Anesthesia and analgesia
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Anesthesia and analgesia · Feb 2010
Reduced immobilizing properties of isoflurane and nitrous oxide in mutant mice lacking the N-methyl-D-aspartate receptor GluR(epsilon)1 subunit are caused by the secondary effects of gene knockout.
Until recently, the N-methyl-D-aspartate (NMDA) receptor was considered to possibly mediate the immobility produced by inhaled anesthetics such as isoflurane and nitrous oxide. However, new evidence suggests that the role of this receptor in abolition of the movement response may be less important than previously thought. To provide further evidence supporting or challenging this view, we examined the anesthetic potencies of isoflurane and nitrous oxide in genetically modified animals with established NMDA receptor dysfunction caused by GluRepsilon1 subunit knockout. ⋯ Our results confirm recent findings indicating no critical contribution of NMDA receptors to the immobility induced by isoflurane and nitrous oxide. In addition, they demonstrate the ability of changes secondary to genetic manipulation to affect the results obtained in global knockout studies.
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Anesthesia and analgesia · Feb 2010
Activation of spinal alpha-2 adrenoceptors, but not mu-opioid receptors, reduces the intrathecal N-methyl-D-aspartate-induced increase in spinal NR1 subunit phosphorylation and nociceptive behaviors in the rat.
A previous study from our laboratories showed that a significant reduction in spinal N-methyl-D-aspartate (NMDA) receptor NR1 subunit phosphorylation (pNR1) is associated with the antiallodynic effect produced by intrathecal (IT) injection of the alpha-2 adrenoceptor agonist, clonidine, in neuropathic rats. In this study, we determined whether the spontaneous pain and increased pNR1 expression induced by NMDA injection are reduced by IT injection of either clonidine or the mu-opioid receptor agonist, [D-Ala2, NMe-Phe4, Gly-ol5]-enkephalin (DAMGO). ⋯ These results demonstrate that the IT NMDA-induced increase in pNR1 expression and nociceptive behavior is significantly reduced by activation of alpha-2 adrenoceptors, but not mu-opioid receptors, in the spinal cord dorsal horn. Furthermore, these findings suggest that the modulation of spinal NR1 phosphorylation is linked to the effect of IT clonidine on postsynaptic neuronal activity.
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Anesthesia and analgesia · Feb 2010
Transgenic Alzheimer mice have a larger minimum alveolar anesthetic concentration of isoflurane than their nontransgenic littermates.
More than 12% of all people older than 65 yr have Alzheimer's disease. Because nothing is known about changes in demand of volatile anesthetics in this disease, we determined minimum alveolar anesthetic concentration (MAC) values of isoflurane in young and aged transgenic mice at risk of developing Alzheimer's disease (heterozygote APP23 mice with the "Swedish double mutation"). To differentiate between unspecific effects of the transgenic model and specific Alzheimer effects, we additionally evaluated MAC values in mice with the same genetic construct but without the Alzheimer's disease-causing Swedish double mutation (heterozygote APP51/16 mice). ⋯ The increased MAC value in aged heterozygote APP23 mice seems to be attributable to changes related to Alzheimer's disease.
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Anesthesia and analgesia · Feb 2010
What's new in obstetric anesthesia: the 2009 Gerard W. Ostheimer lecture.
This article summarizes the most relevant publications in obstetric anesthesiology from 2008. Forty-two articles were selected from a pool of several thousand in >70 English-language journals that were deemed as having the most impact on the practice of obstetric anesthesia.