Effects of Propofol General Anesthesia on Olfactory Relearning

Sci Rep. 2016 Sep 15:6:33538. doi: 10.1038/srep33538.

Abstract

How general anesthesia interferes with sensory processing to cause amnesia remains unclear. Here, we show that activation of a learning-associated immediate early gene in rat olfactory cortices is uninterrupted by propofol, an intravenous general anesthetic with putative actions on the inhibitory GABAA receptors. Once learned under anesthesia, a novel odor can no longer re-activate the same high-level transcription programming during subsequent conscious relearning. Behavioral tests indicate that the animals' ability to consciously relearn a pure odorant, first experienced under general anesthesia, is indeed compromised. In contrast, when a mixture of two novel odorants is first experienced under anesthesia and then relearned consciously in pairs with one of the components, the animals show a deficit in relearning only the component but not the mixture. Our results reveal a previously unknown mechanism of unconscious memory due to irreplaceable neuronal commitment under general anesthesia and support the notion that general anesthesia acts at stages beyond cellular coding to disrupt sensory integration for higher-order association.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Anesthesia, General*
  • Animals
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Choice Behavior / drug effects
  • Cognition / drug effects
  • Consciousness / drug effects
  • Learning*
  • Male
  • Memory / drug effects
  • Odorants
  • Olfactory Pathways / drug effects
  • Olfactory Pathways / physiology*
  • Piriform Cortex / drug effects
  • Piriform Cortex / metabolism
  • Propofol / pharmacology*
  • Rats, Sprague-Dawley
  • Transcription, Genetic / drug effects

Substances

  • Basic Helix-Loop-Helix Transcription Factors
  • Npas4 protein, rat
  • Propofol