Sandyk R
Department of Neuroscience, Touro College, Dix Hills, NY 11746, USA.
Int J Neurosci. 1997 Aug;90(3-4):271-5. doi: 10.3109/00207459709000643.
Hypotheses pertaining to the etiology of Parkinson's disease (PD) have suggested that the disease reflects an accelerated form of the normal aging process. Aging is associated with progressive failure of the pineal gland associated with a gradual decline in nighttime plasma melatonin secretion. The decline in melatonin secretion with age, at an average rate of 10-15% per decade, is considered a marker of brain aging in humans and estimations of plasma melatonin levels could be used to distinguish the processes of normal aging from pathological age-related changes. The accelerated aging hypothesis of PD is not supported by studies which have examined nocturnal melatonin secretion in drug naive Parkinsonian patients compared to age matched normal control subjects. Specifically, these studies have revealed no significant differences in the melatonin rhythms (i.e., peak nocturnal melatonin level and 24-hour melatonin output) between PD patients and normal age matched controls. On the other hand, melatonin secretion is significantly lower in Alzheimer's patients compared to age matched normal subjects. Collectively, it is suggested, on the basis of melatonin circadian rhythms, that Alzheimer's disease rather than PD is related to an accelerated aging process, a hypothesis which is supported by pathological and neurochemical studies.
关于帕金森病（PD）病因的假说表明，该疾病反映了正常衰老过程的一种加速形式。衰老与松果体的进行性功能衰退有关，这与夜间血浆褪黑素分泌的逐渐减少相关。随着年龄增长，褪黑素分泌以每十年10 - 15%的平均速率下降，这被认为是人类大脑衰老的一个标志，血浆褪黑素水平的评估可用于区分正常衰老过程与病理性年龄相关变化。与年龄匹配的正常对照受试者相比，对未用药的帕金森病患者夜间褪黑素分泌进行研究的结果并不支持PD的加速衰老假说。具体而言，这些研究表明，PD患者与年龄匹配的正常对照之间的褪黑素节律（即夜间褪黑素峰值水平和24小时褪黑素分泌量）没有显著差异。另一方面，与年龄匹配的正常受试者相比，阿尔茨海默病患者的褪黑素分泌显著更低。总体而言，基于褪黑素昼夜节律表明，阿尔茨海默病而非PD与加速衰老过程相关，这一假说得到了病理学和神经化学研究的支持。
