Abstract Title:

Homocysteine excess: delineating the possible mechanism of neurotoxicity and depression.

Abstract Source:

Fundam Clin Pharmacol. 2015 Aug 27. Epub 2015 Aug 27. PMID: 26376956

Abstract Author(s):

Pankaj Bhatia, Nirmal Singh

Article Affiliation:

Pankaj Bhatia


Homocysteine (Hcy) is a nonproteogenic sulfur containing amino acid derived from dietary methionine through demethylation. Homocysteine can be re-methylated to methionine [precursor of S-adenosylmethionine (SAM)] via the re-methylation or 5-methyltetrahydrofolate pathway or undergoes transsulfuration to form cysteine by the action of metabolic enzymes and cofactors. Impaired metabolism due to genetic alteration in metabolic enzymes (methionine synthase, methyltetrahydrofolate reductase (MTHFR), cystathionineβ-synthase (CβS), and cystathionine-γ-lyase (CγL) or deficiency in cofactors (vitamin B6 , B12 , folate) may lead to acquired metabolic anomaly known as hyperhomocysteinemia. Hcy excess decreases the S-adenosylmethionine (SAM)-dependent synthesis of catecholamines, viz. dopamine, norepinephrine,epinephrine, and noncatecholamine, viz. serotonin (5-HT), due to genetic alteration in key enzyme MTHFR in the homocysteine metabolism pathway that leads to depression. Thus, hyperhomocysteinemia (HHcy)-induced SAM level is influenced by the single nucleotide polymorphism (SNP) MTHFR C677T. Furthermore, HHcy leads to production of precarious neurotoxic product homocysteic acid (HCA) and cysteine sulfinic acid (CSA) which acts as an N-methyl-D-aspartate (NMDA) receptor agonist and has neurotoxic effects on dopaminergic neurons. In the current review, an attempt has been made to discuss the neurotoxic effects of HHcy in the pathogenesis of depression.

Study Type : Review

Print Options

Sayer Ji
Founder of GreenMedInfo.com

Subscribe to our informative Newsletter & get Nature's Evidence-Based Pharmacy

Our newsletter serves 500,000 with essential news, research & healthy tips, daily.

Download Now

500+ pages of Natural Medicine Alternatives and Information.

This website is for information purposes only. By providing the information contained herein we are not diagnosing, treating, curing, mitigating, or preventing any type of disease or medical condition. Before beginning any type of natural, integrative or conventional treatment regimen, it is advisable to seek the advice of a licensed healthcare professional.

© Copyright 2008-2023 GreenMedInfo.com, Journal Articles copyright of original owners, MeSH copyright NLM.