Premium
Intravenous lipid emulsion modifies synaptic transmission in hippocampal CA1 pyramidal neurons after bupivacaine‐induced central nervous system toxicity
Author(s) -
Nie Hao,
Bai Zhixia,
Li Zhenzhou,
Yan Li,
Chen XueXin
Publication year - 2020
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.14924
Subject(s) - inhibitory postsynaptic potential , excitatory postsynaptic potential , neurotransmission , glutamate receptor , hippocampal formation , neuroscience , central nervous system , pharmacology , bupivacaine , toxicity , biology , chemistry , anesthesia , medicine , receptor
Abstract Local anesthetics can cause severe toxicity when absorbed systemically. Rapid intravenous administration of lipid emulsion (LE) is the standard of care for severe local anesthetic systemic toxicity which can cause cardiovascular and central nervous system (CNS) injury. The biological mechanism by which LE alleviates CNS toxicity remains unknown and understudied. Previous research has suggested that local anesthetics cause an imbalance of excitatory and inhibitory transmission in the brain. Therefore, this study aimed to observe the effect of LE on glutamate‐ and GABA‐induced currents in CA1 pyramidal neurons after bupivacaine‐induced CNS toxicity. We further characterized post‐synaptic modifications in these cells to try to elucidate the mechanism by which LE mediates bupivacaine‐induced CNS toxicity. Sprague–Dawley rats received intravenous bupivacaine (1 mg kg −1 min −1 ) in either normal saline or LE (or LE without bupivacaine) for 5 min. An acute brain slice preparation and a combination of whole‐cell patch clamp techniques and whole‐cell recordings were used to characterize action potential properties, miniature excitatory, and inhibitory post‐synaptic currents, and post‐synaptic modifications of excitatory and inhibitory transmission in CA1 hippocampal pyramidal neurons. The expression level of GABAA receptors were assessed with western blotting, whereas H&E and TUNEL staining were used to assess cytoarchitecture and apoptosis levels respectively. Bupivacaine treatment significantly increased the number of observed action potentials, whereas significantly decreasing rheobase, the first interspike interval (ISI), and hyperpolarization‐activated cation currents (Ih) in CA1 pyramidal neurons. LE treatment significantly reduced the frequency of miniature inhibitory post‐synaptic currents and enhanced GABA‐induced paired pulse ratio with 50 ms interval stimulation in bupivacaine‐treated rats. Regulation of GABAA levels is a promising mechanism by which LE may ameliorate CNS toxicity after systemic absorption of bupivacaine.