Isoflurane action in spinal cord indirectly depresses cortical activity associated with electrical stimulation of the reticular formation

Joseph F. Antognini, Richard Atherley, Earl Carstens

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Anesthetics act in the spinal cord to ablate both movement and the ascending transmission of nociceptive information. We investigated whether a spinal cord action of isoflurane affected cortical activity as determined by the electroencephalogram desynchronization that occurs after electrical stimulation of the midbrain reticular formation (MRF). Six goats were anesthetized with isoflurane, and neck dissections were performed to permit differential isoflurane delivery to the head and torso. The electro-encephalogram was recorded before, during, and after focal electrical stimulation (0.05, 0.1, 0.2, 0.3, and 0.4 mA) in the MRF; in each animal, the brain isoflurane was maintained constant (≈1%). When the torso isoflurane was 0.3% ± 0.1%, the spectral edge frequency after MRF electrical stimulation (15.3 ± 1.7 Hz, averaged across all stimulus currents) was more than the spectral edge frequency when the torso isoflurane was 1.2% ± 0.2% (12.9 ± 1.0 Hz, averaged across all stimulus currents; P < 0.05). Bispectral index values were similarly affected: 60 ± 6 when torso isoflurane was low versus 53 ± 7 at high torso isoflurane (P < 0.05). These results suggest that a spinal depressant action of isoflurane on ascending somatosensory transmission can modulate reticulo-thalamocortical arousal mechanisms, hence possibly reducing anesthetic requirements for unconsciousness and amnesia.

Original languageEnglish (US)
Pages (from-to)999-1003
Number of pages5
JournalAnesthesia and Analgesia
Volume96
Issue number4
StatePublished - Apr 1 2003

Fingerprint

Reticular Formation
Isoflurane
Electric Stimulation
Spinal Cord
Torso
Anesthetics
Neck Dissection
Amnesia
Unconsciousness
Arousal
Goats
Electroencephalography
Head
Brain

ASJC Scopus subject areas

  • Anesthesiology and Pain Medicine

Cite this

Isoflurane action in spinal cord indirectly depresses cortical activity associated with electrical stimulation of the reticular formation. / Antognini, Joseph F.; Atherley, Richard; Carstens, Earl.

In: Anesthesia and Analgesia, Vol. 96, No. 4, 01.04.2003, p. 999-1003.

Research output: Contribution to journalArticle

@article{53d3ce5c65dd497d99149b7fe29a16c1,
title = "Isoflurane action in spinal cord indirectly depresses cortical activity associated with electrical stimulation of the reticular formation",
abstract = "Anesthetics act in the spinal cord to ablate both movement and the ascending transmission of nociceptive information. We investigated whether a spinal cord action of isoflurane affected cortical activity as determined by the electroencephalogram desynchronization that occurs after electrical stimulation of the midbrain reticular formation (MRF). Six goats were anesthetized with isoflurane, and neck dissections were performed to permit differential isoflurane delivery to the head and torso. The electro-encephalogram was recorded before, during, and after focal electrical stimulation (0.05, 0.1, 0.2, 0.3, and 0.4 mA) in the MRF; in each animal, the brain isoflurane was maintained constant (≈1{\%}). When the torso isoflurane was 0.3{\%} ± 0.1{\%}, the spectral edge frequency after MRF electrical stimulation (15.3 ± 1.7 Hz, averaged across all stimulus currents) was more than the spectral edge frequency when the torso isoflurane was 1.2{\%} ± 0.2{\%} (12.9 ± 1.0 Hz, averaged across all stimulus currents; P < 0.05). Bispectral index values were similarly affected: 60 ± 6 when torso isoflurane was low versus 53 ± 7 at high torso isoflurane (P < 0.05). These results suggest that a spinal depressant action of isoflurane on ascending somatosensory transmission can modulate reticulo-thalamocortical arousal mechanisms, hence possibly reducing anesthetic requirements for unconsciousness and amnesia.",
author = "Antognini, {Joseph F.} and Richard Atherley and Earl Carstens",
year = "2003",
month = "4",
day = "1",
language = "English (US)",
volume = "96",
pages = "999--1003",
journal = "Anesthesia and Analgesia",
issn = "0003-2999",
publisher = "Lippincott Williams and Wilkins",
number = "4",

}

TY - JOUR

T1 - Isoflurane action in spinal cord indirectly depresses cortical activity associated with electrical stimulation of the reticular formation

AU - Antognini, Joseph F.

AU - Atherley, Richard

AU - Carstens, Earl

PY - 2003/4/1

Y1 - 2003/4/1

N2 - Anesthetics act in the spinal cord to ablate both movement and the ascending transmission of nociceptive information. We investigated whether a spinal cord action of isoflurane affected cortical activity as determined by the electroencephalogram desynchronization that occurs after electrical stimulation of the midbrain reticular formation (MRF). Six goats were anesthetized with isoflurane, and neck dissections were performed to permit differential isoflurane delivery to the head and torso. The electro-encephalogram was recorded before, during, and after focal electrical stimulation (0.05, 0.1, 0.2, 0.3, and 0.4 mA) in the MRF; in each animal, the brain isoflurane was maintained constant (≈1%). When the torso isoflurane was 0.3% ± 0.1%, the spectral edge frequency after MRF electrical stimulation (15.3 ± 1.7 Hz, averaged across all stimulus currents) was more than the spectral edge frequency when the torso isoflurane was 1.2% ± 0.2% (12.9 ± 1.0 Hz, averaged across all stimulus currents; P < 0.05). Bispectral index values were similarly affected: 60 ± 6 when torso isoflurane was low versus 53 ± 7 at high torso isoflurane (P < 0.05). These results suggest that a spinal depressant action of isoflurane on ascending somatosensory transmission can modulate reticulo-thalamocortical arousal mechanisms, hence possibly reducing anesthetic requirements for unconsciousness and amnesia.

AB - Anesthetics act in the spinal cord to ablate both movement and the ascending transmission of nociceptive information. We investigated whether a spinal cord action of isoflurane affected cortical activity as determined by the electroencephalogram desynchronization that occurs after electrical stimulation of the midbrain reticular formation (MRF). Six goats were anesthetized with isoflurane, and neck dissections were performed to permit differential isoflurane delivery to the head and torso. The electro-encephalogram was recorded before, during, and after focal electrical stimulation (0.05, 0.1, 0.2, 0.3, and 0.4 mA) in the MRF; in each animal, the brain isoflurane was maintained constant (≈1%). When the torso isoflurane was 0.3% ± 0.1%, the spectral edge frequency after MRF electrical stimulation (15.3 ± 1.7 Hz, averaged across all stimulus currents) was more than the spectral edge frequency when the torso isoflurane was 1.2% ± 0.2% (12.9 ± 1.0 Hz, averaged across all stimulus currents; P < 0.05). Bispectral index values were similarly affected: 60 ± 6 when torso isoflurane was low versus 53 ± 7 at high torso isoflurane (P < 0.05). These results suggest that a spinal depressant action of isoflurane on ascending somatosensory transmission can modulate reticulo-thalamocortical arousal mechanisms, hence possibly reducing anesthetic requirements for unconsciousness and amnesia.

UR - http://www.scopus.com/inward/record.url?scp=0037377948&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0037377948&partnerID=8YFLogxK

M3 - Article

VL - 96

SP - 999

EP - 1003

JO - Anesthesia and Analgesia

JF - Anesthesia and Analgesia

SN - 0003-2999

IS - 4

ER -