Neuropsychiatric symptoms seen in Alzheimer's disease (AD) are not simply a consequence of neurodegeneration, but probably result from differential neurotransmitter alterations, which some patients are more at risk of than others. Therefore, the hypothesis of this study is that an imbalance between the cholinergic and serotonergic systems is related to cognitive symptoms and psychological syndromes of dementia (BPSD) in patients with AD. Cholinergic and serotonergic functions were assessed in post-mortem frontal and temporal cortex from 22 AD patients who had been prospectively assessed with the Mini-Mental State examination (MMSE) for cognitive impairment and with the Present Behavioral Examination (PBE) for BPSD including aggressive behavior, overactivity, depression and psychosis. Not only cholinergic deficits, but also the cholinacetyltransferase/serotonin ratio significantly correlated with final MMSE score both in frontal and temporal cortex. In addition, decreases in cholinergic function correlated with the aggressive behavior factor, supporting a dual role for the cholinergic system in cognitive and non-cognitive disturbances associated to AD. The serotonergic system showed a significant correlation with overactivity and psychosis. The ratio of serotonin to acetylcholinesterase levels was also correlated with the psychotic factor at least in women. It is concluded that an imbalance between cholinergic-serotonergic systems may be responsible for the cognitive impairment associated to AD. Moreover, the major findings of this study are the relationships between neurochemical markers of both cholinergic and serotonergic systems and non-cognitive behavioral disturbances in patients with dementia.
CMS leads to a long-term altered behavioral profile that could be partially reverted by chronic antidepressant treatment. This study brings novel features regarding the long-term effects of CMS and on the predictive validity of this depression animal model.
Pharmacists' knowledge, beliefs, behaviour and motivation play an important role in ADR reporting. Under-reporting might be improved through activities focused on modifying such factors.
Early stressful adverse situations may increase the vulnerability to cognitive deficits and psychiatric disorders, such as depression. Maternal separation (MS) has been used as an animal model to study changes in neurochemistry and behavior associated with exposure to early-life stress. This study investigated the effects of neonatal stress (MS) on the expression of synaptic plasticity markers in the hippocampus and a purported relationship to cognitive processes. Spatial learning (Morris water maze) significantly increased the expression of total levels of the neural cell adhesion molecule (NCAM), as well as its three major isoforms (NCAM-120, -140, and -180) both in the control and MS groups. Interestingly, these increases in NCAM expression after learning were lower in MS animals when compared with control rats. MS induced a significant decrease in total levels of NCAM, and specifically, in the NCAM-140 isoform expression. In the hippocampus of MS rats there was a significant decrease in brain-derived neurotrophic factor and synaptophysin mRNA densities. Cell proliferation, measured as BrdU-positive cells, was also decreased in the dentate gyrus of MS rats. Altogether these results suggest that MS can alter normal brain development, providing a potential mechanism by which early environmental stressors may influence vulnerability to show cognitive impairments later in life.
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