title: Prolonged attenuation of acetylcholine-induced phosphorylation of extracellular signal-regulated kinase 1/2 following sevoflurane exposure.
abstract: BACKGROUND
  Volatile anaesthetics are known to affect cholinergic receptors. Perturbation of cholinergic signalling can cause cognitive deficits. In this study, we wanted to evaluate acetylcholine-induced intracellular signalling following sevoflurane exposure.
  
  
  METHODS
  Pheochromocytoma12 PC12 cells were exposed to 4.6% sevoflurane for 2 h. Subsequently, Western blotting was used to measure acetylcholine-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK) 1/2 and basal Protein kinase B (AKT) phosphorylation.
  
  
  RESULTS
  After exposure, acetylcholine-induced ERK 1/2 phosphorylation was reduced to 58 ± 8% [95% confidence interval (CI): 38-77%, P = 0.003] compared with non-exposed controls. At 30 min after the end of sevoflurane administration [at 0.7% sevoflurane (0.102 mM)], ERK 1/2 phosphorylation remained reduced to 57 ± 7% (95% CI: 39-74%, P = 0.001) and was at 120 min [0.02% (0.003 mM] still reduced to 63 ± 10% (95% CI: 37-88%, P = 0.01), compared with control. At 360 min after exposure, acetylcholine-induced ERK 1/2 phosphorylation had recovered to 98 ± 16% (95% CI: 45-152%, P = 0.98) compared with control. In contrast, immediately after sevoflurane exposure, basal AKT phosphorylation was increased by 228 ± 37% (95% CI: 133-324%, P = 0.02) but had returned to control levels at 30 min after exposure, 172 ± 67% (95% CI: 0-356%, P = 0.34).
  
  
  CONCLUSIONS
  Sevoflurane exposure has differential effects on different intracellular signalling pathways. On one hand, we observed a prolonged attenuation of acetylcholine-induced ERK 1/2 phosphorylation that persisted even when sevoflurane concentrations close to detection level. On the other hand, basal AKT phosphorylation was increased twofold during sevoflurane exposure, with a rapid return to baseline levels after exposure. We speculate that the effects on acetylcholine-induced intracellular signalling observed in our in vitro model could be of relevance also for cholinergic signalling in vivo following sevoflurane exposure.
authors.affiliation: Department of Physiology and Pharmacology, Section for Anesthesiology and Intensive Care Medicine, Karolinska Institutet, Stockholm, Sweden. andreas.wiklund@ki.se
authors.forename: A
authors.initials: A
authors.lastname: Wiklund
authors.forename: D
authors.initials: D
authors.lastname: Gustavsson
authors.forename: A
authors.initials: A
authors.lastname: Ebberyd
authors.forename: E
authors.initials: E
authors.lastname: Sundman
authors.forename: G
authors.initials: G
authors.lastname: Schulte
authors.forename: M
authors.initials: M
authors.lastname: Jonsson Fagerlund
authors.forename: L I
authors.initials: LI
authors.lastname: Eriksson
mesh_terms: D000109:Acetylcholine / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D004305:Dose-Response Relationship, Drug; D006801:Humans; D007091:Image Processing, Computer-Assisted; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008738:Methyl Ethers / Q000494:pharmacology*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D016716:PC12 Cells; D010766:Phosphorylation / Q000187:drug effects; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects; D000077149:Sevoflurane; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D018685:Anesthetics, Inhalation; D008738:Methyl Ethers; D012333:RNA, Messenger; D011976:Receptors, Muscarinic; D000077149:Sevoflurane; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D000109:Acetylcholine