Neurobiology of aging
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Neurobiology of aging · Sep 1991
Age-related decline of vasopressin mRNA in the bed nucleus of the stria terminalis.
To determine whether aging influences arginine vasopressin (AVP) biosynthesis in the extrahypothalamic neurons of the bed nucleus of the stria terminalis (BNST), we used in situ hybridization and quantitative autoradiography to compare AVP mRNA in 3-month-old, 14-month-old, and 24-month-old male Fischer 344 rats. As AVP synthesis in the BNST has previously been shown to be steroid-dependent, plasma testosterone (T) was measured by radioimmunoassay. ⋯ Plasma T was also significantly lower in 24-month-old animals when compared with 3-month (p less than 0.01) or 14-month (p less than 0.05) groups. The results indicate that there is a marked age-related decline in vasopressin biosynthetic activity in neurons of the BNST.
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Neurobiology of aging · Sep 1988
Animal models of age- and disease-related cognitive decline: perspectives on the models and therapeutic strategies.
The relative value of animals with memory impairments, due either to experimental lesions or aging processes, is dependent upon the specific hypothesis being tested. The experimental approaches described in the preceding reviews are valuable for basic studies on learning and memory in the mammalian brain. However, because of important differences between available model systems and human disease states, such as Alzheimer's disease, their use at present may be insufficient for understanding and developing treatment strategies for human cognitive dysfunctions. In this commentary, different aspects of animal models of memory dysfunction will be discussed relative to their ability to assess the structural and functional consequences of central nervous system (CNS) repair.
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Neurobiology of aging · Jan 1985
Interaction of norepinephrine with Purkinje cell responses to cerebellar afferent inputs in aged rats.
Age-related differences in the modulatory actions of NE on the evoked activity of cerebellar Purkinje cells were examined in young (3 month) and old (18-20 month) Fischer 344 rats. We have previously shown that NE is more potent in young than in old rats, in terms of its ability to inhibit spontaneous activity. In this investigation complex spike excitation, simple spike excitation, and inhibition of Purkinje cell discharge were elicited by stimulation of climbing fibers, mossy fibers, and cerebellar parallel fibers, and quantified by computing post-stimulus time histograms of the neuronal response, recorded extracellularly. ⋯ The inhibitory response of the Purkinje cell to activation of basket and stellate cell afferents is potentiated by NE with respect to the inhibition of spontaneous discharge. In old rats the NE-induced potentiation of both excitatory and inhibitory responses was significantly diminished. The loss of noradrenergic enhancement of the relative responsiveness of Purkinje neurons to afferent inputs in senescent animals may relate to behavioral deficits seen in aging.