Neuroscience letters
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Neuroscience letters · May 2013
Association between the variable number of tandem repeat polymorphism in the third exon of the dopamine D4 receptor gene and sensitivity to analgesics and pain in patients undergoing painful cosmetic surgery.
To elucidate the mechanisms of individual differences in pain and analgesic sensitivity, we analyzed the variable number of tandem repeat polymorphism in the third exon of the dopamine D4 receptor gene. Alleles that were less than four repeats long and four or more repeats long were considered Short and Long, respectively. We found that the Short/Short genotype group was significantly more sensitive to pain and less sensitive to analgesics than the Short/Long+Long/Long genotype group. Our data suggest that this polymorphism may predict individual differences in pain and analgesic sensitivity and help achieve adequate pain control in the future.
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Neuroscience letters · May 2013
Spinal neuronal plasticity is evident within 1 day after a painful cervical facet joint injury.
Excessive stretch of the cervical facet capsular ligament induces persistent pain and spinal plasticity at later time points. Yet, it is not known when such spinal modifications are initiated following this painful injury. This study investigates the development of hyperalgesia and neuronal hyperexcitability in the spinal cord after a facet joint injury. ⋯ At 1 day, spontaneous firing was noted in a greater number of neurons after injury than sham (p<0.04). Evoked firing was also increased 1 day after injury compared to normal and sham (p<0.03). Dorsal horn hyperexcitability and increased spontaneous firing developed between 6 and 24h after painful facet injury, suggesting that the development of hyperalgesia parallels dorsal horn hyperexcitability following mechanical facet joint injury, and these spinal mechanisms are initiated as early as 1 day after injury.
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Neuroscience letters · May 2013
Excitotoxic spinal cord injury induced dysesthesias are associated with enhanced intrinsic growth of sensory neurons.
Sensory dysesthesias and pain are common sequelae following spinal cord injury (SCI). While efforts to understand the mechanisms involved in SCI pain syndromes have focused on spinal and supraspinal regions, recent evidence suggests that SCI induces pathological responses in primary afferent neurons that may contribute to the development of sensory abnormalities. The purpose of this study was to investigate if excitotoxic spinal lesions lead to abnormal growth responses of cultured dorsal root ganglia (DRG) neurons, and to examine if the degree of neurite growth correlated with the presence of dysesthesias. ⋯ Grooming animals showed robust neurite growth in small, medium, and large neurons compared to nongrooming and control animals. Enhanced neuronal growth responses also occurred several segments caudal to the level of injury. This study provides the first evidence that excitotoxic spinal lesions result in DRG neurite outgrowth that correlated with the presence of sensory dysesthesias, providing support for the role of maladaptive peripheral afferent responses contributing to SCI pain syndromes.
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Neuroscience letters · May 2013
Butein inhibits NF-κB activation and reduces infiltration of inflammatory cells and apoptosis after spinal cord injury in rats.
The IKK/NF-κB signalling pathway plays a predominant role in the regulation of inflammation and apoptosis in spinal cord injury (SCI). We have previously demonstrated that targeting of the IKK/NF-κB pathway improved the recovery of locomotor function by reducing the infiltration of inflammatory cells and apoptosis after SCI in rats. Recently, the neuroprotective effects of butein have been shown via direct inhibition of the IKK/NF-κB pathway in vitro. ⋯ Treatment with butein also resulted in significant inhibition of caspase-3 activation and neutrophil infiltration. Overall, our findings demonstrated the neuroprotective effects of butein in SCI in vivo and its potential mechanism. Our results further indicated that targeting of the IKK/NF-κB pathway may be useful in SCI therapy.