Neuroscience
-
We assessed the effect of 3h of environmental enrichment (EE) exposure per day started at different ages (3 and 18months old) on the performance in a spatial memory task and on brain regions involved in the spatial learning (SPL) process using the principal component analysis (PCA). The animals were tested in the four-arm radial water maze (4-RAWM) for 4days, with six daily trials. We used cytochrome c oxidase (COx) histochemistry to determine the brain oxidative metabolic changes related to age, SPL and EE. ⋯ Respect to COx histochemistry results, we found that different brain mechanisms are triggered in aged rats to solve the spatial task, compared to young rats. PCA revealed the same brain functional network in both age groups, but the contribution of the brain regions involved in this network was slightly different depending on the age of the rats. Thus, in the aged group, brain regions involved in anxiety-like behaviour, such as the amygdala or the bed nucleus of the stria terminalis had more relevance; whereas in the young enriched group the frontal and the hippocampal subregions had more contribution.
-
Recent studies indicate that adiponectin can attenuate cerebral ischemic lesions via its functional area located in the C-terminal globular domain, which is called globular adiponectin (gAD). However, the mechanisms underlying this action remain unclear. In this study, we investigated the antioxidant properties of gAD during cerebral ischemia. ⋯ Furthermore, the activities of SOD and catalase increased, and the content of MDA reduced. However, TBCA blocked the effect of gAD on cerebral protection and its antioxidant abilities. Taken together, these results demonstrate that the neuroprotective action of gAD may result from the promotion of antioxidant capacity by inhibiting the NOX2 signaling system.
-
To examine the effect of glucose on the cerebral metabolism of glutamine, rat brain slices were incubated with 5mM [3-(13)C]glutamine without and with 5mM unlabeled glucose. Tissue plus medium extracts were analyzed by using enzymatic and (13)C NMR techniques and fluxes through the enzymatic steps involved were calculated with a mathematical model. ⋯ The results indicate that 77% of the newly appeared glutamine was formed via glutamine synthetase and 23% from endogenous sources; the stimulation of [3-(13)C]glutamine removal by MSO also strongly suggests the existence of a cycle between [3-(13)C]glutamine and [3-(13)C]glutamate. This work also demonstrates that glucose increased fluxes through hexokinase, pyruvate kinase, lactate dehydrogenase, alanine aminotransferase, pyruvate carboxylase, pyruvate dehydrogenase, citrate synthase, flux from α-ketoglutarate to glutamate and flux through glutamine synthetase whereas it inhibited fluxes through aspartate aminotransferase, glutamic acid decarboxylase and GABA aminotransferase.
-
Acoustic trauma, a leading cause of sensorineural hearing loss in adults, induces a complex degenerative process in the cochlea. Although previous investigations have identified multiple stress pathways, a comprehensive analysis of cochlear responses to acoustic injury is still lacking. In the current study, we used the next-generation RNA-sequencing (RNA-Seq) technique to sequence the whole transcriptome of the normal and noise-traumatized cochlear sensory epithelia (CSE). ⋯ Moreover, protein expression analysis revealed strong expression of Cfi and C1s proteins in the organ of Corti. Importantly, these proteins exhibited expression changes following acoustic trauma. Collectively, the results of the current investigation suggest the involvement of the complement components in cochlear responses to acoustic trauma.
-
This study characterizes the different response patterns of sleep and wakefulness (W) to short light-dark (LD) cycles in albino mice and examines whether retinal degeneration resulting from prolonged bright light treatment and/or rd/rd mutation alters such response patterns. Eight young male Institute for Cancer Research (ICR) mice with normal eyes, seven young male rd/rd Friend Virus B type (FVB) mice, six young ICR and five young rd/rd FVB mice receiving 48-h bright light treatment, and five older rd/rd FVB mice were implanted with skull and muscle electrodes to record sleep and W. All the mice were maintained in 12-h-12-h LD cycles at baseline and received 2 days of short LD cycle treatment, which included 5-min-5-min LD cycles for a total of 24 cycles presented 4h after lights-on and again 4h after lights-off. ⋯ Retinal degeneration rising from bright light treatment and/or genetic mutation failed to eliminate or reduce the response of PS and NREMS to short LD cycles, although it enhanced the LD contrast of W, i.e., bright light treatment prolonged the alerting effect of light and the rd mutation increased the suppressing effect of the dark on W. These results suggest that sleep responses to short LD cycles and the brief alerting effect of light were independent of the photoreceptors in the outer retina. Furthermore, the residual photoreceptors in the outer retina and/or the photosensitive cells in the inner retina may actively modulate the effect of light and dark signals on W.