Age-dependent alterations in mitochondrial enzymes in cortex, striatum and hippocampus of rat brain ? potential role of L-Carnitine

Abstract

Mitochondria link the energy -- releasing activities of electron transport and proton pumping with the energy conserving process of oxidative phosphorylation to form ATP. A declined mitochondrial performance has been generally observed during aging. In the present investigation, the activities of tricarboxylic acid cycle enzymes such as isocitrate, alpha-ketoglutarate, succinate and malate dehydrogenases and electron transport complexes I-IV were measured in mitochondria isolated from brain regions like cortex, striatum and hippocampus of young and aged rats before and after L-Carnitine supplementation. All the three brain regions of aged rats showed decreased activities of isocitrate, alpha-ketoglutarate and succinate dehydrogenases, complexes I and IV when compared to control young rats. Striatum seems to be the most susceptible region when compared to hippocampus and cortex. L-Carnitine supplementation to aged rats reversed the activities of these enzymes to near normal whereas treatment to young rats did not show any significant alterations. These results confirm that L-Carnitine can alleviate the age-associated decline in the metabolic efficiency of mitochondria in all three brain regions under investigation.

L-carnitine prevents memory impairment induced by chronic REM-sleep deprivation

“…In the literature, few studies were performed to evaluate the effect of L-CAR on learning and memory deficits induced by different pathological conditions. L-CAR exhibits antioxidant properties [26,55], and several studies showed that carnitine exhibits neuroprotective effects in aging animals [53]. A study showed that aged rats treated with L-CAR exhibited improvement in the levels of SOD, catalase, and GPx [46].…”

Mitochondria in the elderly: Is acetylcarnitine a rejuvenator?☆

“…OXPHOS in the presence of substrates feeding electrons through complexes I and II decrease in the brain from aged compared to young rats [25]. The activities of complex I [25, 26, 72, 73], complex I+III [21, 74] and complex IV [21, 26, 72–78], and the content in cytochromes c and aa 3 [25] also were reported to decrease during aging.…”

Ganoderma lucidum (Fr.) P. Karst enhances activities of heart mitochondrial enzymes and respiratory chain complexes in the aged rat

“…Preservation of mitochondrial function is important for maintaining overall health during aging. In order to protect the mitochondria against respiration-linked oxidative stress, and to preserve the genomic and structural integrity of these energyproducing organelles dietary supplementation with antioxidants, such as vitamins, N-acetyl cysteine, DL-a-lipoic acid and L-carnitine has been suggested (Chow 1991;Arivazhagan et al 2001;Haripriya et al 2004). The heart is one of the organs, which highly depends on oxidative energy generated in mitochondria, by fatty acid b-oxidation, respiratory electron chain and oxidative phosphorylation (Cadenas and Davies 2000;Marin-Garcia and Goldenthal 2002;Arai et al 2003).…”