Neuroscience letters
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Neuroscience letters · Aug 2014
Analgesic tolerance and cross-tolerance to the cannabinoid receptors ligands hemopressin, VD-hemopressin(α) and WIN55,212-2 at the supraspinal level in mice.
The nonapeptide hemopressin and its N-terminal extension VD-hemopressin(α) were reported as an antagonist/inverse agonist and an agonist of CB1 receptor, respectively. These novel cannabinoid peptides have been demonstrated to modulate the acute pain. In the present study, hemopressin (11, 22 and 45 nmol, i.c.v.) dose-dependently produced antinociception after supraspinal administration in the radiant heat tail-flick test. ⋯ Our results indicated symmetrical cross-tolerance between hemopressin, VD-hemopressin(α) and WIN55,212-2 at the supraspinal level in mice. These results demonstrate that both hemopressin and VD-hemopressin(α) have a time-course and extent of tolerance similar to the synthetic cannabinoid WIN55,212-2. In addition, our data imply that a common mechanism is involved in the antinociception of the three cannabinoid ligands.
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Neuroscience letters · Aug 2014
Randomized Controlled TrialQEEG indexed frontal connectivity effects of transcranial pulsed current stimulation (tPCS): A sham-controlled mechanistic trial.
Transcranial pulsed current stimulation (tPCS) is a non-invasive brain stimulation technique that employs weak, pulsed current at different frequency ranges, inducing electrical currents that reach cortical and subcortical structures. Very little is known about its effects on brain oscillations and functional connectivity and whether these effects are dependent on the frequency of stimulation. Our aim was to evaluate the effects of tPCS with different frequency ranges in cortical oscillations indexed by high-resolution qEEG changes for power and interhemispheric coherence. ⋯ We found that active stimulation with a random frequency ranging between 1 and 5 Hz is able to significantly increase functional connectivity for the theta and low-alpha band as compared to sham and active stimulation with either 1 or 100 Hz. Based on these findings, we discuss the possible effects of tPCS on resting functional connectivity for low-frequency bands in fronto-temporal areas. Future studies should be conducted to investigate the potential benefit of these induced changes in pathologic states.
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Neuroscience letters · Aug 2014
Neuroglobin overexpression improves sensorimotor outcomes in a mouse model of traumatic brain injury.
There is a significant need for novel treatments that will improve traumatic brain injury (TBI) outcomes. One potential neuroprotective mechanism is to increase oxygen binding proteins such as neuroglobin. Neuroglobin has a high affinity for oxygen, is an effective free radical scavenger, and is neuroprotective within the brain following hypoxia and ischemia. ⋯ Immunostaining showed neuroglobin primarily localized to neurons and glial cells in the injured cortex and ipsilateral hippocampus of WT mice, while neuroglobin was present in all brain regions of NGB mice at 7 days post-TBI. These results showed that overexpression of neuroglobin reduced sensorimotor deficits following TBI, and that an endogenous increase in neuroglobin expression occurs during the subacute period. Increasing neuroglobin expression through novel therapeutic interventions during the acute period after TBI may improve recovery.
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Neuroscience letters · Aug 2014
Microvascular network alterations in retina of subjects with cerebral small vessel disease.
Novel retinal imaging techniques have enabled the assessment of quantitative vascular parameters, which provide information on the microvasculature before the appearance of retinopathy signs. Advances in neuroimaging have revealed that cerebral microbleeds (CMB) - besides lacunar infarcts and white matter lesions (WML) - may be a novel marker of cerebral small vessel disease. We examine whether quantitative retinal vascular parameters are related to cerebral small vessel disease in a Chinese population. ⋯ In contrast, no association was found with lacunar infarcts and WML volume. After multivariate adjustments, associations of venular caliber, arteriolar fractal dimensions and arteriolar tortuosity with CMB remained statistically significant. In conclusion, subjects with early structural changes in retinal microvasculature were more likely to have CMBs, supporting hypothesis that CMB may be an early manifestation of cerebral small vessel disease.
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Neuroscience letters · Jun 2014
Genome-wide schizophrenia variant at MIR137 does not impact white matter microstructure in healthy participants.
A single nucleotide polymorphism (SNP rs1625579) within the micro-RNA 137 (MIR137) gene recently achieved strong genome-wide association with schizophrenia (SZ). However, the mechanisms by which SZ risk may be mediated by this variant are unknown. As miRNAs have the potential to influence oligodendrocyte development, we investigated whether this SNP was associated with variability in white matter (WM) microstructure. ⋯ No significant differences in either whole-brain fractional anisotropy or mean diffusivity between MIR137 genotype groups were observed (p>0.05). Similarly, atlas-based tractography of particular tracts implicated in SZ failed to reveal any significant differences between MIR137 genotype groups on measures of WM connectivity (p>0.05). In the absence of WM effects comparable to those reported for other SZ associated genes, these data suggest that MIR137 alone may not confer variability in these WM measures and therefore may not act in isolation for any effects that the variant may have on WM microstructure in SZ samples.