4,18 Also, normal aging is accompanied by alterations in neuronal calcium homeostasis,8,28 which could be related to oxidation of proteins that are involved in cellular ion homeostasis. This is important, since sustained elevations of intracellular calcium concentrations can cause neuritic degeneration and cell death, and by so doing form the bases for age-related impairments in learning and memory.29 Neurotrophic factors seem to be very much relevant in the aging brain because of their involvement in a high-order of brain plasticity such as learning. #ABT-199 order keyword# In
fact, the expression of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF), in the hippocampus has been reported to decrease with age, and these decreases might contribute to age -related cognitive impairments in rats.1,30,31 Also, a deficit in the expression Inhibitors,research,lifescience,medical of genes that encode for neurotrophic factors that promote neuronal survival, dendritic branching, and outgrowth of synaptic plasticity,
has been shown to be associated with increased cell vulnerability during aging and neurodegenerative diseases.4 With regard to Inhibitors,research,lifescience,medical neurotransmission and aging of the brain, we reported that in the prefrontal cortex the release of dopamine induced by a mild stressor and the increases of dopamine and γ-aminobutyric acid (GABA) in the nucleus accumbens by activation of glutamate receptors decrease with age.1,32,33 Moreover, we have recently proposed that the interaction between neurotransmitters in specific areas of the brain could provide new clues to understanding the age-related changes in specific circuits Inhibitors,research,lifescience,medical of the brain.21,34 For instance, we have found that the interaction between glutamate and dopamine decreases with age in the nucleus accumbens, but not in the dorsal striatum of aged rats.34 These results reinforce the idea already expressed in this review that the effects of aging
on the brain are regionally specific, Inhibitors,research,lifescience,medical and further highlight the relevance of studies to investigate the potential interactions between neurotransmitters in specific neural networks during the normal process of aging.1,34 An experimental setting that provides evidence for Adenosine the plasticity of the brain in both adult and aged animals is referred to as “environmental enrichment.” This will be discussed below. Environmental enrichment and aging of the brain Environmental enrichment refers to an experimental setting in which animals experience enhanced cognitive and social interactions as well as sensory and motor abilities, and this potentiates learning and memory.1 Several studies have shown that this experimental model facilitates the study of plastic changes that occur in the brains of young as well as aged animals.