Subtle differences in synaptic transmission in medial nucleus of trapezoid body neurons between wild-type and Fmr1 knockout mice

Title

Subtle differences in synaptic transmission in medial nucleus of trapezoid body neurons between wild-type and Fmr1 knockout mice

Creator

Lu Yong

Publisher

Brain Research

Date

2019
2019-08

Description

In animal models for fragile X syndrome where the gene for fragile X mental retardation protein is knocked out (Fmr1 KO), neurotransmission in multiple brain regions shifts excitation/inhibition balance, resulting in hyperexcitability in neural circuits. Here, using whole-cell recordings from brainstem slices, we investigated synaptic transmission at the medial nucleus of trapezoid body (MNTB, a critical nucleus in the brainstem sound localization circuit), in Fmr1 KO and wild-type (WT) mice 2-3 weeks of age in both sexes. Surprisingly, neither synaptic excitation nor inhibition in KO neurons was significantly changed. The synaptic strength, kinetics, and short-term plasticity of synaptic excitation remained largely unaltered. Subtle differences were observed in response patterns, with KO neurons displaying less all-or-none eEPSCs. Similarly, synaptic inhibition mediated by glycine and GABA remains largely unchanged, except for a slower kinetics of mixed sIPSCs. In pharmacologically isolated glycinergic and GABAergic inhibition, no significant differences in synaptic strength and kinetics were detected between the two genotypes. These results demonstrate that at the cellular level synaptic transmission at MNTB is largely unaffected in Fmr1 KO mice by 2-3 weeks after birth, suggesting the existence of compensatory mechanisms that maintain the inhibitory output of MNTB to its targets in the auditory brainstem.

Subject

Fragile X syndrome; MNTB; Synaptic excitation; Synaptic inhibition

Rights

Article information provided for research and reference use only. All rights are retained by the journal listed under publisher and/or the creator(s).

Pages

95-103

Volume

1717

Citation

Lu Yong, “Subtle differences in synaptic transmission in medial nucleus of trapezoid body neurons between wild-type and Fmr1 knockout mice,” NEOMED Bibliography Database, accessed June 16, 2021, https://neomed.omeka.net/items/show/6349.

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