Neuroscience
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The present study was undertaken to investigate the relative contribution of cannabinoid receptors (CBRs) subtypes and to analyze cannabimimetic mechanisms involved in the inhibition of anandamide (AEA) and 2-arachidonoyl glycerol degradation on the antihyperalgesic effect of ankle joint mobilization (AJM). Mice (25-35g) were subjected to plantar incision (PI) and 24h after surgery animals received the following treatments, AJM for 9min, AEA (10mg/kg, intraperitoneal [i.p.]), WIN 55,212-2 (1.5mg/kg, i.p.), URB937 (0.01-1mg/kg, i.p.; a fatty acid amide hydrolase [FAAH] inhibitor) or JZL184 (0.016-16mg/kg, i.p.; a monoacylglycerol lipase [MAGL] inhibitor). Withdrawal frequency to mechanical stimuli was assessed 24h after PI and at different time intervals after treatments. ⋯ Interestingly, in mice pretreated with FAAH or the MAGL inhibitor the antihyperalgesic effect of AJM was significantly longer. This article presents data addressing the CBR mechanisms underlying the antihyperalgesic activity of joint mobilization as well as of the endocannabinoid catabolic enzyme inhibitors in the mouse postoperative pain model. Joint mobilization and these enzymes offer potential targets to treat postoperative pain.
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Electrophysiological properties of lumbar α-motoneurons change after chronic increases and decreases in hindlimb neuromuscular activity. Although modeling of these changes suggests that motoneurons probably alter gene expression in these situations, there is no evidence that this is the case. In this study, we measured the content of several mRNAs in lumbar motoneurons, harvested using laser capture microdissection, from rats previously subjected to normal cage activity, voluntary wheel exercise for 16weeks, and forced treadmill training for 7days and 16weeks. ⋯ Motoneurons from 16-week treadmill-trained rats also did not demonstrate the decreases in several mRNAs that were evident after 7days of treadmill exercise, suggesting an adaptation of motoneurons to acute stress. The mRNA changes following prolonged daily treadmill training are consistent with a reduction in inhibitory influences onto motoneurons, and a transition toward motoneurons that innervate slower contracting muscle fibers. These results demonstrate that the previously reported physiological changes in motoneurons with altered activity are accompanied by changes in gene expression.
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The dopamine (DA), noradrenalin (NA) and serotonin (5-HT) monoaminergic systems are deeply involved in cognitive processes via their influence on cortical and subcortical regions. The widespread distribution of these monoaminergic networks is one of the main difficulties in analyzing their functions and interactions. To address this complexity, we assessed whether inter-individual differences in monoamine tissue contents of various brain areas could provide information about their functional relationships. ⋯ Most correlations found between cortical areas were positive while some cortico-subcortical relationships regarding the DA, NA and 5-HT tissue contents were negative, in particular for DA content. In conclusion, this work provides a useful database of the monoamine tissue content in numerous brain regions. It suggests that the regulation of these neuromodulatory systems is achieved mainly at the terminals, and that each of these systems contributes to the regulation of the other two.