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A [14C]iodoantipyrine study of inter-regional correlations of neural substrates following central post-stroke pain in rats.

Lu HC, Chang WJ, Kuan YH, Huang AC, Shyu BC - Mol Pain (2015)

Bottom Line: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms.The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP.The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan. nhnsc@hotmail.com.

ABSTRACT

Background: Central pain syndrome is characterized by a combination of abnormal pain sensations, and pain medications often provide little or no relief. Accumulating animal and clinical studies have shown that impairments of the spinothalamic tract (STT) and thalamocingulate pathway causes somatosensory dysfunction in central post-stroke pain (CPSP), but the involvement of other neuronal circuitries in CPSP has not yet been systematically examined. The aim of the present study was to evaluate changes in brain activity and neuronal circuitry using [(14)C]iodoantipyrine (IAP) in an animal model of CPSP.

Results: Rats were subjected to lateral thalamic hemorrhage to investigate the characteristics of CPSP. Thermal and mechanical hyperalgesia developed in rats that were subjected to thalamic hemorrhagic lesion. The medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), striatum, thalamus, hypothalamus, and amygdala were more active in the CPSP group compared with rats that were not subjected to lateral thalamic hemorrhage. The inter-regional correlation analysis showed that regional cerebral blood flow in the mPFC was highly correlated with the amygdala in the right brain, and the right brain showed complex connections among subregions of the ACC. Rats with CPSP exhibited strong activation of the thalamocingulate and mPFC-amygdala pathways.

Conclusions: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms. The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP. The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

No MeSH data available.


Related in: MedlinePlus

Region-of-interest (ROI) analysis. A. The boundaries of the ROIs were chosen based on available anatomic atlases. B. In the comparison of the relative ratios of the left hemisphere ROIs in the different groups, the radioactivity ratios of the IL, GI-3, AID, AIV, Hippo-3, and PAG in the CPSP group were significantly higher than in the sham group, and the Cg1-2 and M2-2 in the CPSP group were significantly lower than in the sham group. C. In the comparison of the relative ratios of the right hemisphere ROIs in the different groups, the radioactivity ratios of the IL, PrL, Cg1-1, and Amy-2 in the CPSP group were significantly higher than in the sham group, and the M2-2 and VB were significantly lower. p < 0.05 (three-way ANOVA followed by post hoc test).
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Fig4: Region-of-interest (ROI) analysis. A. The boundaries of the ROIs were chosen based on available anatomic atlases. B. In the comparison of the relative ratios of the left hemisphere ROIs in the different groups, the radioactivity ratios of the IL, GI-3, AID, AIV, Hippo-3, and PAG in the CPSP group were significantly higher than in the sham group, and the Cg1-2 and M2-2 in the CPSP group were significantly lower than in the sham group. C. In the comparison of the relative ratios of the right hemisphere ROIs in the different groups, the radioactivity ratios of the IL, PrL, Cg1-1, and Amy-2 in the CPSP group were significantly higher than in the sham group, and the M2-2 and VB were significantly lower. p < 0.05 (three-way ANOVA followed by post hoc test).

Mentions: To further evaluate changes in brain areas associated with CPSP symptoms, a region-of-interest (ROI) analysis was conducted. Different brain areas related to CPSP were distinguished and quantitatively analyzed. The ROI analysis was conducted based on the results of the functional brain images of [14C]-IAP uptake shown in Figure 3. The assignment of the ROIs for specific brain areas is shown in Figure 4A. A 2 × 31 × 2 three-way (group vs. brain area vs. hemisphere) ANOVA was used for the analysis, which revealed significant main effects of group (F1,744 = 29.55, p < 0.05), brain area (F30,744 = 119.12, p < 0.05), and hemisphere (F1,744 = 18.05, p < 0.05), a group × brain area interaction (F30,744 = 17.44, p < 0.05), a brain area × hemisphere interaction (F30,744 = 4.94, p < 0.05), and a group × brain area × hemisphere interaction (F30,744 = 1.88, p < 0.05). No group × hemisphere interaction was found (F1,744 = 0.30, p > 0.05).Figure 4


A [14C]iodoantipyrine study of inter-regional correlations of neural substrates following central post-stroke pain in rats.

