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Nociceptive transmission to rat primary somatosensory cortex - comparison of sedative and analgesic effects.

Granmo, Marcus LU ; Jensen, Tanja LU and Schouenborg, Jens LU (2013) In PLoS ONE 8(1).
Abstract
CO(2)-laser C-fibre evoked cortical potentials (LCEPs) is a potentially useful animal model for studies of pain mechanisms. A potential confounding factor when assessing analgesic effects of systemically administered drugs using LCEP is sedation. This study aims to clarify: 1) the relation between level of anaesthesia and magnitude of LCEP, 2) the effects of a sedative and an analgesic on LCEP and dominant EEG frequency 3) the effects of a sedative and analgesic on LCEP when dominant EEG frequency is kept stable. LCEP and EEG were recorded in isoflurane/nitrous-oxide anaesthetized rats. Increasing isoflurane level gradually reduced LCEPs and lowered dominant EEG frequencies. Systemic midazolam (10 μmol/kg) profoundly reduced LCEP (19% of... (More)
CO(2)-laser C-fibre evoked cortical potentials (LCEPs) is a potentially useful animal model for studies of pain mechanisms. A potential confounding factor when assessing analgesic effects of systemically administered drugs using LCEP is sedation. This study aims to clarify: 1) the relation between level of anaesthesia and magnitude of LCEP, 2) the effects of a sedative and an analgesic on LCEP and dominant EEG frequency 3) the effects of a sedative and analgesic on LCEP when dominant EEG frequency is kept stable. LCEP and EEG were recorded in isoflurane/nitrous-oxide anaesthetized rats. Increasing isoflurane level gradually reduced LCEPs and lowered dominant EEG frequencies. Systemic midazolam (10 μmol/kg) profoundly reduced LCEP (19% of control) and lowered dominant EEG frequency. Similarly, morphine 1 and 3 mg/kg reduced LCEP (39%, 12% of control, respectively) and decreased EEG frequency. When keeping the dominant EEG frequency stable, midazolam caused no significant change of LCEP. Under these premises, morphine at 3 mg/kg, but not 1 mg/kg, caused a significant LCEP reduction (26% of control). In conclusion, the present data indicate that the sedative effects should be accounted for when assessing the analgesic effects of drug. Furthermore, it is suggested that LCEP, given that changes in EEG induced by sedation are compensated for, can provide information about the analgesic properties of systemically administrated drugs. (Less)
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author
organization
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Contribution to journal
publication status
published
subject
in
PLoS ONE
volume
8
issue
1
publisher
Public Library of Science
external identifiers
  • wos:000313429800074
  • pmid:23320109
  • scopus:84872173131
ISSN
1932-6203
DOI
10.1371/journal.pone.0053966
language
English
LU publication?
yes
id
2265c551-976d-4362-926c-8abb7d2d5dd5 (old id 3438696)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/23320109?dopt=Abstract
date added to LUP
2013-02-04 13:28:16
date last changed
2019-02-20 05:05:36
@article{2265c551-976d-4362-926c-8abb7d2d5dd5,
  abstract     = {CO(2)-laser C-fibre evoked cortical potentials (LCEPs) is a potentially useful animal model for studies of pain mechanisms. A potential confounding factor when assessing analgesic effects of systemically administered drugs using LCEP is sedation. This study aims to clarify: 1) the relation between level of anaesthesia and magnitude of LCEP, 2) the effects of a sedative and an analgesic on LCEP and dominant EEG frequency 3) the effects of a sedative and analgesic on LCEP when dominant EEG frequency is kept stable. LCEP and EEG were recorded in isoflurane/nitrous-oxide anaesthetized rats. Increasing isoflurane level gradually reduced LCEPs and lowered dominant EEG frequencies. Systemic midazolam (10 μmol/kg) profoundly reduced LCEP (19% of control) and lowered dominant EEG frequency. Similarly, morphine 1 and 3 mg/kg reduced LCEP (39%, 12% of control, respectively) and decreased EEG frequency. When keeping the dominant EEG frequency stable, midazolam caused no significant change of LCEP. Under these premises, morphine at 3 mg/kg, but not 1 mg/kg, caused a significant LCEP reduction (26% of control). In conclusion, the present data indicate that the sedative effects should be accounted for when assessing the analgesic effects of drug. Furthermore, it is suggested that LCEP, given that changes in EEG induced by sedation are compensated for, can provide information about the analgesic properties of systemically administrated drugs.},
  articleno    = {e53966},
  author       = {Granmo, Marcus and Jensen, Tanja and Schouenborg, Jens},
  issn         = {1932-6203},
  language     = {eng},
  number       = {1},
  publisher    = {Public Library of Science},
  series       = {PLoS ONE},
  title        = {Nociceptive transmission to rat primary somatosensory cortex - comparison of sedative and analgesic effects.},
  url          = {http://dx.doi.org/10.1371/journal.pone.0053966},
  volume       = {8},
  year         = {2013},
}