Insulin Signaling in Bupivacaine-induced Cardiac Toxicity: Sensitization during Recovery and Potentiation by Lipid Emulsion

Anesthesiology. 2016 Feb;124(2):428-42. doi: 10.1097/ALN.0000000000000974.


Background: The impact of local anesthetics on the regulation of glucose homeostasis by protein kinase B (Akt) and 5'-adenosine monophosphate-activated protein kinase (AMPK) is unclear but important because of the implications for both local anesthetic toxicity and its reversal by IV lipid emulsion (ILE).

Methods: Sprague-Dawley rats received 10 mg/kg bupivacaine over 20 s followed by nothing or 10 ml/kg ILE (or ILE without bupivacaine). At key time points, heart and kidney were excised. Glycogen content and phosphorylation levels of Akt, p70 s6 kinase, s6, insulin receptor substrate-1, glycogen synthase kinase-3β, AMPK, acetyl-CoA carboxylase, and tuberous sclerosis 2 were quantified. Three animals received Wortmannin to irreversibly inhibit phosphoinositide-3-kinase (Pi3k) signaling. Isolated heart studies were conducted with bupivacaine and LY294002-a reversible Pi3K inhibitor.

Results: Bupivacaine cardiotoxicity rapidly dephosphorylated Akt at S473 to 63 ± 5% of baseline and phosphorylated AMPK to 151 ± 19%. AMPK activation inhibited targets downstream of mammalian target of rapamycin complex 1 via tuberous sclerosis 2. Feedback dephosphorylation of IRS1 to 31 ± 8% of baseline sensitized Akt signaling in hearts resulting in hyperphosphorylation of Akt at T308 and glycogen synthase kinase-3β to 390 ± 64% and 293 ± 50% of baseline, respectively. Glycogen accumulated to 142 ± 7% of baseline. Irreversible inhibition of Pi3k upstream of Akt exacerbated bupivacaine cardiotoxicity, whereas pretreating with a reversible inhibitor delayed the onset of toxicity. ILE rapidly phosphorylated Akt at S473 and T308 to 150 ± 23% and 167 ± 10% of baseline, respectively, but did not interfere with AMPK or targets of mammalian target of rapamycin complex 1.

Conclusion: Glucose handling by Akt and AMPK is integral to recovery from bupivacaine cardiotoxicity and modulation of these pathways by ILE contributes to lipid resuscitation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • AMP-Activated Protein Kinases / drug effects
  • AMP-Activated Protein Kinases / metabolism
  • Anesthesia Recovery Period
  • Anesthetics, Local / toxicity*
  • Animals
  • Blotting, Western
  • Bupivacaine / toxicity*
  • Cardiotoxicity / metabolism
  • Disease Models, Animal
  • Drug Synergism
  • Fat Emulsions, Intravenous / metabolism
  • Fat Emulsions, Intravenous / pharmacology*
  • Glycogen Synthase Kinase 3 / drug effects
  • Glycogen Synthase Kinase 3 / metabolism
  • Glycogen Synthase Kinase 3 beta
  • Heart / drug effects*
  • In Vitro Techniques
  • Insulin / metabolism*
  • Myocardium / metabolism
  • Phosphatidylinositol 3-Kinases / drug effects
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects*


  • Anesthetics, Local
  • Fat Emulsions, Intravenous
  • Insulin
  • Phosphatidylinositol 3-Kinases
  • Glycogen Synthase Kinase 3 beta
  • Gsk3b protein, rat
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3
  • AMP-Activated Protein Kinases
  • Bupivacaine