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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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Related in: MedlinePlus

Group data for intracellular recordings at S1. The time ratio of Down state to Up state decreased (A, control), while transition frequency of Up state and the distance of cumulative Vmdistribution increased (B and C, control) in response to nociceptive stimulation. The response of all measures to nociceptive stimulation was not inhibited by parecoxib (left panels, n = 8). Fentanyl (right panels, n = 12) inhibited all responses and naloxone reversed fentanyl's action (n = 9). *P < 0.05, **P < 0.01, #P < 0.001.
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Figure 6: Group data for intracellular recordings at S1. The time ratio of Down state to Up state decreased (A, control), while transition frequency of Up state and the distance of cumulative Vmdistribution increased (B and C, control) in response to nociceptive stimulation. The response of all measures to nociceptive stimulation was not inhibited by parecoxib (left panels, n = 8). Fentanyl (right panels, n = 12) inhibited all responses and naloxone reversed fentanyl's action (n = 9). *P < 0.05, **P < 0.01, #P < 0.001.

Mentions: Finally, we investigated the Up and Down states under different conditions in the S1 region. The ratio of time in the Down state to time in the Up state was reduced and the firing rate of the Up state increased (Fig. 6A, B; control) during nociceptive stimulation. Administration of fentanyl reversed these responses while the addition of naloxone abolished the fentanyl's effects (Fig. 6A and 6B, right panels). In addition, the distance of membrane potential distribution was significantly increased during tail pinch (Fig. 6C; control) and administration of fentanyl significantly inhibited this response. Naloxone was again able to reverse the fentanyl effect (Fig. 6C, right panel). Parecoxib had no significant effect on any of these measures (Fig. 6, left panels).


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

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

Group data for intracellular recordings at S1. The time ratio of Down state to Up state decreased (A, control), while transition frequency of Up state and the distance of cumulative Vmdistribution increased (B and C, control) in response to nociceptive stimulation. The response of all measures to nociceptive stimulation was not inhibited by parecoxib (left panels, n = 8). Fentanyl (right panels, n = 12) inhibited all responses and naloxone reversed fentanyl's action (n = 9). *P < 0.05, **P < 0.01, #P < 0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 6: Group data for intracellular recordings at S1. The time ratio of Down state to Up state decreased (A, control), while transition frequency of Up state and the distance of cumulative Vmdistribution increased (B and C, control) in response to nociceptive stimulation. The response of all measures to nociceptive stimulation was not inhibited by parecoxib (left panels, n = 8). Fentanyl (right panels, n = 12) inhibited all responses and naloxone reversed fentanyl's action (n = 9). *P < 0.05, **P < 0.01, #P < 0.001.
Mentions: Finally, we investigated the Up and Down states under different conditions in the S1 region. The ratio of time in the Down state to time in the Up state was reduced and the firing rate of the Up state increased (Fig. 6A, B; control) during nociceptive stimulation. Administration of fentanyl reversed these responses while the addition of naloxone abolished the fentanyl's effects (Fig. 6A and 6B, right panels). In addition, the distance of membrane potential distribution was significantly increased during tail pinch (Fig. 6C; control) and administration of fentanyl significantly inhibited this response. Naloxone was again able to reverse the fentanyl effect (Fig. 6C, right panel). Parecoxib had no significant effect on any of these measures (Fig. 6, left panels).

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