Thyroid hormones: Possible roles in epilepsy pathology. (September 2015)

• Record Type: Journal Article
• Authors: Tamijani, Seyedeh Masoumeh Seyedhoseini; Karimi, Benyamin; Amini, Elham; Golpich, Mojtaba; Dargahi, Leila; Ali, Raymond Azman; Ibrahim, Norlinah Mohamed; Mohamed, Zahurin; Ghasemi, Rasoul; Ahmadiani, Abolhassan
• Is Part Of: Seizure. Volume 31(2015)
• Page Start: 155
• Page End: 164
• Publication Date: 2015-09
• Subjects: Seizures -- Temporal lobe epilepsy (TLE) -- Hyperthyroidism -- Hypothyroidism -- Brain development -- Epileptogenesis; Epilepsy -- Periodicals; Epilepsy -- Periodicals; Seizures -- Periodicals; Épilepsie -- Périodiques; Electronic journals; Electronic journals; 616.853
• DOI: 10.1016/j.seizure.2015.07.021
• Languages: English
• ISSNs: 1059-1311

Abstract

Highlights: Thyroid hormones play essential roles in the brain physiological processes. Epilepsy is accompanied with mitochondrial dysfunction and oxidative stress. Mitochondrial dysfunction and oxidative stress are linked with thyroid dysfunction. Inhibitory/excitatory imbalance is common between epilepsy and thyroid dysfunction. Several genes are influenced by thyroid hormones and are involved in the epilepsy. Abstract: Thyroid hormones (THs) l -thyroxine and l -triiodothyronine, primarily known as metabolism regulators, are tyrosine-derived hormones produced by the thyroid gland. They play an essential role in normal central nervous system development and physiological function. By binding to nuclear receptors and modulating gene expression, THs influence neuronal migration, differentiation, myelination, synaptogenesis and neurogenesis in developing and adult brains. Any uncorrected THs supply deficiency in early life may result in irreversible neurological and motor deficits. The development and function of GABAergic neurons as well as glutamatergic transmission are also affected by THs. Though the underlying molecular mechanisms still remain unknown, the effects of THs on inhibitory and excitatory neurons may affect brain seizure activity. The enduring predisposition of the brain to generate epileptic seizures leads to a complex chronic brain disorder known as epilepsy. Pathologically, epilepsy may be accompanied by mitochondrial dysfunction, oxidative stress and eventually dysregulation of excitatory glutamatergic and inhibitory GABAergic neurotransmission. Based on the latest evidence on the association between THs and epilepsy, we hypothesize that THs abnormalities may contribute to the pathogenesis of epilepsy. We also review gender differences and the presumed underlying mechanisms through which TH abnormalities may affect epilepsy here.