Quantitative and Qualitative Effects of Isoflurane on Movement Occurring after Noxious Stimulation

Antognini, Joseph F.; Wang, Xiao Wei; Carstens, Earl

doi:10.1097/00000542-199910000-00027

Cited by 34 publications

(23 citation statements)

References 22 publications

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“…Different anesthetic potencies of isoflurane on supraspinal or spinal structures have been reported. For isoflurane, the ratio of the righting-response ED50, an index of hypnosis, to MAC has been reported to have a mean value of 0.475 [6], and increasing the isoflurane concentration from 0.6 to 0.9 MAC was found to have little effect on the motor system [1]. In the present study, it was found that isoflurane inhalation at approximately two-thirds of MAC provided constant TF latency values on repeated testing.…”

Section: Discussionsupporting

confidence: 39%

The Effect of Sub-MAC Anesthesia and the Radiation Setting on Repeated Tail Flick Testing in Rats

et al. 2008

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Section: Discussionsupporting

confidence: 39%

The Effect of Sub-MAC Anesthesia and the Radiation Setting on Repeated Tail Flick Testing in Rats

et al. 2008

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“…Increasing halothane from 0.8 to 1.2 MAC further suppressed AUC windup to 34% of control, whereas increasing isoflurane did not further suppress AUC windup. The progressive depression of dorsal horn nociceptive processing at sub-MAC concentrations could partly account for the increase in stimulus frequency and intensity required to produce movement as isoflurane increases from 0 toward 1.0 MAC (14) and for the decrease in movement during supramaximal stimulation as isoflurane increases from 0.6 to 0.9 MAC (21).…”

Section: Discussionmentioning

confidence: 99%

“…In a crossover design (4), isoflurane or halothane was then administered in counterbalanced order such that each anesthetic was tested first in one half of the experiments. Windup responses were recorded during either isoflurane 0.6% (0.4 MAC), 1.1% (0.8 MAC), and 1.7% (1.2 MAC) or halothane 0.4% (0.4 MAC), 0.7% ( 0.8 MAC), and 1.1% (1.2 MAC); the approximate MAC fractions were based on previous studies from our laboratory (1,20,21). After changing the anesthetic concentration, we allowed equilibration times of at least 15 and 20 min for isoflurane and halothane, respectively, based on their blood-gas solubility coefficients.…”

Section: Methodsmentioning

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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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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“…After the completion of the animal preparation, the inspired gas was converted to a mixture of air and O 2 (30 to 35% total O 2 ) and the end-tidal isoflurane concentration was adjusted to 1.3 ± 0.1% (Antognini et al, 1999;Masamoto et al, 2007a). At first, preliminary mapping with OIS (pre-mapping) was performed for the localization of the forepaw area in the primary somatosensory cortex.…”

Section: Animal Preparationmentioning

confidence: 99%

Trial-by-trial relationship between neural activity, oxygen consumption, and blood flow responses

et al. 2008

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Trial-by-trial variability in local field potential (LFP), tissue partial pressure of oxygen (Po 2 ), cerebral blood flow (CBF) and deoxyhemoglobin-weighted optical imaging of intrinsic signals (OIS) were tested in the rat somatosensory cortex while fixed electrical forepaw stimulation (1.0 ms pulses with amplitude of 1.2 mA at a frequency of 6 Hz) was repeatedly applied. The changes in the cerebral metabolic rate of oxygen (CMRO 2 ) were also evaluated using a hypotension condition established by our group based on the administration of a vasodilator. Under normal conditions, CBF, Po 2 , and OIS showed positive signal changes (48%, 32%, and 0.42%, respectively) following stimulation. Over multiple trials, the CBF responses were well correlated with the integral of the LFP amplitudes (ΣLFP) (R mean = 0.78), whereas a lower correlation was found between Po 2 and ΣLFP (R mean = 0.60) and between OIS and ΣLFP (R mean = 0.54). Under the hypotension condition the LFP responses were preserved, but the CBF responses were suppressed and the Po 2 and OIS changes were negative (−12% and −0.28%, respectively). In this condition, the trial-by-trial variations in Po 2 and OIS were well correlated with the variability in ΣLFPs (R mean = −0.77 and −0.76, respectively), indicating a single trial coupling between CMRO 2 changes and ΣLFP. These findings show that CBF and CMRO 2 signals are more directly correlated with neural activity compared to blood-oxygen sensitive methods such as OIS and BOLD fMRI.

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Quantitative and Qualitative Effects of Isoflurane on Movement Occurring after Noxious Stimulation

Cited by 34 publications

References 22 publications

The Effect of Sub-MAC Anesthesia and the Radiation Setting on Repeated Tail Flick Testing in Rats

The Effect of Sub-MAC Anesthesia and the Radiation Setting on Repeated Tail Flick Testing in Rats

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

Trial-by-trial relationship between neural activity, oxygen consumption, and blood flow responses

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