Title

VISUALIZATION OF A NEUROTRANSMITTER SWITCH DURING THE DEVELOPMENT OF HEARING

Presenter Information

Alison Hixon

Presentation Type

Presentation

Abstract

We investigated the development of the medial nucleus of the trapezoid body (MNTB) and the lateral superior olive (LSO), two brainstem nuclei involved sound localization. Many physical and chemical cellular interactions occur in LSO and MNTB neurons during early development. Although the development of these nuclei is poorly understood, dynamic changes occur in a subset of inhibitory neurons in LSO and MNTB. Although these inhibitory neurons use the neurotransmitters GABA and glycine and are essential to the proper functioning of the auditory system, they have not yet been systematically visualized during development in auditory brainstem nuclei. We tracked the development of inhibitory neuron subtypes in LSO and MNTB using transgenic mice in which yellow fluorescent protein (YFP) or green fluorescent protein (GFP) is driven by promoters for the calcium binding protein parvalbumin (PV) or the GABA synthesizing enzyme GAD65, respectively. Using antibody labeling and fluorescent microscopy, we compared the number and distribution of fluorescent cells in LSO and MNTB prior to, during, and after the onset of hearing for each strain of mouse. Although the transition from a GABAergic to glycinergic phenotypes has been described physiologically, this is the first study that uses transgenic mice to visualize this transition. The inhibitory neurotransmitter GABA plays an important role before the onset of hearing, but glycine is important after the onset of hearing. Investigating these inhibitory neurons increases our knowledge of sound processing in the auditory system.

Category

Life Sciences

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Apr 15th, 4:20 PM Apr 15th, 4:40 PM

VISUALIZATION OF A NEUROTRANSMITTER SWITCH DURING THE DEVELOPMENT OF HEARING

UC 326

We investigated the development of the medial nucleus of the trapezoid body (MNTB) and the lateral superior olive (LSO), two brainstem nuclei involved sound localization. Many physical and chemical cellular interactions occur in LSO and MNTB neurons during early development. Although the development of these nuclei is poorly understood, dynamic changes occur in a subset of inhibitory neurons in LSO and MNTB. Although these inhibitory neurons use the neurotransmitters GABA and glycine and are essential to the proper functioning of the auditory system, they have not yet been systematically visualized during development in auditory brainstem nuclei. We tracked the development of inhibitory neuron subtypes in LSO and MNTB using transgenic mice in which yellow fluorescent protein (YFP) or green fluorescent protein (GFP) is driven by promoters for the calcium binding protein parvalbumin (PV) or the GABA synthesizing enzyme GAD65, respectively. Using antibody labeling and fluorescent microscopy, we compared the number and distribution of fluorescent cells in LSO and MNTB prior to, during, and after the onset of hearing for each strain of mouse. Although the transition from a GABAergic to glycinergic phenotypes has been described physiologically, this is the first study that uses transgenic mice to visualize this transition. The inhibitory neurotransmitter GABA plays an important role before the onset of hearing, but glycine is important after the onset of hearing. Investigating these inhibitory neurons increases our knowledge of sound processing in the auditory system.