Anesthesia and analgesia
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Anesthesia and analgesia · Sep 2011
Hyperbaric oxygenation therapy alleviates chronic constrictive injury-induced neuropathic pain and reduces tumor necrosis factor-alpha production.
The development of hyperalgesia and allodynia after chronic constrictive injury (CCI) is associated with significantly increased tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Theoretically, if the production of TNF-α and/or IL-1β could be reduced, neuropathic pain syndrome may be alleviated. Recently, a beneficial effect of hyperbaric oxygenation therapy (HBOT) in the treatment of pain disorders has been suggested. Our present study was designed to examine the hypotheses that (1) CCI-induced neuropathic pain may be associated with increased production of TNF-α and IL-1β, (2) HBOT may alleviate CCI-induced neuropathic pain, and (3) the alleviated neuropathic pain may be associated with reduced production of TNF-α and/or IL-1β. ⋯ These data show that HBOT alleviates CCI-induced neuropathic pain and inhibits endoneuronal TNF-α production, but not IL-1β in CCI-induced neuropathic pain. Reduced TNF-α production may, at least in part, contribute to the beneficial effect of HBOT.
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Anesthesia and analgesia · Sep 2011
The median effective dose of ketamine and gabapentin in opioid-induced hyperalgesia in rats: an isobolographic analysis of their interaction.
Ketamine and gabapentin have been shown to prevent the delayed hyperalgesia induced by short-term use of systemic opioids. The mechanism of this action is believed to be likely at the spinal level, through an antagonism of the N-methyl-D-aspartate receptors for ketamine, and through a specific binding site for gabapentin. In this study, we sought to determine the nature of the interaction of these 2 mechanistically distinct antihyperalgesic drugs in a model of opioid-induced hyperalgesia in rats. The median effective antihyperalgesic doses of each drug and of their combination were first defined, to assess the nature of the interaction using an isobolographic analysis. ⋯ The isobolographic analysis demonstrated that the combination of the 2 drugs produces effective antihyperalgesia with a supraadditive (synergistic) action.
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Anesthesia and analgesia · Sep 2011
Ultrasound gel-nerve contact: an experimental animal histologic study.
Ultrasound (US) regional nerve block requires the use of gel applied over the skin. With subsequent needle insertion, some of the gel may adhere either on the shaft or within the needle lumen and may be carried to the perineural structures or intraneurally. We performed this experimental animal study to investigate the effects of US gel contact on the nerve histologic structure. ⋯ Histologic features after perineural exposure to US gel are rather nonspecific and likely of no clinical significance. However, further studies are needed to determine the effect of US gel injection on intraneural tissues.