Int J Neurosci 2002 Jun;112(6):705-39
Kurup RK, Kurup PA.
Department of Neurology, Medical College Hospital, University of Kerala, Trivandrum, India. firstname.lastname@example.org
Alteration in the isoprenoid metabolites--digoxin, ubiquinone, and dolichol--have been reported in neuronal degeneration (Parkinson's disease), oncogenesis (central nervous system glioma), functional neuropsychiatric disorders (schizophrenia and epilepsy), and immune-mediated disorders (multiple sclerosis).
The coexistence of these disorders has been documented in literature and a central dysfunction related to digoxin and the isoprenoid pathway may underlie all these disorders.
A family with a high prevalence of Parkinson's disease, schizophrenia, neoplasms, syndrome X, rheumatoid arthritis, and epilepsy has been described.
The psychological behavioral patterns of the family were: creativity and high IQ, hypersexual behavior, reduced appetite and eating behavior, insomnia and reduced sleep patterns, increased tendency for spirituality, increased tendency for addiction, less bonding and affectionate behavior, and left handedness/right hemispheric dominance.
Digoxin, an endogenous Na(+)-K+ ATPase inhibitor secreted by the hypothalamus, was found to be elevated and red blood cell (RBC) membrane Na(+)-K+ ATPase activity was found to be reduced in all the disorders and in the indexed family studied.
Hypothalamic digoxin can modulate conscious perception and its dysfunction may lead to schizophrenia.
Digoxin can also preferentially upregulate tryptophan transport over tyrosine, resulting in increased levels of depolarizng tryptophan catabolites, serotonin, quinolinic acid, strychnine, and nicotine, and decreased levels of hyperpolarizing tyrosine catabolites, dopamine, noradrenaline, and morphine, contributing to membrane Na(+)-K+ ATPase inhibition in all the above disorders and the indexed family.
Digoxin-induced membrane Na(+)-K+ ATPase inhibition can result in increased intracellular Ca2+ and reduced Mg2+ levels, leading on to glutamate excitotoxicity, oncogene activation, and immune activation.
Digoxin-induced altered Ca2+/Mg2+ ratios, reduced ubiquinone, and increased dolichol can affect glycoconjugate metabolism, membrane formation and structure, and mitochondrial function, leading to the diverse disorders described above, including those in the indexed family.
The isoprenoid pathway and neurotransmitter patterns were compared in right-handed/LH dominant and left-handed/RH dominant individuals.
The left-handed/RH dominant individuals compared to right-handed/LH dominant individuals had elevated hydroxymethylglutarylcoenzyme A reductase activity, with increased serum digoxin and dolichol levels.
The serum ubiquinone, serum Mg2+ and RBC Na(+)-K+ ATPase activity were reduced in left-handed/RH dominant individuals.
The left-handed/RH dominant individuals compared to right-handed/LH dominant individuals had elevated levels of serum tryptophan, quinolinic acid, serotonin, nicotine, and strychnine.
The levels of tyrosine, dopamine, noradrenaline, and morphine were low in left-handed/RH dominant compared to right-handed/LH dominant individuals.
The hyperdigoxinemic state indicates right hemispheric dominance.
Hypothalamic digoxin can thus function as the master conductor of the neuroimmunoendocrine orchestra and coordinate the functions of various cellular organelles.