Neuroscience
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Identifying novel neuroprotectants that can halt or even reverse the effects of stroke is of interest to both clinicians and scientists. Neuregulin 1 (NRG1) is an effective neuroprotectant, but its molecular mechanisms are largely unclear. ⋯ Importantly, NRG1 neuroprotection against brain ischemia was abolished in the mice with specific deletion of ErbB4 in parvalbumin (PV)-positive interneurons. In summary, NRG1 protects against ischemic brain injury via ErbB4 receptors by enhancing GABAergic transmission.
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Spinal cord injury (SCI) that disrupts input from higher brain centers to the lumbar region of the spinal cord results in paraplegia, one of the most debilitating conditions affecting locomotion. Non-human primates have long been considered to be the most appropriate animal to model lower limb dysfunction. More recently, however, there has been a wealth of scientific information gathered in the rat regarding the central control of locomotion. ⋯ For each muscle under scrutiny, injections of Fluoro-Gold were then performed along the length of the MEP region. Targeting the MEPs gave rise to columns of motor neurons that span more spinal cord segments than previously reported. The importance of this study is discussed in terms of its application to gene therapy for SCI.
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Interleukin-6 (IL-6) has been shown to promote post-stroke angiogenesis and long-term functional recovery; however, whether IL-6 could promote post-stroke neurogenesis remains unclear. This study aims to investigate the effects of IL-6 on neurogenesis after ischemic stroke. We also investigated whether pair housing (PH) could improve the experimental stroke outcome through IL-6. ⋯ We found that anti-IL-6 mAbs significantly reduced the proliferation and neuronal differentiation of NPCs in the ipsilateral SVZ, as well as functional recovery; whereas rIL-6 conferred the opposite effects. PH significantly promoted NPC proliferation and functional recovery compared with socially isolated cohorts; blockade of IL-6 with anti-IL-6 mAbs prevented this promoting effect. In conclusion, our results suggest that IL-6 is an important mediator of social interaction on neurogenesis and long-term functional recovery after ischemic stroke.
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Sensory information from the orofacial mechanoreceptors are used by the nervous system to optimize the positioning of food, determine the force levels, and force vectors involved in biting of food morsels. Moreover, practice resulting from repetition could be a key to learning and acquiring a motor skill. Hence, the aim of the experiment was to test the hypothesis that repeated splitting of a food morsel during a short-term training with an oral fine motor task would result in increased performance and optimization of jaw movements, in terms of reduction in duration of various phases of the jaw movements. ⋯ Further, when the jaw movements were divided into different phases, the jaw opening phase and contact phase were significantly shorter after training than before training (P=0.001, P=0.002). The results indicate that short-term training of an oral fine motor task induces behavior learning, skill acquisition and optimization of jaw movements in terms of better performance and reduction in the duration of jaw movements, during the task. The finding of the present study provides insights into how humans learn oral motor behaviors or the kind of adaptation that takes place after a successful prosthetic rehabilitation.
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There is growing interest in the development of cannabis-based therapies for the treatment of fear and anxiety disorders. There are a few studies, but none in females, of the effects of the highly selective cannabinoid receptor type 1 (CB1) agonist, arachidonyl 2'-chlorethylamide (ACEA), on behavioral fear. In experiment 1 involving gonadally-intact females, ACEA (either 0.1 or 0.01 mg/kg) was without effect in the elevated plus maze (EPM), and the lower dose decreased anxiety in the open field test (OFT). ⋯ Neither hormone nor drug had any effect on recall or extinction of conditioned fear, however, ACEA and AM251 increased fear-induced plasma corticosterone concentrations. Further, when results with intact rats were compared with those from OVX rats, gonadal status did not moderate the effects of either AM251 or ACEA, although OVX displayed greater anxiety and fear than did intact rats. Thus, the effects of CB1 receptor antagonism and agonism in adult female rats do not depend on ovarian estradiol.