Acetylcholine release from the midbrain interpeduncular nucleus during anesthesia

Kyoji Taguchi, Marcia J. Andresen, D. Hentall

Research output: Contribution to journalArticlepeer-review

11 Scopus citations

Abstract

An exceptional local rise in metabolism during general anesthesia has been noted previously in the ventral midbrain's highly cholinoceptive interpeduncular nucleus (IPN). We report here a functional correlate. Increased interstitial acetylcholine (ACh) was measured in the IPN of rats through chronically implanted microdialysis probes upon anesthesia by inhalation of 3% halothane (mean 1425% of pre-anesthesia baseline at 30min, n=5) and by i.p. injection of 100mg kg-1 ketamine (mean 387%, n=6). With 50mg kg-1 i.p. pentobarbital (n=8), ACh either climbed or fell repeatably in each animal, a positive correlation (p<0.05) emerged between the baseline pre-anesthetized level and the percentage change after 60min. Mapping of the brainstem under ketamine (n=2) or pentobarbital (n=3) anesthesia showed the ACh source to lie in the IPN. We conclude that physiological responses to the chemically and pharmacologically diverse anesthetics halothane and ketamine, and probably also to pento-barbital, converge to enhance the output of the IPN.

Original languageEnglish (US)
Pages (from-to)789-792
Number of pages4
JournalNeuroreport
Volume2
Issue number12
DOIs
StatePublished - Dec 1991

Keywords

  • Halothane
  • Ketamine
  • Microdialysis
  • Pentobarbital

ASJC Scopus subject areas

  • Neuroscience(all)

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