging, the central ability to inhibit balance destabilizing vision-related postural control processes depends at least partially on striatal dopaminergic pathways. In contrast, striatal dopaminergic denervation does not appear to impair the ability to disengage destabilizing proprioceptive inputs and to trigger the vestibular control system during challenging sensory perturbations (SOT Conditions #4-6). Finally, quiet standing results (SOT Conditions #1, 2) justify the need to further investigate the impact of striatal dopaminergic denervation on the ability to tune muscle tone in healthy adults.
基于对帕金森病患者的研究，基底神经节的多巴胺能系统与对平衡至关重要的感觉信息整合有关。随着正常衰老，纹状体多巴胺能活性降低。
研究中年和老年成人区域纹状体多巴胺能去神经支配与对平衡至关重要的感觉信息整合之间的关系。
对35名（年龄41 - 83岁）未患有影响平衡的临床疾病的社区居民进行动态姿势描记测试（感觉组织测试/SOT）和C - 11 - β - CFT多巴胺转运体正电子发射断层扫描。
在三种SOT条件下，腹侧纹状体多巴胺减少与前后摆动增加显著相关。具体而言，在安静站立时（SOT条件#1、2）以及反复面对以摆动为参照的视觉环境时（SOT条件#3，试验#3），腹侧前纹状体的突触前多巴胺能去神经支配解释了摆动幅度变异性的20 - 25%以上，超出了年龄所解释的部分（p≤0.01）。纹状体多巴胺能去神经支配在以摆动为参照的地面条件下不影响平衡。
SOT条件#3的研究结果表明，在正常衰老过程中，抑制与平衡不稳定相关的视觉姿势控制过程的中枢能力至少部分取决于纹状体多巴胺能通路。相比之下，纹状体多巴胺能去神经支配似乎并不损害在具有挑战性的感觉扰动期间（SOT条件#4 - 6）脱离不稳定本体感觉输入并触发前庭控制系统的能力。最后，安静站立的结果（SOT条件#1、2）证明有必要进一步研究纹状体多巴胺能去神经支配对健康成年人调节肌张力能力的影响。
