Kurup Ravi Kumar, Kurup Parameswara Achutha
Department of Neurology, Medical College Hospital, Trivandrum, Kerala, India.
Int J Neurosci. 2003 Apr;113(4):547-63. doi: 10.1080/00207450390162281.
The isoprenoid pathway produces three key metabolites--endogenous digoxin (modulate tryptophan/tyrosine transport), dolichol (important in N-glycosylation of proteins), and ubiquinone (free radical scavenger). It was considered pertinent to assess the pathway in alcoholic addiction, alcoholic cirrhosis, and acquired hepatocerebral degeneration. Since endogenous digoxin can regulate neurotransmitter transport, the pathway and the related cascade were also assessed in individuals with differing hemispheric dominance to find out the role of hemispheric dominance in its pathogenesis. In the patient group there was elevated digoxin synthesis, increased dolichol and glycoconjugate levels, and low ubiquinone and elevated free radical levels. There was also an increase in tryptophan catabolites and a reduction in tyrosine catabolites, as well as reduced endogenous morphine synthesis from tyrosine. There was an increase in cholesterol:phospholipid ratio and a reduction in glycoconjugate level of RBC membrane in these groups of patients. Alcoholic cirrhosis, alcoholic addiction, and acquired hepatocerebral degeneration are associated with an upregulated isoprenoid pathway and elevated digoxin secretion from the hypothalamus. This can contribute to NMDA excitotoxicity and altered connective tissue/lipid metabolism important in its pathogenesis. Endogenous morphine deficiency plays a role in alcoholic addiction. The same biochemical patterns were obtained in those with right hemispheric chemical dominance. Alcoholic addiction, alcoholic cirrhosis, and acquired hepatocerebral degeneration occur in right hemispheric, chemically dominant individuals.
类异戊二烯途径产生三种关键代谢产物——内源性地高辛(调节色氨酸/酪氨酸转运)、多萜醇(在蛋白质的N-糖基化中起重要作用)和泛醌(自由基清除剂)。评估该途径在酒精成瘾、酒精性肝硬化和获得性肝脑变性中的情况被认为是有意义的。由于内源性地高辛可调节神经递质转运,因此还对具有不同半球优势的个体的该途径及相关级联反应进行了评估,以了解半球优势在其发病机制中的作用。在患者组中,地高辛合成增加、多萜醇和糖缀合物水平升高、泛醌水平降低且自由基水平升高。色氨酸分解代谢产物增加,酪氨酸分解代谢产物减少,酪氨酸内源性吗啡合成也减少。这些患者组的红细胞膜胆固醇与磷脂比值增加,糖缀合物水平降低。酒精性肝硬化、酒精成瘾和获得性肝脑变性与类异戊二烯途径上调及下丘脑地高辛分泌增加有关。这可能导致NMDA兴奋性毒性以及在其发病机制中起重要作用的结缔组织/脂质代谢改变。内源性吗啡缺乏在酒精成瘾中起作用。在具有右半球化学优势的个体中也获得了相同的生化模式。酒精成瘾、酒精性肝硬化和获得性肝脑变性发生在右半球化学优势的个体中。