Neuroscience letters
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Neuroscience letters · Nov 2015
Protective effects of Ephedra sinica extract on blood-brain barrier integrity and neurological function correlate with complement C3 reduction after subarachnoid hemorrhage in rats.
Early brain injury, which is associated with brain cell death, blood-brain barrier disruption, brain edema, and other pathophysiological events, is thought to be the main target in the prevention of poor outcomes after subarachnoid hemorrhage (SAH). Emerging evidences indicates that complement system, especially complement C3 is detrimental to neurological outcomes of SAH patients. Recently, Ephedra sinica extract was extracted and purified, which exhibits ability to block the activity of the classical and alternative pathways of complement, and improve neurological outcomes after spinal cord injury and ischemic brain injury. ⋯ We founded that the Ephedra sinica extract alleviated the blood-brain barrier disruption and brain edema, eventually improved neurological functions after SAH in rats. These neuroprotective effects was associated with the inhibition of complement C3, possibly via upregulating sonic hedgehog and osteopontin signal, and reducing the expressions of matrix metalloproteinase-9. Taking together, these observations suggested complement C3 inhibition by the Ephedra sinica extract may be a protective factor against early brain injury after SAH.
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Neuroscience letters · Nov 2015
Blockade of high mobility group box-1 signaling via the receptor for advanced glycation end-products ameliorates inflammatory damage after acute intracerebral hemorrhage.
Intracerebral hemorrhage (ICH) is a devastating disease with no specific treatment. Increasing evidence indicates that inflammatory response plays a critical role in ICH-induced damage. High mobility group box-1 protein (HMGB1) may trigger inflammatory response via three putative receptors: receptor for advanced glycation end-products (RAGE), toll-like receptor-2 (TLR2) and toll-like receptor-4 (TLR4). ⋯ Treatment with EP or FPS-ZM1 also led to greater neurobehavioral function and less brain edema, hemorrhage volume and brain damage after ICH. In contrast, treatment with TLR2/4 antagonists did not significantly affect these post-ICH outcomes. Our results suggest that RAGE may play a specific role in the acute phase of ICH, so targeting the HMGB1-RAGE signaling pathway may be a promising therapeutic strategy.
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Neuroscience letters · Nov 2015
Effects of paired transcutaneous electrical stimulation delivered at single and dual sites over lumbosacral spinal cord.
It was demonstrated previously that transcutaneous electrical stimulation of multiple sites over the spinal cord is more effective in inducing robust locomotor behavior as compared to the stimulation of single sites alone in both animal and human models. To explore the effects and mechanisms of interactions during multi-site spinal cord stimulation we delivered transcutaneous electrical stimulation to the single or dual locations over the spinal cord corresponding to approximately L2 and S1 segments. Spinally evoked motor potentials in the leg muscles were investigated using single and paired pulses of 1ms duration with conditioning-test intervals (CTIs) of 5 and 50ms. ⋯ At CTI-50, the magnitude of inhibition did not differ among paired stimulation paradigms. Our results suggest that electrical stimuli delivered to dual sites over the lumbosacral enlargement in rostral-to-caudal order, may recruit different populations of motor neurons initially through projecting sensory and intraspinal connections and then directly, resulting in potentiation of the compound spinally evoked motor potentials. The interactive and synergistic effects indicate multi-segmental convergence of descending and ascending influences on the neuronal circuitries during electrical spinal cord stimulation.
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Neuroscience letters · Nov 2015
Down-regulation of astroglial glutamate transporter-1 in the locus coeruleus impairs pain-evoked endogenous analgesia in rats.
Descending noradrenergic inhibition to the spinal cord from the locus coeruleus (LC) is an important endogenous pain-relief mechanism which can be activated by local glutamate signaling. Here we tested whether dysregulation of extracellular glutamate level in the LC induced by down-regulating astroglial glutamate transporter-1(GLT-1) impairs endogenous analgesia. ⋯ LC-injected GLT-1 siRNA impaired capsaicin-evoked release of LC glutamate and spinal noradrenaline, capsaicin-evoked LC neuronal activation, and NSIA. These results suggest that astroglial GLT-1 is essential to normal LC function and that increased extracellular glutamate by down-regulating GLT-1 impairs evoked LC activity and NSIA, essentially taking the LC "off-line".
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Neuroscience letters · Nov 2015
Regulation of neuropathic pain behavior by amygdaloid TRPC4/C5 channels.
Pain per se may increase anxiety and conversely, anxiety may increase pain. Therefore, a positive feedback loop between anxiety and pain possibly contributes to pain and suffering in some pathophysiological pain conditions, such as that induced by peripheral nerve injury. Recent results indicate that transient receptor channels 4 and 5 (TRPC4/C5) in the amygdala have anxiogenic effects in rodents, while their role in chronic pain conditions is not known. ⋯ In the internal capsule, ML-204 had no effect on hypersensitivity or affective-like pain in SNI animals. In healthy controls, amygdaloid administration of ML-204 failed to influence pain behavior induced by mechanical stimulation or noxious heat. The results indicate that the amygdaloid TRPC4/C5 contribute to maintenance of pain hypersensitivity and pain affect in neuropathy.