Effects of Halothane and Isoflurane on Hyperexcitability of Spinal Dorsal Horn Neurons after Incision in the Rat

Kawamata, Mikito; Narimatsu, Eichi; Kozuka, Yuji; Takahashi, Toshiyuki; Sugino, Shigekazu; Niiya, Tomohisa; Namiki, Akiyoshi

doi:10.1097/00000542-200501000-00025

Cited by 9 publications

(5 citation statements)

References 33 publications

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“…Neuronal responses to a surgical incision were suppressed by 1.0 MAC of halothane and isoflurane to 47% and 66%, respectively, relative to 0 MAC in spinaltransected decerebrated rats (7). Neuronal responses to heat (51°C) were suppressed by 1.0 MAC of halothane to Figure 3A plotting initial response versus anesthetic concentration.…”

Section: Discussionmentioning

confidence: 93%

“…Such an interpretation of differential action is limited however, because halothane and isoflurane's action on neuronal responses over the 0 -0.8 MAC range are incompletely known. Whereas halothane depresses dorsal horn spinal neurons in this lower range, there are limited similar data for isoflurane (5)(6)(7). For example, depression of dorsal horn neurons by either anesthetic at small (0 -0.8 MAC) concentrations may provide a state of reduced sensorimotor transmission upon which further increases in anesthetic concentration (0.8 -1.2 MAC) can effectively block noxious stimulus-evoked movement.…”

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confidence: 99%

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The Differential Effects of Halothane and Isoflurane on Windup of Dorsal Horn Neurons Selected in Unanesthetized Decerebrated Rats

Mitsuyo

Dutton

Antognini

et al. 2006

Anesthesia & Analgesia

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Halothane and isoflurane, in the peri-minimum alveolar anesthetic concentration (MAC) range, exert differential effects on spinal nociceptive neurons, whereby halothane further depresses their responses from 0.8 to 1.2 MAC, whereas isoflurane does not. We presently investigated if these anesthetics differentially affect windup, the progressive increase in neuronal responses to repetitive noxious stimuli, over a broad concentration range from 0 to 1.2 MAC. In decerebrated rats, single-unit recordings were made from dorsal horn neurons exhibiting windup to 20 1-Hz C-fiber strength electrical stimuli. Halothane and isoflurane (0, 0.4, 0.8, and 1.2 MAC) were tested in a counterbalanced crossover protocol. Increasing halothane and isoflurane from 0 to 1.2 MAC progressively suppressed the response to the first stimulus, as well as summed responses to all stimuli (to 34% +/- 8% and 50% +/- 8%, respectively; P < 0.05). Absolute windup (summed response minus 20x the first response) was suppressed by both anesthetics from 0 to 0.8 MAC, with further depression by halothane but not isoflurane at 1.2 MAC. Responses of neurons isolated at 0 MAC were partially, but never totally, depressed at 0.8 MAC. The dose-dependent suppression of windup is consistent with reduced temporal summation of pain. Further depression at 1.2 MAC halothane, but not isoflurane, suggests different sites of immobilizing action for these two anesthetics. Immobility seems to not be mediated by severe anesthetic depression of a subpopulation of nociceptive neurons.

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Section: Discussionmentioning

confidence: 93%

mentioning

confidence: 99%

The Differential Effects of Halothane and Isoflurane on Windup of Dorsal Horn Neurons Selected in Unanesthetized Decerebrated Rats

Mitsuyo

Dutton

Antognini

et al. 2006

Anesthesia & Analgesia

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“…When the values of two successive TFL were very close with a difference within 0.5 s, anesthesia was regarded as stable and the average from the two was defined as ''basal latency''. Usually, 15-20 min was enough for reaching a stable measurement from our experience and those reported by others (Bing et al, 1991;Cuellar et al, 2004;Kawamata et al, 2005). The ''test latency'' was the same as that described in Section 2.2.…”

Section: Induction Period and Maintenance Period Of Anesthesiamentioning

confidence: 88%

A minimal stress model for the assessment of electroacupuncture analgesia in rats under halothane

Wen

Yeh

Shyu

et al. 2007

European Journal of Pain

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The use of anesthetics in acupuncture analgesia is controversial. We evaluate a steady-state light anesthesia model to test whether minimal stress manipulation and reliable measurement of analgesia could be simultaneously achieved during electroacupuncture (EA) in animals. A series of experiments were performed. Firstly, EA compliance and tail-flick latencies (TFL) were compared in rats under 0.1%, 0.3%, 0.5%, 0.7%, or 1.1% halothane for 120min. Under 0.5% halothane, TFL were then measured in groups receiving EA at intensity of 3, 10 or 20 volt (V), 1 or 2mg/kg morphine, 20V EA plus naloxone, or control. Subsequently, the effect of EA on formalin-induced hyperalgesia was tested and c-fos expression in the spinal dorsal horn was analyzed. Rats exhibited profound irritable behaviors and highly variable TFL under 0.1% or 0.3% halothane, as well as a time-dependent increase of TFL under 0.7% or 1.1% halothane. TFL remained constant at 0.5% halothane, and needle insertion and electrical stimulation were well tolerated. Under 0.5% halothane, EA increased TFL and suppressed formalin-induced hyperalgesia in an intensity-dependent and naloxone-reversible manner. EA of 20V prolonged TFL by 74%, suppressed formalin-induced hyperalgesia by 32.6% and decreased c-fos expression by 29.7% at the superficial and deep dorsal horn with statistically significant difference. In conclusion, 0.5% halothane provides a steady-state anesthetic level which enables the humane application of EA stimulus with the least interference on analgesic assessment. This condition serves as a minimal stress EA model in animals devoid of stress-induced analgesia while maintaining physiological and biochemical response in the experiment.

