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Effects of Parecoxib and Fentanyl on nociception-induced cortical activity.

Peng YZ, Li XX, Wang YW - Mol Pain (2010)

Bottom Line: The effects of parecoxib and fentanyl on induced cortical activity were compared.Parecoxib, on the other hand, did not significantly affect the neural activity.Fentanyl showed a strong inhibitory effect on the nociceptive-stimulus induced cortical activity while parecoxib had no significant effect.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.

ABSTRACT

Background: Analgesics, including opioids and non-steroid anti-inflammatory drugs reduce postoperative pain. However, little is known about the quantitative effects of these drugs on cortical activity induced by nociceptive stimulation. The aim of the present study was to determine the neural activity in response to a nociceptive stimulus and to investigate the effects of fentanyl (an opioid agonist) and parecoxib (a selective cyclooxygenase-2 inhibitor) on this nociception-induced cortical activity evoked by tail pinch. Extracellular recordings (electroencephalogram and multi-unit signals) were performed in the area of the anterior cingulate cortex while intracellular recordings were made in the primary somatosensory cortex. The effects of parecoxib and fentanyl on induced cortical activity were compared.

Results: Peripheral nociceptive stimulation in anesthetized rats produced an immediate electroencephalogram (EEG) desynchronization resembling the cortical arousal (low-amplitude, fast-wave activity), while the membrane potential switched into a persistent depolarization state. The induced cortical activity was abolished by fentanyl, and the fentanyl's effect was reversed by the opioid receptor antagonist, naloxone. Parecoxib, on the other hand, did not significantly affect the neural activity.

Conclusion: Cortical activity was modulated by nociceptive stimulation in anesthetized rats. Fentanyl showed a strong inhibitory effect on the nociceptive-stimulus induced cortical activity while parecoxib had no significant effect.

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Electrophysiological recordings from cortical areas during nociceptive stimulation. A, upper panel: Trace of the extracellular signal from the ACC, showing that the amplitude was reduced while the frequency was increased when a nociceptive stimulus was applied; lower panel: Intracellular trace from S1, showing that the Down state disappeared and the membrane potential (Vm) switched to a persistent Up state during nociceptive stimulation. B: The Multi-Unit signal was filtered from the upper panel in A. The spike firing rate of the MU signal was increased, and the Down state disappeared under nociceptive stimulation. C, upper panel: the trace filtered from A (upper panel), note that EEG waves switched to low-amplitude, high-frequency pattern activity; lower panel: The power spectrum of the corresponding EEG (C, upper panel), showing that the low frequency band was markedly reduced. D: The traces recorded from the ACC (upper panel) and from V1 (lower panel). E: The traces recorded from PtA (upper panel) and FrA (lower panel). Triangles signify the start and end of nociceptive stimulation. The color bar represents the proportion of EEG bands.
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Figure 1: Electrophysiological recordings from cortical areas during nociceptive stimulation. A, upper panel: Trace of the extracellular signal from the ACC, showing that the amplitude was reduced while the frequency was increased when a nociceptive stimulus was applied; lower panel: Intracellular trace from S1, showing that the Down state disappeared and the membrane potential (Vm) switched to a persistent Up state during nociceptive stimulation. B: The Multi-Unit signal was filtered from the upper panel in A. The spike firing rate of the MU signal was increased, and the Down state disappeared under nociceptive stimulation. C, upper panel: the trace filtered from A (upper panel), note that EEG waves switched to low-amplitude, high-frequency pattern activity; lower panel: The power spectrum of the corresponding EEG (C, upper panel), showing that the low frequency band was markedly reduced. D: The traces recorded from the ACC (upper panel) and from V1 (lower panel). E: The traces recorded from PtA (upper panel) and FrA (lower panel). Triangles signify the start and end of nociceptive stimulation. The color bar represents the proportion of EEG bands.

Mentions: We simultaneously measured extracellular activity in the ACC and intracellular activity in the S1 region in response to nociceptive stimulation. We found that both the ACC and S1 areas were activated by tail pinch in urethane anesthetized rats (Fig. 1A). To examine whether the neural activity of other cortical areas could be altered by nociceptive stimulation, we performed recordings at V1(primary visual cortex), PtA(parietal association cortex) and FrA(frontal association cortex), which presented similar activity to that seen in ACC and S1 (Fig. 1D and 1E).


Effects of Parecoxib and Fentanyl on nociception-induced cortical activity.

