期刊
TOXICOLOGY LETTERS
卷 240, 期 1, 页码 1-9出版社
ELSEVIER IRELAND LTD
DOI: 10.1016/j.toxlet.2015.10.008
关键词
Bilirubin; Auditory; Inhibitory postsynaptic current (IPSC); Excitotoxicity; Patch-clamp
类别
资金
- National Key Basic Research Program of China [2014CB541705]
- National Natural Science Foundation of China [81470688, 81371092]
Hyperbilirubinemia is a common clinical phenomenon observed in human newborns. A high level of bilirubin can result in severe jaundice and bilirubin encephalopathy. However, the cellular mechanisms underlying bilirubin excitotoxicity are unclear. Our previous studies showed the action of gamma-aminobutyric acid (GABA)/glycine switches from excitatory to inhibitory during development in the ventral cochlear nucleus (VCN), one of the most sensitive auditory nuclei to bilirubin toxicity. In the present study, we investigated the roles of GABA(A)/glycine receptors in the induction of bilirubin hyperexcitation in early developing neurons. Using the patch clamp technique, GABA(A)/glycine receptor-mediated spontaneous inhibitory synaptic currents (sIPSCs) were recorded from bushy and stellate cells in acute brainstem slices from young mice (postnatal day 2-6). Bilirubin significantly increased the frequency of sIPSCs, and this effect was prevented by pretreatments of slices with either fast or slow Ca2+ chelators BAPTA-AM and EGTA-AM suggesting that bilirubin can increase the release of GABA/glycine via Ca2+-dependent mechanisms. Using cell-attached recording configuration, we found that antagonists of GABA(A) and glycine receptors strongly attenuated spontaneous spiking firings in P2-6 neurons but produced opposite effect in P15-19 neurons. Furthermore, these antagonists reversed bilirubin-evoked hyperexcitability in P2-6 neurons, indicating that excitatory action of GABA/glycinergic transmission specifically contribute to bilirubin-induced hyperexcitability in the early stage of development. Our results suggest that bilirubin-induced enhancement of presynaptic release GABA/Glycine via Ca2+-dependent mechanisms may play a critical role in mediating neuronal hyperexcitation associated with jaundice, implicating potential new strategies for predicting, preventing, and treating bilirubin neurotoxicity. (C) 2015 Elsevier Ireland Ltd. All rights reserved.
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