Bahri AYDIN, Hasan Ali TUFAN, Şafak KORKMAZ, Feyzahan EKİCİ

Magnesium: Effect on ocular health as a calcium channel antagonist

Magnezyum hücre zar fonksiyonlarını, düz kas kontrak-siyonlarını ve enzimatik reaksiyonları etkileyerek pekçok metabolik sürece katılan fizyolojik bir kalsiyum kanal blokörüdür. Magnezyumun Endothelin-1 (ET-1) ve NitrikOksit (NO) yolakları vasıtasıyla endotel fonksiyonlrını modifiye ederek dokulara kan akımında artışa neden olduğu gösterilmiştir. Magnezyum aynı zamanda N-me- til-D-aspartat (NMDA) reseptör ilişkili kalsiyum içe akımı- nı bloke ederek ve glutamat serbestleşmesini önleyereknöroprotektif rol oynamakta ve hücreleri oksidatif stres veapoptoza karşı korumaktadır. Hem kan akımında artışa neden olması hem de nöroprotektif etkileri magnezyumuglokom çalışmaları için iyi bir hedef molekül yapmaktadır. Magnezyumun retinada oksidatif stresi ve apoptozu azalt-tığı ve ganglion koruyucu etkileri olduğu gösterilmiştir. Bir takım çalışmalarda aynı zamanda magnezyumun diabe- tik hastalarda insulin resistansını azalttığı, glisemik kont- rolü kolaylaştırdığı ve retinopatiyi önlediği gösterilmiştir. Magnezyumun lensteki iyon dengesinin sağlanmasındakritik önemi belirlenmiştir. Magnezyum eksikliğinin lentiküler oksidatif stresi arttırdığı ve iyon dengesini bozarak katarakt oluşumuna neden olduğu gösterilmiştir.

Magnezyum: Kalsiyum kanal antagonisti olarak göz sağlığı üzerindeki etkileri

Magnesium is the physiologic calcium channel blocker,involving in many different metabolic processes by main-taining cell membrane function, modulating smooth mus-cle contraction and influencing enzymatic activities. Mag-nesium has been shown to increase blood flow to tissuesby modifying endothelial function via endothelin-1 (ET-1)and nitric Oxide (NO) pathways. Magnesium also exhib-its neuroprotective role by blocking N-methyl-D-aspartate(NMDA) receptor related calcium influx and by inhibitingthe release of glutamate, hence protects the cell againstoxidative stress and apoptosis. Both increase in bloodflow and its neuroprotective effect make magnesium agood candidate for glaucoma studies. Magnesium hasbeen shown to decrease oxidative stress and apoptosisin retinal tissue and to have retinal ganglion cell spar-ing effect. A series of studies has been conducted aboutmagnesium could decrease insulin resistance in diabeticpatients, ease glycemia control and prevent diabetic reti-nopathy. Magnesium is found to be critically important inmaintaining normal ionic homeostasis of lens. Magnesiumdeficiency has been shown to cause increased lenticularoxidative stress and ionic imbalance in the lens so triggercataractogenesis.

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