Yaşlanma sürecinde melatoninin rolü

Year 2005, Volume: 12 Issue: 3, 52 - 56, 09.04.2009

Hakan Mollaoğlu M.fehmi Özgüner

Abstract

SüleymanDemirel Üniversitesi
TIP FAKÜLTESİ DERGİSİ: 2005 Eylül; 12(3)










Yaşlanma sürecinde melatoninin rolü



Hakan Mollaoğlu, M. Fehmi Özgüner



Özet

Pineal bez çeşitli canlılarda farklı fonksiyonlara sahip bir bez olup fotonöroendokrin kontrol altındadır. Bez özellikle karanlıkta sentezlenen melatonin (N-Asetil-5-Metoksitriptamin) adı verilen bir hormon üretir. Melatonin güçlü bir oksijen radikal toplayıcısıdır ve bu yüzden dokuların hasara uğramasının gecikmesine destek olabilmektedir. Pineal bezden melatonin üretimi insan ve hayvanlarda yaşlanmayla birlikte belirgin olarak azalmaktadır. Yaşlanmayla ilgili kabul gören bir teoriye göre, yaşlanma esnasında organlarda oluşan anatomik ve fonksiyonel dejenerasyon, serbest radikallerin oluşturduğu hasara bağlanmaktadır. Yaşlılıkta

nöronlar veya nöral doku üzerine serbest radikal saldırısı birçok nörodejeneratif durumların oluşumunu kolaylaştırması bakımından önemlidir. Eksitatör aminoasit nörotransmiterler, serbest radikal oluşumuna neden olduğundan dolayı nöronlar üzerine özellikle daha tahripkardır. Bundan dolayı, sinir sonlanmaları ihtiva eden beyin alanları eksitatör aminoasitleri salgıladığından, bu alanlar beynin diğer alanlarına nazaran daha çabuk tahrip olurlar. Yaşlanmayla birlikte, stres veya toksik ajanlara maruz kalma sonucu serbest radikal oluşumunu engelleyen süreçler de tıpkı melatonin seviyelerinde olduğu gibi azalmaktadır. Pineal bez ve melatoninin yıllardır yaşlanmayla ilgili olduğu düşünülmüştür. Melatonin ve yaşlanmayla ilgili birçok

teori öne sürülmüştür. Yaşla ilişkili olarak melatonin seviyesinin azalması ve bu durumun organizmadaki dejenerasyonu ilerletmesi, bütün bu teorilerin dayanak noktalarından birisidir.

Bu bilgiler ışığında melatoninin yaşlılarda ortaya çıkan nörodejeneratif hastalıkların önlenmesinde koruyucu bir rol oynayabileceği düşünülmektedir.



Anahtar kelimeler: melatonin, yaşlanma



Abstract



The role of melatonın durıng agıng

Pineal is a gland that has different functions on various organisms and is under photoneuroendocrine control. The gland produces a hormone called melatonin (N-acetyl 5-methoxitryptamine), which is secreted especially in darkness. Melatonin is a potent free radical scavenger that protects tissues from oxidant damage. Aging in human and animals decreases the production of melatonin by pineal gland obviously. According to an accepted theory about aging, the anatomical and functional degeneration formed in organs while aging is bound to the damage caused by free radicals. In elderly, the free radical attack on neurons or neural tissue is important since aging facilitates the neurodegenerative situations. The excitatory amino acid neurotransmitters, especially, are much more harmful on neurons because they cause the formation of free radicals. For that reason, the brain areas having neuron endings are more likely to be damaged than the other areas of brain are, since they secrete excitatory amino acids. Defense mechanisms to stresses and toxic agents exposure mediated free radicals generations are become insufficient with aging like decreased melatonin production in pineal gland. Pineal gland and melatonin are thought, for years, to be related to aging. Many theories about melatonin and aging have been suggested. The decrease of melatonin levels related to age and this situation, to increase the degeneration in organism is one of the sources of all these theories. In conclusion, melatonin is suggested to play a preservative role in preventing the neurodegenerative disorders becomes in elderly.



Key words: melatonin, aging

Keywords

melatonin, yaþlanma

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