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“…Similar findings have been reported for halothane and isoflurane regarding the lack of effectiveness of these gases to reduce neuronal hyperexcitability in the dorsal horn after surgery in rats. 22 Other studies reported differential effects of halogenous anesthetics on windup phenomena and neuronal excitability in the dorsal horn 36 or the effects of halogenous anesthetics on wide-dynamic range neuronal activity in the dorsal horn. 37 One limitation of this work stems from a pharmacological viewpoint, that it would have been justified to have evaluated the effects of higher concentrations of sevoflurane.…”

Section: Discussionmentioning

confidence: 99%

“…8,[18][19][20] Halogenated anesthetics have in vitro anti-NMDA properties. [21][22][23][24] Other studies have shown that halogenated anesthetics induce hyperalgesia when administered at very low concentrations 25,26 and even decrease morphine analgesic effects. 25,27 However, in the context of current clinical practice, it is unresolved as to whether or not inhaled anesthetics elicit residual effects on postoperative hyperalgesia.…”

Section: Résumémentioning

confidence: 99%

Effects of sevoflurane on carrageenan- and fentanyl-induced pain hypersensitivity in Sprague-Dawley rats

Richebé

Rivalan

Rivat

et al. 2008

Can J Anesth/J Can Anesth

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Purpose Opioids are widely used for anesthesia but paradoxically induce postoperative pain hypersensitivity via N-methyl-D-aspartate (NMDA) receptor modulation. Sevoflurane effects on opioid-induced hyperalgesia have not been yet evaluated in vivo. Nevertheless, some experimental in vitro studies reported anti-NMDA receptor properties for sevoflurane. The aim of this study was to evaluate sevoflurane effects on fentanyl-induced hyperalgesia in opioid-naive rats and in rats with inflammatory pain. Methods Sevoflurane effects on hyperalgesia were evaluated in Sprague-Dawley rats: opioid-naive rats, rats treated with fentanyl (4 9 60 lg kg -1 ) and rats with inflammatory pain (carrageenan) treated with fentanyl (4 9 60 lg kg -1 ). On day zero, subcutaneous fentanyl injections were administered and inflammatory pain was induced with one carrageenan injection in one hind paw. Rats were exposed to low concentrations of sevoflurane (1.0 or 1.5%) on day zero prior to fentanyl injections and inflammatory pain induction, and for the duration of the fentanyl analgesic effect. The nociceptive threshold (Randall-Selitto test) was evaluated daily for 7 days. On day seven, naloxone was injected and the nociceptive threshold was assessed 5 min later. Results In rats without inflammatory pain but treated with fentanyl on day zero, sevoflurane 1.0% reversed the early (day zero) and long-lasting (day zero to day three) hyperalgesia classically described after high-doses of fentanyl (P \ 0.05). This sevoflurane concentration antagonized the hyperalgesia induced by naloxone on day seven (P = 0.33). In a second experiment in rats with inflammatory pain, exposure to low concentrations of sevoflurane (1.0 and 1.5%) did not reduce fentanyl-induced hyperalgesia (P [ 0.05), but nevertheless antagonized the naloxone induced hyperalgesia on day seven (P = 0.061). Conclusion Relatively low sevoflurane concentrations (1.0%) reverse fentanyl-induced hyperalgesia in rats without inflammatory pain. Nevertheless, the lack of effect of sevoflurane concentrations of 1.0% and 1.5% to oppose hyperalgesia following high-dose fentanyl and inflammatory pain suggests that sevoflurane anti-hyperalgesic properties are weak. RésuméObjectif Les opioı¨des sont largement utilise´s en anesthe´sie mais induisent paradoxalement une hypersensibiliteṕ ostope´ratoire a`la douleur via une modulation des re´cepteurs N-me´thyl-D-aspartate (NMDA). Les effets du

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Effects of Halothane and Isoflurane on Hyperexcitability of Spinal Dorsal Horn Neurons after Incision in the Rat

Cited by 9 publications

References 33 publications

The Differential Effects of Halothane and Isoflurane on Windup of Dorsal Horn Neurons Selected in Unanesthetized Decerebrated Rats

The Differential Effects of Halothane and Isoflurane on Windup of Dorsal Horn Neurons Selected in Unanesthetized Decerebrated Rats

A minimal stress model for the assessment of electroacupuncture analgesia in rats under halothane

Effects of sevoflurane on carrageenan- and fentanyl-induced pain hypersensitivity in Sprague-Dawley rats

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