Direct presynaptic regulation of GABA/glycine release by kainate receptors in the dorsal horn: An ionotropic mechanism

Geoffrey A. Kerchner, Guo Du Wang, Chang Shen Qiu, James E. Huettner, Min Zhuo

Research output: Contribution to journalArticlepeer-review

97 Scopus citations

Abstract

In the spinal cord dorsal horn, excitatory sensory fibers terminate adjacent to interneuron terminals. Here, we show that kainate (KA) receptor activation triggered action potential-independent release of GABA and glycine from dorsal horn interneurons. This release was transient, because KA receptors desensitized, and it required Na+ entry and Ca2+ channel activation. KA modulated evoked inhibitory transmission in a dose-dependent, biphasic manner, with suppression being more prominent. In recordings from isolated neuron pairs, this suppression required GABAB receptor activation, suggesting that KA-triggered GABA release activated presynaptic GABAB autoreceptors. Finally, glutamate released from sensory fibers caused a KA and GABAB receptor-dependent suppression of inhibitory transmission in spinal slices. Thus, we show how presynaptic KA receptors are linked to changes in GABA/glycine release and highlight a novel role for these receptors in regulating sensory transmission.

Original languageEnglish
Pages (from-to)477-488
Number of pages12
JournalNeuron
Volume32
Issue number3
DOIs
StatePublished - Nov 8 2001

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