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Isoflurane and propofol have similar effects on spinal neuronal windup at concentrations that block movement

Kevin P Ng1, Joseph F Antognini

  • 1Department of Anesthesiology and Pain Medicine, University of California, Davis, Davis, California 95616, USA.

Anesthesia and Analgesia
|November 24, 2006
PubMed
Abstract

Insights

Isoflurane and propofol show similar effects on spinal cord neuronal windup. However, higher concentrations of isoflurane (1.2 minimum alveolar concentration) enhanced neuronal windup at a 1 Hz stimulus frequency.

Area of Science:

  • Neuroscience
  • Anesthesiology

Background:

  • Neuronal windup is a key mechanism in spinal cord sensitization.
  • Isoflurane and propofol are common anesthetic agents with potential effects on neuronal excitability.

Purpose of the Study:

  • To compare the effects of isoflurane and propofol on neuronal windup in the rat spinal cord.
  • To test the hypothesis that propofol depresses neuronal windup more than isoflurane.

Main Methods:

  • A cross-over design study in rats (n=13) using single-unit recordings in the lumbar cord.
  • Administration of isoflurane (0.8 and 1.2 minimum alveolar concentration) and propofol (0.8 and 1.2 effective dose 50%).
  • Electrical stimulation at 0.1, 1, and 3 Hz, with analysis of neuronal responses and absolute windup.

Main Results:

  • Neither isoflurane nor propofol significantly altered total neuronal action potentials across tested frequencies and doses (P=NS).
  • Absolute windup was significantly enhanced at 1.2 MAC isoflurane for the 1 Hz stimulus (P < 0.01).
  • No significant differences in absolute windup were observed between isoflurane and propofol at comparable doses.

Conclusions:

  • Isoflurane and propofol exhibit comparable effects on spinal cord neuronal windup.
  • A higher concentration of isoflurane demonstrated an enhancement of absolute windup at a specific stimulus frequency (1 Hz).

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