Impaired spatial learning and memory after sevoflurane-nitrous oxide anesthesia in aged rats is associated with down-regulated cAMP/CREB signaling

PLoS One. 2013 Nov 15;8(11):e79408. doi: 10.1371/journal.pone.0079408. eCollection 2013.

Abstract

Neurocognitive deficits arising from anesthetic exposure have recently been debated, while studies have shown that the phosphorylation of cyclic AMP response element-binding protein (CREB) in the hippocampus is critical for long-term memory. To better understand the neural effects of inhalational anesthetics, we studied the behavioral and biochemical changes in aged rats that were exposed to sevoflurane (Sev) and nitrous oxide (N2O) for 4 h. Eighteen-month-old rats were randomly assigned to receive 1.3% sevoflurane and 50% nitrous oxide/50% oxygen or 50% oxygen for 4 h. Spatial learning and memory were tested with the Morris water maze 48 h after exposure, and the results showed that sevoflurane-nitrous oxide exposure induced a significant deficit in spatial learning acquisition and memory retention. Experiments revealed that the cAMP and pCREB levels in the dorsal hippocampus were decreased in rats with anesthetic exposure in comparison with control rats 48 h after anesthesia as well as 15 min after the probe trial, but there were no significant differences in CREB expression. Besides these, the current study also found the DG neurogenesis significantly decreased as well as neuronal loss and neuronal apoptosis increased in the hippocampus of rats exposed to Sev+N2O. The current study demonstrated that down-regulation of cAMP/CREB signaling, decrease of CREB-dependent neurogenesis and neuronal survival in the hippocampus contributed to the neurotoxicity and cognitive dysfunction induced by general anesthesia with sevoflurane-nitrous oxide.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anesthetics, Inhalation / adverse effects*
  • Animals
  • Cyclic AMP Response Element-Binding Protein / genetics
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Male
  • Maze Learning / drug effects
  • Memory / drug effects
  • Methyl Ethers / adverse effects*
  • Nitrous Oxide / adverse effects*
  • Random Allocation
  • Rats
  • Rats, Sprague-Dawley
  • Sevoflurane
  • Signal Transduction / drug effects
  • Space Perception / drug effects*

Substances

  • Anesthetics, Inhalation
  • Cyclic AMP Response Element-Binding Protein
  • Methyl Ethers
  • Sevoflurane
  • Nitrous Oxide

Grants and funding

This project was supported by Shanghai Natural Science Fund (10ZR1406500). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript