Neuroscience
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Calcitonin gene-related peptide (CGRP) is a powerful pro-inflammatory mediator thought to play a significant role in the development of inflammation and pain. We investigated the role of CGRP in trigeminal inflammatory pain by determining the ability of a monoclonal antibody to CGRP to modify central Fos expression in response to stimulation of the inflamed ferret tooth pulp. We also assessed the effect of the antibody on pulpal inflammation. ⋯ This is the first direct evidence that sequestration of CGRP has anti-inflammatory and putative analgesic effects. Previous studies using this Fos model have demonstrated that it is able to predict clinical analgesic efficacy. Thus these data indicate that this antibody may have analgesic effects in dental pain and other types of inflammatory-mediated transmission, and suggest that this is in part due to peripheral anti-inflammatory effects.
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This study investigated the modular control of complex locomotor tasks that require fast changes in direction, i.e., cutting manoeuvres. It was hypothesized that such tasks are accomplished by an impulsive (burst-like) activation of a few motor modules, as observed during walking and running. It was further hypothesized that the performance in cutting manoeuvres would be associated to the relative timing of the activation impulses. ⋯ The variability in timing between impulses across subjects was greater for cutting manoeuvres than for running. The timing difference between M2 and M3 in the cutting manoeuvres was significantly associated to W-Abs (r(2)=0.45) whereas the timing between M3 and M4 was associated to W-Prp (r(2)=0.43). These results suggest that complex locomotor tasks can be achieved by impulsive activation of muscle groups, and that performance is associated to the specific timing of the activation impulses.
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Comparative Study
Fundamental interstrain differences in cortical activity between Wistar and Sprague-Dawley rats during global ischemia.
Four-vessel occlusion (4VO), a frequently used model of global cerebral ischemia in rats, results in a dysfunction in wide brain areas, including the cerebral cortex and hippocampus. However, there are pronounced differences in response to global ischemia between the laboratory rat strains used in these studies. In the present work, the immediate acute effects of 4VO-induced global ischemia on the spontaneous electrocorticogram (ECoG) signals were analyzed in Wistar and Sprague-Dawley rats. ⋯ These observations clearly demonstrate that the use of different rat strains (e.g. Wistar vs. Sprague-Dawley) can be a source of considerable variability in the results of acute experiments on global ischemia and it is important that the laboratory rats used in such experiments should be carefully chosen.
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Brain development is sensitive to an individual's interaction with its environment. Deprivation of natural environmental stimulation especially in the phase after weaning has long-lasting consequences on neuroplasticity. However, previous findings concerning the effects of rearing environment on adult hippocampal cell proliferation and neurogenesis in rodents remain contradictory. ⋯ Wheel running increased cell proliferation rates in the dentate gyrus of CD1 and C57Bl/6 mice reared under socially and physically deprived conditions, but not from enriched conditions. In wild house mice, neither the rearing conditions nor the wheel-running challenge did affect proliferative activity. This indicates, on the one hand, that wild house mice are more robust in their regulation of hippocampal cell proliferation against environmental influences and, on the other hand, that domestication and rearing background of laboratory animals impact neuroplastic potentials and responsiveness to external stimuli in adulthood.
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To investigate neurofilament (NF) dynamics during the cytoskeleton reorganization in regenerating axons, and their electrophysiological and histological consequences, we used two transgenic lines of mice: neurofilament high (NFH)-LacZ and NFH-green fluorescent protein (GFP). In NFH-LacZ mice, NFs are retained in cell bodies and deficient in axons (Eyer and Peterson, 1994), while in NFH-GFP mice the fluorescent fusion protein is normally transported along axons (Letournel et al., 2006). ⋯ Finally, the axonal transport of NFH-GFP fusion protein and NFs is re-initiated after the crush as evidenced by the fluorescent and immunolabelling of axons distal from the crushed point, but NFs and the fusion protein are not transported along axons during regeneration in NFH-LacZ mice. Together, these results argue that the absence of axonal NFs in NFH-LacZ mice compromises the axonal regeneration, and that the NFH-GFP reporter fusion protein represents an efficient model to evaluate the NF dynamics during axonal regeneration.