Mechanisms underlying effect of GB34 acupoint in Parkinson’s disease

Although both clinical observation and model studies showed that stimulation of GB34 acupoint improved motor function in Parkinson’s, its mechanism behind is unclear. Very recently two reports of PD model studies shed the light on the question.

Dr. Tian and colleagues in China investigated the effect and mechanism of stimulating GB34 in PD model. They observed first that there was an aggregation of toxic protein, alpha-synuclein closely linked to PD, in the dopamine cells in the brain of PD model. Stimulation at GB34 promoted the autophagic clearance of alpha-synuclein, in a manner different from mammalian target of rapamycin (mTOR)-dependent pathway. Further improvement in the motor function at the behavior level of model was observed. Authors suggested that connection between acupuncture and autophagy not only provides a new route to understanding the molecular mechanism of acupuncture treatment in Parkinson’s.

Later, Dr. Park and colleagues in Korea conducted a series of in vitro and in vivo studies of Parkinson’s. Firstly they found that melanin-concentrating hormone (MCH) in hypothalamus of brain is a neuroprotective agent, then that MCH protected dopamine cells in both vitro and vivo studies. Further stimulation at GB34 activated hypothalamic MCH biosynthesis which can be blocked by MCH-R1 antagonist, then releasing MCH-activated MCH receptors (MCH-Rs) in the dopamine terminals, and showed dopaminergic neuroprotection. MCH is an important metabolic hormone that reportedly influences sleep control and affects learning and memory. About 80 % of patients with PD experienced sleep disturbances, and they showed substantial losses of MCH neurons in the hypothalamus. Moreover, this loss of MCH neurons has been significantly correlated with the clinical stages of PD and regarded as hypothalamic dysfunction in PD. This study suggested that acupuncture stimulation at GB34 activated MCH may play an important role in neuroprotection of Parkinson’s.

References

Tian T et al., Acupuncture promotes mTOR-independent autophagic clearance

of aggregation-prone proteins in mouse brain. Sci Rep. 2016 Jan 21;6:19714.    http://www.nature.com/articles/srep19714

Park JY et al., Novel Neuroprotective Effects of Melanin-Concentrating Hormone in Parkinson’s Disease. Mol Neurobiol. 2016 Nov 14.  https://www.ncbi.nlm.nih.gov/pubmed/27844281