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“Elderly people often develop sleep and autonomic dysfunctions, which are regulated by circadian rhythm. Recently, we reported on the degradation of neural output from the central circadian clock in the suprachiasmatic nucleus (SCN) with aging. However, it is likely that many other factors contribute to the age-related decline in the functioning of the circadian system. In this study, we examined the effects of dopaminergic

neuronal loss in the substantia nigra (SN) on circadian rhythms of mice to assess whether age-related degeneration of the dopamine system influences circadian rhythm. Young male C57BL/6J mice were click here administered 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a compound that selectively destroys dopaminergic neurons in the SN, and their wheel-running activities were recorded. We observed that MPTP-treated mice lost 43% of their dopaminergic neurons in the SN (on average) and

demonstrated longer period of wheel-running activity rhythm in constant darkness compared with control mice. However, all the remaining circadian parameters in the MPTP-treated mice remained constant. Our findings suggest that in addition to SCN check details output dysfunction, age-related degeneration in the dopamine system of the brain leads to circadian rhythm irregularities. (C) 2012 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.”
“Postmortem studies show reductions in brain serotonin 2A (5-HT2A) receptors in Alzheimer’s disease (AD). Converging evidence also suggests that serotonergic dysregulation may contribute to behavioral symptoms that frequently occur in AD. This study aimed to define regional reductions in 5-HT2A binding in AD patients and to examine their behavioral correlates. Nine patients with probable AD and eight elderly controls were studied using a constant infusion paradigm for equilibrium modeling of [F-18]deuteroaltanserin with positron emission tomography (PET). Region of interest analyses were Lenvatinib manufacturer performed on PET images coregistered to MRI scans. The outcome measures

BPP (ratio of specific brain uptake to total plasma parent concentration) and BPND (ratio of specific to nondisplaceable uptake) were obtained for pertinent cortical and subcortical regions. AD patients showed a statistically significant decrease in the anterior cingulate in both BPP and BPND, but in no other region. Within the AD patient sample, no significant correlations were observed between regional 5-HT2A binding and behavioral measures, including depressive and psychotic symptoms. These results confirm a reduction in cortical 5-HT2A receptors in AD, specifically in the anterior cingulate. However, in a limited AD patient sample, they fail to demonstrate a relationship between regional 5-HT2A binding and major behavioral symptoms. (C) 2009 Elsevier Ireland Ltd. All rights reserved.