Lu HC, Chang WJ, Kuan YH, Huang AC, Shyu BC - Mol Pain (2015)

Region-of-interest (ROI) analysis. A. The boundaries of the ROIs were chosen based on available anatomic atlases. B. In the comparison of the relative ratios of the left hemisphere ROIs in the different groups, the radioactivity ratios of the IL, GI-3, AID, AIV, Hippo-3, and PAG in the CPSP group were significantly higher than in the sham group, and the Cg1-2 and M2-2 in the CPSP group were significantly lower than in the sham group. C. In the comparison of the relative ratios of the right hemisphere ROIs in the different groups, the radioactivity ratios of the IL, PrL, Cg1-1, and Amy-2 in the CPSP group were significantly higher than in the sham group, and the M2-2 and VB were significantly lower. p < 0.05 (three-way ANOVA followed by post hoc test).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4358859&req=5

Fig4: Region-of-interest (ROI) analysis. A. The boundaries of the ROIs were chosen based on available anatomic atlases. B. In the comparison of the relative ratios of the left hemisphere ROIs in the different groups, the radioactivity ratios of the IL, GI-3, AID, AIV, Hippo-3, and PAG in the CPSP group were significantly higher than in the sham group, and the Cg1-2 and M2-2 in the CPSP group were significantly lower than in the sham group. C. In the comparison of the relative ratios of the right hemisphere ROIs in the different groups, the radioactivity ratios of the IL, PrL, Cg1-1, and Amy-2 in the CPSP group were significantly higher than in the sham group, and the M2-2 and VB were significantly lower. p < 0.05 (three-way ANOVA followed by post hoc test).
Mentions: To further evaluate changes in brain areas associated with CPSP symptoms, a region-of-interest (ROI) analysis was conducted. Different brain areas related to CPSP were distinguished and quantitatively analyzed. The ROI analysis was conducted based on the results of the functional brain images of [14C]-IAP uptake shown in Figure 3. The assignment of the ROIs for specific brain areas is shown in Figure 4A. A 2 × 31 × 2 three-way (group vs. brain area vs. hemisphere) ANOVA was used for the analysis, which revealed significant main effects of group (F1,744 = 29.55, p < 0.05), brain area (F30,744 = 119.12, p < 0.05), and hemisphere (F1,744 = 18.05, p < 0.05), a group × brain area interaction (F30,744 = 17.44, p < 0.05), a brain area × hemisphere interaction (F30,744 = 4.94, p < 0.05), and a group × brain area × hemisphere interaction (F30,744 = 1.88, p < 0.05). No group × hemisphere interaction was found (F1,744 = 0.30, p > 0.05).Figure 4

Bottom Line: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms.The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP.The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biomedical Sciences, Academia Sinica, Taipei, 11529, Taiwan. nhnsc@hotmail.com.

ABSTRACT

Background: Central pain syndrome is characterized by a combination of abnormal pain sensations, and pain medications often provide little or no relief. Accumulating animal and clinical studies have shown that impairments of the spinothalamic tract (STT) and thalamocingulate pathway causes somatosensory dysfunction in central post-stroke pain (CPSP), but the involvement of other neuronal circuitries in CPSP has not yet been systematically examined. The aim of the present study was to evaluate changes in brain activity and neuronal circuitry using [(14)C]iodoantipyrine (IAP) in an animal model of CPSP.

Results: Rats were subjected to lateral thalamic hemorrhage to investigate the characteristics of CPSP. Thermal and mechanical hyperalgesia developed in rats that were subjected to thalamic hemorrhagic lesion. The medial prefrontal cortex (mPFC), anterior cingulate cortex (ACC), striatum, thalamus, hypothalamus, and amygdala were more active in the CPSP group compared with rats that were not subjected to lateral thalamic hemorrhage. The inter-regional correlation analysis showed that regional cerebral blood flow in the mPFC was highly correlated with the amygdala in the right brain, and the right brain showed complex connections among subregions of the ACC. Rats with CPSP exhibited strong activation of the thalamocingulate and mPFC-amygdala pathways.

Conclusions: These results corroborate previous findings that the STT and thalamocingulate pathway are involved in the pathophysiological mechanisms of CPSP symptoms. The mPFC, amygdala, and periaqueductal gray emerged as having important correlations in pain processing in CPSP. The present data provide a basis for a neural correlation hypothesis of CPSP, with implications for CPSP treatment.

No MeSH data available.


Related in: MedlinePlus