Neurobiology of disease
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Neurobiology of disease · Jun 2012
Combined inhibition of cell death induced by apoptosis inducing factor and caspases provides additive neuroprotection in experimental traumatic brain injury.
Neuronal programmed cell death (PCD) contributes to delayed tissue damage after traumatic brain injury (TBI). Both caspase-dependent and caspase-independent mechanisms have been implicated, with the latter including apoptosis inducing factor (AIF). The peptidyl-proplyl isomerase Cyclophilin A (CypA) transports AIF from the cytosol to the nucleus, a key step for AIF-dependent cell death. ⋯ Importantly, BAF-treated CypA(-/-) mice, showed greater effects than either intervention alone on multiple outcomes including: reduction in TUNEL-positive cells, decrease in neuroinflammation, improved motor and cognitive recovery, and attenuation of lesion volume and neuronal loss in the hippocampus. Using two in vitro neuronal cell death models known to induce AIF-mediated PCD, we also showed that neurons from CypA(-/-) animals were protected and that effects were unrelated to caspase activation. These data indicate that AIF-mediated and caspase-dependent pathways contribute independently and in parallel to secondary injury after TBI, and suggest that combined therapeutic strategies directed at multiple PCD pathways may provide superior neuroprotection than those directed at single mechanisms.
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Neurobiology of disease · Jun 2012
ReviewCardiovascular dysautonomia in Parkinson disease: from pathophysiology to pathogenesis.
Signs or symptoms of impaired autonomic regulation of circulation often attend Parkinson disease (PD). This review covers biomarkers and mechanisms of autonomic cardiovascular abnormalities in PD and related alpha-synucleinopathies. The clearest clinical laboratory correlate of dysautonomia in PD is loss of myocardial noradrenergic innervation, detected by cardiac sympathetic neuroimaging. ⋯ Alpha-synucleinopathy in autonomic neurons may occur early in the pathogenetic process. The timing of cardiac noradrenergic denervation in PD is therefore a key issue. This review updates the field of autonomic cardiovascular abnormalities in PD and related disorders, with emphasis on relationships among striatal dopamine depletion, sympathetic noradrenergic denervation, and alpha-synucleinopathy.
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Neurobiology of disease · Apr 2012
Imatinib mesylate prevents cerebral vasospasm after subarachnoid hemorrhage via inhibiting tenascin-C expression in rats.
Platelet-derived growth factor (PDGF) has been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH), but the mechanism remains unknown. The purpose of this study was to assess whether imatinib mesylate (imatinib), an inhibitor of the tyrosine kinases of PDGF receptors (PDGFRs), prevents cerebral vasospasm after SAH in rats, and to elucidate if tenascin-C (TNC), a matricellular protein, is involved in the mechanism. Imatinib (10 or 50 mg/kg body weight) was administered intraperitoneally to rats undergoing SAH by endovascular perforation, and the effects were evaluated by neurobehavioral tests and India-ink angiography at 24-72 h post-SAH. ⋯ SAH caused PDGFR-β upregulation, PDGFR activation, mitogen-activated protein kinase activation, and TNC upregulation in the spastic cerebral arteries, all of which were significantly suppressed by imatinib treatment. Recombinant TNC reversed the anti-vasospastic effects and protein expression changes by imatinib. This study suggests that imatinib prevents cerebral vasospasm at least partly via inhibiting the upregulation of TNC, implying that TNC may be a new therapeutic target for post-SAH vasospasm.
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Neurobiology of disease · Apr 2012
Changes in the expression of extracellular regulated kinase (ERK 1/2) in the R6/2 mouse model of Huntington's disease after phosphodiesterase IV inhibition.
The mitogen-activated protein kinases (MAPKs) superfamily comprises three major signaling pathways: the extracellular signal-regulated protein kinases (ERKs), the c-Jun N-terminal kinases or stress-activated protein kinases (JNKs/SAPKs) and the p38 family of kinases. ERK 1/2 signaling has been implicated in a number of neurodegenerative disorders, including Huntington's disease (HD). Phosphorylation patterns of ERK 1/2 and JNK are altered in cell models of HD. ⋯ Conversely, cholinergic and somatostatinergic interneurons of the striatum contain higher levels of pERK in the R6/2 mice compared to the controls. Rolipram induces an increase in pERK expression in these interneurons. Thus, our study confirms and extends the concept that the expression of phosphorylated ERK 1/2 is related to neuronal vulnerability and is implicated in the pathophysiology of cell death in HD.
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Neurobiology of disease · Mar 2012
The beneficial effects of regular exercise on cognition in REM sleep deprivation: behavioral, electrophysiological and molecular evidence.
Inadequate sleep is prevalent in modern societies and is known to profoundly impair cognitive function. We examined the impact of 4 weeks of regular treadmill exercise on sleep deprivation induced spatial learning and memory, synaptic plasticity and related signaling molecules in area CA1 of the rat hippocampus. Rats were exercised on a treadmill and subsequently sleep-deprived for 24h using the modified multiple platform technique. ⋯ Extracellular recording from area CA1 of anesthetized rats revealed that early phase LTP (E-LTP) was markedly impaired in the sedentary sleep deprived animals, but was normal in the exercised sleep deprived group. Additionally, immunoblot analysis of CA1 area before (basal) and after expression of E-LTP indicated that the significant down-regulation of the brain derived neurotrophic factor (BDNF) and phosphorylated calcium-calmodulin dependent protein kinase II (P-CaMKII) levels in sleep deprived animals was prevented by the regular exercise regimen. The results suggest that the regular exercise protocol prevents the sleep deprivation induced impairments in short-term memory and E-LTP by preventing deleterious changes in the basal and post-stimulation levels of P-CaMKII and BDNF associated with sleep deprivation.