Publication: Absans epilepsili sıçan hipokampusu mossy lif terminallerinde yaşa bağlı gaba değişiklikleri: ultrastrüktürel immünositokimya
Abstract
1. ÖZET Son çalışmalar mossy lif terminallerinin (MLT), hem GABA'yı hem de glutamatı içerdiğini göstermiştir. Bu çalışmada Wistar ve GAERS sıçanlarda, yaşlanma süreci içerisinde (1, 7 ve 18 ay ve üstü) gruplar arası yaş basamaklarında karşılaştırmalı olarak hipokampusun CA3 bölgesindeki MLT'de GABA ve glutamat yoğunluğunu incelemek amaçlanmıştır. Çalışmada 18 ay ve üstü Wistar sıçanların, hipokampal alanının stratum oriens ve stratum lusidum bölgelerinde yoğun bir süngerimsi görüntü verdiği izlenmiştir. Aynı süngerimsi görüntü GAERS sıçanların deneydeki yaş gruplarının hiçbirinde izlenmemiştir. Kontrol sıçanlarda glutamat yoğunluğu yaşlanma süreci içerisinde artmaz iken GAERS yaşlı sıçanlarda anlamlı bir artış gözlenmiştir. Ayrıca veziküler glutamat yoğunluğu tüm yaş dönemlerinde kontrol sıçanlara göre GAERS sıçanlarda anlamlı yüksek bulunmuştur. Veziküler GABA yoğunluğu ise sadece erişkin kontrol sıçanlarda anlamlı bir azalma göstermiştir. Fakat anlamlı GABA artışı 7 ve 18 aylık dönemde kontrol sıçanlara göre GAERS sıçanlarda görülmüştür. Kontrol sıçanların ilerleyen yaş sürecinde gözlenen hipokampal süngerimsi oluşumları nöronal dejenerasyondan çok glial dejenerasyonu yansıtabilir ve bu dejenerasyon yaşlanma ile birlikte nörotransmitter toksisitesine bağlı olabilir. GAERS sıçanlarda, 7 ve 18 aylık dönemde kontrollere göre artan glutamat yoğunluğu ile birlikte görülen GABA yoğunluk artışının GAERS'in 4 aylık döneminde başlayan epileptik aktivite ile birlikte seyreden eksitasyon ve inhibisyon mekanizmalarının dengelenmesini desteklediğini düşünmekteyiz. GABA, GAERS, hipokampus, immünositokimya, yaşa bağlı. 2.
Age-Dependent GABA Changes in Mossy Fiber Terminals of Rat Hippocampus with Absence Epilepsy: Ultrastructural Immunocytochemistry Last studies showed that mossy fiber terminals (MFT) contain both glutamate and GABA. In the present study, it was aimed to investigate GABA and glutamate density in MFTs in the CA3 region of Wistar and GAERS rat hippocampus during aging process (1-, 7- and 18-month-old and older), by comparing the findings of different ages between the groups. In the present study, it was observed that 18-month-old and older Wistar rats showed an intense spongy appearance in the stratum oriens and stratum lucidum layers of the hippocampus. The same spongy appearance were observed in none of the GAERS age groups. Although the glutamate density in control group did not show an increase during aging process, there was a significant increase in old GAERS rats. Besides, vesicular glutamate density at all age periods was found to be significantly increased in GAERS rats compared to control rats. Vesicular GABA density showed a significant decrease only in adult control rats. However, a significant increase in GABA was observed in 7 and 18-month-old GAERS rats compared to the control rats. The hippocampal spongy appearance in control rats during aging process may reflect glial, rather than neuronal, degeneration, and this degeneration may be related to the neurotransmitter toxicity during aging. We think that the increased GABA levels observed together with the increased glutamate levels in 7 and 18-month-old GAERS rats, compared to controls, support the balance between excitation and inhibition mechanisms, seen together with the epileptic activity in GAERS, which start in the postnatal 4 months. Key words: Age-dependent, GABA, GAERS, hippocampus, immunocytochemistry.
Age-Dependent GABA Changes in Mossy Fiber Terminals of Rat Hippocampus with Absence Epilepsy: Ultrastructural Immunocytochemistry Last studies showed that mossy fiber terminals (MFT) contain both glutamate and GABA. In the present study, it was aimed to investigate GABA and glutamate density in MFTs in the CA3 region of Wistar and GAERS rat hippocampus during aging process (1-, 7- and 18-month-old and older), by comparing the findings of different ages between the groups. In the present study, it was observed that 18-month-old and older Wistar rats showed an intense spongy appearance in the stratum oriens and stratum lucidum layers of the hippocampus. The same spongy appearance were observed in none of the GAERS age groups. Although the glutamate density in control group did not show an increase during aging process, there was a significant increase in old GAERS rats. Besides, vesicular glutamate density at all age periods was found to be significantly increased in GAERS rats compared to control rats. Vesicular GABA density showed a significant decrease only in adult control rats. However, a significant increase in GABA was observed in 7 and 18-month-old GAERS rats compared to the control rats. The hippocampal spongy appearance in control rats during aging process may reflect glial, rather than neuronal, degeneration, and this degeneration may be related to the neurotransmitter toxicity during aging. We think that the increased GABA levels observed together with the increased glutamate levels in 7 and 18-month-old GAERS rats, compared to controls, support the balance between excitation and inhibition mechanisms, seen together with the epileptic activity in GAERS, which start in the postnatal 4 months. Key words: Age-dependent, GABA, GAERS, hippocampus, immunocytochemistry.