Peng YZ, Li XX, Wang YW - Mol Pain (2010)

Electrophysiological recordings from cortical areas during nociceptive stimulation. A, upper panel: Trace of the extracellular signal from the ACC, showing that the amplitude was reduced while the frequency was increased when a nociceptive stimulus was applied; lower panel: Intracellular trace from S1, showing that the Down state disappeared and the membrane potential (Vm) switched to a persistent Up state during nociceptive stimulation. B: The Multi-Unit signal was filtered from the upper panel in A. The spike firing rate of the MU signal was increased, and the Down state disappeared under nociceptive stimulation. C, upper panel: the trace filtered from A (upper panel), note that EEG waves switched to low-amplitude, high-frequency pattern activity; lower panel: The power spectrum of the corresponding EEG (C, upper panel), showing that the low frequency band was markedly reduced. D: The traces recorded from the ACC (upper panel) and from V1 (lower panel). E: The traces recorded from PtA (upper panel) and FrA (lower panel). Triangles signify the start and end of nociceptive stimulation. The color bar represents the proportion of EEG bands.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2819047&req=5

Figure 1: Electrophysiological recordings from cortical areas during nociceptive stimulation. A, upper panel: Trace of the extracellular signal from the ACC, showing that the amplitude was reduced while the frequency was increased when a nociceptive stimulus was applied; lower panel: Intracellular trace from S1, showing that the Down state disappeared and the membrane potential (Vm) switched to a persistent Up state during nociceptive stimulation. B: The Multi-Unit signal was filtered from the upper panel in A. The spike firing rate of the MU signal was increased, and the Down state disappeared under nociceptive stimulation. C, upper panel: the trace filtered from A (upper panel), note that EEG waves switched to low-amplitude, high-frequency pattern activity; lower panel: The power spectrum of the corresponding EEG (C, upper panel), showing that the low frequency band was markedly reduced. D: The traces recorded from the ACC (upper panel) and from V1 (lower panel). E: The traces recorded from PtA (upper panel) and FrA (lower panel). Triangles signify the start and end of nociceptive stimulation. The color bar represents the proportion of EEG bands.
Mentions: We simultaneously measured extracellular activity in the ACC and intracellular activity in the S1 region in response to nociceptive stimulation. We found that both the ACC and S1 areas were activated by tail pinch in urethane anesthetized rats (Fig. 1A). To examine whether the neural activity of other cortical areas could be altered by nociceptive stimulation, we performed recordings at V1(primary visual cortex), PtA(parietal association cortex) and FrA(frontal association cortex), which presented similar activity to that seen in ACC and S1 (Fig. 1D and 1E).

Bottom Line: The effects of parecoxib and fentanyl on induced cortical activity were compared.Parecoxib, on the other hand, did not significantly affect the neural activity.Fentanyl showed a strong inhibitory effect on the nociceptive-stimulus induced cortical activity while parecoxib had no significant effect.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anesthesiology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200092, China.

ABSTRACT

Background: Analgesics, including opioids and non-steroid anti-inflammatory drugs reduce postoperative pain. However, little is known about the quantitative effects of these drugs on cortical activity induced by nociceptive stimulation. The aim of the present study was to determine the neural activity in response to a nociceptive stimulus and to investigate the effects of fentanyl (an opioid agonist) and parecoxib (a selective cyclooxygenase-2 inhibitor) on this nociception-induced cortical activity evoked by tail pinch. Extracellular recordings (electroencephalogram and multi-unit signals) were performed in the area of the anterior cingulate cortex while intracellular recordings were made in the primary somatosensory cortex. The effects of parecoxib and fentanyl on induced cortical activity were compared.

Results: Peripheral nociceptive stimulation in anesthetized rats produced an immediate electroencephalogram (EEG) desynchronization resembling the cortical arousal (low-amplitude, fast-wave activity), while the membrane potential switched into a persistent depolarization state. The induced cortical activity was abolished by fentanyl, and the fentanyl's effect was reversed by the opioid receptor antagonist, naloxone. Parecoxib, on the other hand, did not significantly affect the neural activity.

Conclusion: Cortical activity was modulated by nociceptive stimulation in anesthetized rats. Fentanyl showed a strong inhibitory effect on the nociceptive-stimulus induced cortical activity while parecoxib had no significant effect.

Show MeSH
Related in: MedlinePlus