Newly Published
Perioperative Medicine  |   December 2017
Bupivacaine Indirectly Potentiates Glutamate-induced Intracellular Calcium Signaling in Rat Hippocampal Neurons by Impairing Mitochondrial Function in Cocultured Astrocytes
Author Notes
  • From the Department of Pharmacology, Institute of Chinese Integrative Medicine, Hebei Medical University, Shijiazhuang, China (Y.X., N.Z., W.Z., L.-M.R.); and the Department of Pharmacy, Hebei North University, Zhangjiakou, China (N.Z.).
  • Submitted for publication May 3, 2017. Accepted for publication October 27, 2017.
    Submitted for publication May 3, 2017. Accepted for publication October 27, 2017.×
  • Research Support: Support was provided by the National Science Foundation of China (No. 81573416; Beijing, China), the Ministry of Education (the Young Thousand Talent Program to Dr. W. Zhang; Beijing, China), the Hebei Natural Science Foundation (No. H2016206030; Shijiazhuang, China), and the High Talent Science Research Project of Education Bureau Hebei Province (No. GCC2014015; Shijiazhuang, China).
    Research Support: Support was provided by the National Science Foundation of China (No. 81573416; Beijing, China), the Ministry of Education (the Young Thousand Talent Program to Dr. W. Zhang; Beijing, China), the Hebei Natural Science Foundation (No. H2016206030; Shijiazhuang, China), and the High Talent Science Research Project of Education Bureau Hebei Province (No. GCC2014015; Shijiazhuang, China).×
  • Competing Interests: The authors declare no competing interests.
    Competing Interests: The authors declare no competing interests.×
  • Correspondence: Address correspondence to Dr. Lei-Ming Ren: Department of Pharmacology, Institution of Chinese Integrative Medicine, Hebei Medical University, 361 Zhongshan East Road, Shijiazhuang, 050017, P.R. China. ren-leiming@263.net. Information on purchasing reprints may be found at www.anesthesiology.org or on the masthead page at the beginning of this issue. Anesthesiology’s articles are made freely accessible to all readers, for personal use only, 6 months from the cover date of the issue.
Article Information
Perioperative Medicine / Central and Peripheral Nervous Systems / Pharmacology
Perioperative Medicine   |   December 2017
Bupivacaine Indirectly Potentiates Glutamate-induced Intracellular Calcium Signaling in Rat Hippocampal Neurons by Impairing Mitochondrial Function in Cocultured Astrocytes
Anesthesiology Newly Published on December 14, 2017. doi:10.1097/ALN.0000000000002003
Anesthesiology Newly Published on December 14, 2017. doi:10.1097/ALN.0000000000002003
Abstract

Background: Bupivacaine induces central neurotoxicity at lower blood concentrations than cardiovascular toxicity. However, central sensitivity to bupivacaine is poorly understood. The toxicity mechanism might be related to glutamate-induced excitotoxicity in hippocampal cells.

Methods: The intracellular free Ca2+ concentration ([Ca2+]i), mitochondrial membrane potential, and reactive oxygen species generation were measured by fluorescence and two-photon laser scanning microscopy in fetal rat hippocampal neurons and astrocytes.

Results: In astrocyte/neuron cocultures, 300 μM bupivacaine inhibited glutamate-induced increases in [Ca2+]i in astrocytes by 40% (P < 0.0001; n = 20) but significantly potentiated glutamate-induced increases in [Ca2+]i in neurons by 102% (P = 0.0007; n = 10). Ropivacaine produced concentration-dependent effects similar to bupivacaine (0.3 to 300 μM). Tetrodotoxin did not mimic bupivacaine’s effects. In pure cell cultures, bupivacaine did not affect glutamate-induced increases in [Ca2+]i in neurons but did inhibit increased [Ca2+]i in astrocytes. Moreover, bupivacaine produced a 61% decrease in the mitochondrial membrane potential (n = 20) and a 130% increase in reactive oxygen species generation (n = 15) in astrocytes. Cyclosporin A treatment suppressed bupivacaine’s effects on [Ca2+]i, mitochondrial membrane potential, and reactive oxygen species generation. When astrocyte/neuron cocultures were incubated with 500 μM dihydrokainic acid (a specific glutamate transporter–1 inhibitor), bupivacaine did not potentiate glutamate-induced increases in [Ca2+]i in neurons but still inhibited glutamate-induced increases in [Ca2+]i in astrocytes.

Conclusions: In primary rat hippocampal astrocyte and neuron cocultures, clinically relevant concentrations of bupivacaine selectively impair astrocytic mitochondrial function, thereby suppressing glutamate uptake, which indirectly potentiates glutamate-induced increases in [Ca2+]i in neurons.