Neuroscience letters
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Neuroscience letters · Aug 2013
Randomized Controlled TrialThe dopamine agonist apomorphine enhances conditioned pain modulation in healthy humans.
Although cumulative evidence suggests that dopamine plays a role in pain processing, the mechanisms by which dopaminergic transmission affects pain remain elusive. Conditioned pain modulation (CPM) is a psychophysical paradigm based on endogenous descending inhibitory pain modulation. The current study was aimed to test the effects of apomorphine, a non-specific dopamine agonist, on the magnitude of CPM in healthy subjects. ⋯ RM-ANOVA revealed a significant interaction between 'session' and 'time' factors (F=5.316, p=0.023, η=0.054), and significant effect for the 'session' (F=5.719, p=0.019, η=0.006), but not for the 'time' (F=0.586, p=0.446, η=0.057). These results suggest that dopaminergic pathways both participate in and enhance pain modulation, represented by CPM. The role of dopamine in pain processing should be further studied.
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Neuroscience letters · Aug 2013
Facilitation of corticospinal tract excitability by transcranial direct current stimulation combined with voluntary grip exercise.
Previous studies have established that transcranial direct current stimulation (tDCS) is a powerful technique for the deliberate manipulation of the activity of human cerebral cortex. Moreover, it has also been shown that the non-exhausted voluntary motor exercise increases the excitability of corticospinal tract. ⋯ Our result showed that the combination of anodal tDCS with voluntary grip exercise produced a 2-fold increase in the amplitude of MEP as compared with single use of anodal tDCS or voluntary grip exercise. In conclusion, our result could indicate that the treatment outcomes of brain and neurorehabilitation using tDCS would be better when tDCS is combined with the appropriate method of voluntary exercise as compared with single use of tDCS.
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Neuroscience letters · Aug 2013
Cortical activation during auditory elicitation of fear and disgust: a near-infrared spectroscopy (NIRS) study.
This near infrared spectroscopy study investigated whether nonverbal human sounds representing different basic emotions are able to specifically modulate temporo-parietal cortices, involved in auditory processing and attention. Forty-three adults (19 females and 24 males) were presented with sounds from the categories fear, disgust, and neutral. ⋯ The hemodynamic responses to disgusting sounds (e.g., sniffing, diarrhea) were smaller. Our findings point to a differential neuronal sensitivity of the human brain to two basic emotion elicitors in the auditory domain.
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Neuroscience letters · Aug 2013
Association of MTHFR C677T polymorphism with susceptibility to migraine in the Chinese population.
A number of genes have been implicated in the pathogenesis of migraine, a common neurological disorder also in China. However, data on association of genetic variations with migraine susceptibility among Chinese, which might be different from people of other ethnic background, are still scarce. We have therefore investigated the association of polymorphisms in four genes, MTHFR C677T, ACE I/D, MAOA T941G and TNF-β G252A, which are considered to be with risk of migraine. ⋯ No difference was found between migraine with aura (MA) patients and controls, but T allele frequency was significantly higher in migraine without aura (MO) than in controls (OR=1.744, 95% CI: 1.202-2.532, P=0.003). No difference in genotypic and allelic distributions was observed between migraine patients and controls for the other polymorphisms, including ACE I/D, MAOA T941G, and TNF-β G252A. Our data suggested that MTHFR C677T polymorphism plays a role in Chinese migraine susceptibility, especially in MO.
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Neuroscience letters · Aug 2013
Opposing effects of dexamethasone, agrin and sugammadex on functional innervation and constitutive secretion of IL-6 in in vitro innervated primary human muscle cells.
Neuromuscular junction development is the key process required for successful neuromuscular transmission and functional innervation of skeletal muscle fibres. Various substances can influence these processes, some of which are in common use in clinical practice. In the present study, the effects of the potentially new therapeutic agent agrin were followed, along with the widely used glucocorticoid dexamethasone. ⋯ Dexamethasone impaired functional innervation while agrin had opposing effects. Furthermore, based on interference with IL-6 secretion, we show potential (chemical) interactions between dexamethasone and sugammadex. The physiological effects of this interaction should be taken into consideration under clinical conditions where these two drugs might be applied simultaneously.