Brain research
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Our lab has previously elucidated the neuroprotective effects of normobaric oxygen (NBO) and ethanol (EtOH) in ischemic stroke. The present study further evaluated the effect of EtOH or hypothermia (Hypo) in the presence of low concentration of NBO and determined whether EtOH can substitute hypothermia in a more clinically relevant autologous embolus rat stroke model in which reperfusion was established by tissue-type plasminogen activator (t-PA). ⋯ Neuroprotection after stroke can be enhanced by combination treatment with either EtOH or hypothermia in the presence of t-PA and 60% NBO. Because the effects produced by EtOH and hypothermia are comparable, their mechanism of action may be not only similar but also could be interchangeable in future clinical trials.
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This study investigated the effect of repeated tongue lift training (TLT) on the excitability of the corticomotor representation of the human tongue and jaw musculature. Sixteen participants performed three series of TLT for 41 min on each of 5 consecutive days. Each TLT series consisted of two pressure levels (5 kPa and 10 kPa). ⋯ The amplitudes and thresholds of tongue and masseter MEPs after TLT on Day 5 were respectively higher and lower than before TLT on Day 1 (P<0.005), and there was also a significant increase in tongue and masseter MEP areas; no significant changes occurred in MEP onset latencies. FDI MEP parameters (amplitude, threshold, area, latency) were not significantly different between the four sessions. Our findings suggest that repeated TLT can trigger neuroplasticity reflected in increased excitability of the corticomotor representation of not only the tongue muscles but also the masseter muscles.
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A number of previous studies have suggested segregated networks of brain areas for top-down controlled and bottom-up triggered orienting of visual attention. However, the corresponding networks involved in auditory attention remain less studied. Our participants attended selectively to a tone stream with either a lower pitch or higher pitch in order to respond to infrequent changes in duration of attended tones. ⋯ Comparison of the present results with our previous results from a similar experiment on spatial auditory attention suggests that fronto-parietal networks of attention to location or pitch overlap substantially. However, the auditory areas in the anterior superior temporal cortex might have a more important role in attention to the pitch than location of sounds. This article is part of a Special Issue entitled SI: Prediction and Attention.
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The α7 nicotinic acetylcholine (nACh) receptor expressed in microglia has a crucial role in neuroprotection. Simulation of α7 nACh receptor leads to increased expression of glutamate/aspartate transporter (GLAST), which in turn decreases synaptic glutamate levels. However, the upregulation of GLAST in cultured rat cortical microglia appears long after (over 18 h) stimulation of the α7 nACh receptor with nicotine. ⋯ Conversely, pretreatment with PD173074, an inhibitor of FGF receptor (FGFR) tyrosine kinase, significantly prevented the nicotine-induced expression of GLAST mRNA, its protein and (14)C-glutamate uptake. Reverse transcription polymerase chain reaction confirmed FGFR1 mRNA expression was confined to cultured cortical microglia. Together, the current findings demonstrate that the neuroprotective effect of activation of microglial α7 nACh receptors could be due to the expression of FGF-2, which in turn increases GLAST expression, thereby clearing glutamate from synapse and decreasing glutamate neurotransmission.
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The trigeminovascular system has a pivotal role in the pathomechanism of migraine. The aim of the present study was to further develop existing models of migraine making them more suitable for testing the effects of compounds with presumed antimigraine activity in anaesthetised rats. Simultaneous recording of ongoing activity of spontaneously active neurons in the trigeminocervical complex as well as their discharges evoked by electrical stimulation of the dura mater via activation of A- and C-sensory fibres were carried out. ⋯ Nevertheless, inhibitory effect of propranolol and topiramate was evident when considering A- or C-fibre responses. Findings do not support the view that electrically evoked responses are useful for the measurement of trigeminal sensitization. It is proposed however, that inhibition of enhanced firing (immediate and/or delayed) evoked by inflammatory mediators as an endpoint have higher predictive validity regarding the clinical effectiveness of compounds.