Yeşil Çayın İki Temel Bileşininin İn Vitro Koşullarda Nöbetle İlişkili Yüksek Frekanslı Osilasyonlar Üzerindeki Etkilerinin Araştırılması

Öz

Amaç: Bu çalışmada, zengin polifenol içeriğiyle nörobiyolojik etkilere sahip olan yeşil çayın iki önemli bileşeni olan epigallokateşin gallat (EGCG) ve L-theaninin, epilepside nöbet belirteci olarak kabul edilen kortikal yüksek frekanslı salınımlar (HFO) üzerindeki etkilerinin araştırılması amaçlanmıştır.
Materyal ve metod: Taze fare beyin kesitlerinde 4-aminopiridin (4-AP, 100 μM) uygulanarak epilepsi benzeri deşarjlar indüklenmiştir. Elektrofizyolojik k ayıtlar a racılığıyla tanımlanan HFO’lar ve 0-40 Hz frekans bandı için güç spektrumu analizleri gerçekleştirilmiştir. HFO’lar; dalgalanma (ripple: 80-200 Hz) ve hızlı dalgalanma (fast ripple: 250-500 Hz) olmak üzere iki alt bantta incelenmiştir. Ardından EGCG (50 μM, n=10) ve L-theanin (50 μM, n=10) uygulanarak güç spektrumlarındaki değişimler izlenmiştir. Bulgular: EGCG uygulaması, nöbet aktivitesiyle ilişkili olan 0-40 Hz frekans bandının gücünü önemli derecede azaltırken, dalgalanma ve hızlı dalgalanma bantlarının gücünü ise önemli ölçüde arttırmıştır. L-theanin uygulaması ise 0-40 Hz ve dalgalanma bantlarının gücünü anlamlı şekilde azaltırken, hızlı dalgalanma bandının gücünü artırmıştır.
Sonuç: HFO’lar, epilepside nöbet odaklarının belirlenmesinde ve epileptogenez mekanizmalarının anlaşılmasında kritik biyobelirteçlerdir. Yeşil çay bileşenleri EGCG ve L-theanin’in bu bantlar üzerinde gösterdiği farklı modülatör etkiler, hücresel düzeyde farklı mekanizmaların devreye girdiğine işaret etmektedir. Bu çalışma, söz konusu bileşenlerin HFO’lar üzerindeki etkisini tanımlayan ilk araştırmadır. Bu sonuçlar anormal nöronal senkronizasyonun diyet veya farmakolojik modülatörlerinin belirlenmesine katkıda bulunabilir.

Anahtar Kelimeler

• Yeşil çay bileşenleri
• yüksek frekanslı salınımlar
• epilepsi

Etik Beyan

Ethical approval was obtained from the Karadeniz Teknik University Animal Research Ethics Committee (approval no: 4, date: November 12, 2025).

Investigation of the Effects of Two Major Green Tea Ingredients on Seizure-Associated High-Frequency Oscillations In Vitro

Öz

Background: This study aimed to investigate the effects of epigallocatechin gallate (EGCG) and L-theanine, two important ingredients of green tea with rich polyphenol content and neurobiological effects, o n c ortical h igh-frequency oscillations (HFOs), which are considered seizure markers in epilepsy. Materials and Methods: Epilepsy-like discharges were induced in fresh mouse brain slices by applying 4-aminopyridine (4-AP, 100 μM). HFOs were identified t hrough electrophysiological recordings, and power analyses were performed for the 0-40 Hz frequency band. HFOs were examined in two sub-bands: ripple (80-200 Hz) and fast ripple (250-500 Hz). Subsequently, changes in power were evaluated after the application of EGCG (50 μM, n=10) and L-theanine (50 μM, n=10).
Results: EGCG administration significantly r educed p ower in the 0-40 Hz frequency band, which is associated with seizure activity, while significantly increasing the power in the ripple and fast ripple bands. L-theanine administration, on the other hand, significantly reduced the power in the 0-40 Hz and ripple bands, while increasing the power in the fast ripple band. Conclusions: HFOs are critical biomarkers in epilepsy for identifying seizure foci and understanding the mechanisms of epileptogenesis. The differing m odulatory e ffects of gr een tea ingredients EGCG and L-theanine on these frequency bands suggest that different mechanisms may be involved at the cellular level. This study is the first to identify the effects of these ingredients on HFOs. These results may contribute to the identification of dietary or pharmacological modulators of abnormal neuronal synchronization.

Anahtar Kelimeler

• Green tea ingredients
• high frequency oscillation
• epilepsy

Etik Beyan

Ethical approval was obtained from the Karadeniz Teknik University Animal Research Ethics Committee (approval no: 4, date: November 12, 2025).

Kaynakça

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