Neuroreport
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It is unknown whether normobaric oxygen (NBO) therapy exerts neuroprotective effects against human intracerebral hemorrhage (ICH). In this study, the potential of NBO therapy for salvaging brain damage following ICH was investigated in a rodent model with oxygen delivered at different concentrations. A total of 164 male Sprague-Dawley rats were induced with ICH using a collagenase injection and divided randomly into one ICH control group (no treatment, n=86) and three NBO treatment groups (35, 50, or 90% oxygen, n=26/group). ⋯ ICH rats also showed higher contents of brain water, HIF-1α, and VEGF (peaked at 72 h) in the ipsilateral perihematoma tissue than in the contralateral brain tissue. Compared with the ICH control group, all NBO groups showed improved NSSs, decreased contents of brain water, HIF-1α and VEGF, and fewer apoptotic cells in the perihematoma at 72 h after ICH, but statistical significance of these changes was achieved only with oxygen delivered at 90% (P<0.05, two-way analysis of variance). These results suggest that NBO therapy with oxygen delivered at 90% conferred best neuroprotection to ICH rats, potentially through amelioration of brain edema by suppressing HIF-1α and VEGF expression in the perihematoma.
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Event-related potentials (ERPs) were recorded to explore, for the first time, the electrophysiological correlates of the shape Stroop effect. Fifteen healthy individuals were presented with a frame and a name of an object with a typical shape in life and asked to categorize the object's typical shape in life as a 'circle', a 'square,' or a 'triangle' by pressing the relevant button as quickly as possible. ⋯ N430 is a critical sign of conflict detection in the early stage, whereas late positive component reflects the response conflict in the late stage. The results provided evidence for the dissociation between conflict detection and conflict resolution in the shape Stroop effect.
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P2X3 receptor plays a role in nociception transmission of orofacial pain in temporomandibular disorder patients. A previous study found that P2X3 receptors in masseter muscle afferent neurons and the trigeminal ganglia were involved in masseter muscle pain induced by inflammation caused by chemical agents or eccentric muscle contraction. In this study, we attempted to investigate changes in P2X3 receptors in the trigeminal subnucleus caudalis (Vc) and midbrain periaqueductal gray (PAG) in relation to the hyperalgesia of masseter muscles induced by occlusal interference. ⋯ We found that mechanical pain threshold of bilateral masseter muscles decreased significantly after occlusal interference, which remained for the entire experimental period. The mRNA expression of the P2X3 receptor increased significantly and the number of P2X3R-positive neurons increased markedly in Vc and PAG accordingly. These results indicate that the upregulated expression of P2X3 receptors in Vc and PAG may contribute toward the development of orofacial pain induced by occlusal interference and P2X3 receptors in the PAG may play a key role in the supraspinal antiociception effect.
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This study aimed to investigate the dysfunctional ascending/descending pain pathways at the thalamic level in patients with migraine without aura (MWoA) using the effective connectivity analysis of the resting-state functional MRI. Twenty MWoA and 25 matched healthy controls participated in the resting-state functional MRI scans. The directional interactions between the posterior thalamus (PTH) and other brain regions were investigated using the Granger causality analysis and choosing bilateral PTH as two individual seeds. ⋯ In addition, the abnormal inflows to the right PTH from the ventromedial prefrontal cortex and the right dorsolateral prefrontal cortex correlated positively with the headache duration and pain intensity, respectively. The abnormal ascending/descending pain pathways between the thalamus and these cortical regions indicate a disrupted pain modulation in affective and sensory domains, which suggests a disequilibrium of pain inhibition and facilitation in MWoA. These findings may help to shed light on the pathophysiologic mechanisms of migraine.