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Optogenetic Methods To Stimulate Gamma Motor Neuron Axons Ex Vivo, Apoorva Karekal, Remie Mandawe, Cameron Chun, Sai Kiran Byri, Danitza Cheline, Serena Ortiz, Shawn Hochman, Katherine A. Wilkinson

Faculty Research, Scholarly, and Creative Activity

It is challenging to stimulate gamma motor neurons, which are important regulators of muscle spindle afferent function, without also recruiting alpha motor neurons. Here, we test the feasibility of stimulating gamma motor neuron axons using optogenetics in two transgenic mouse lines. We used an ex vivo muscle–nerve preparation in adult mice to monitor muscle spindle afferent firing, which should increase in response to gamma motor neuron-induced lengthening of the sensory region of the muscle spindle. A force transducer measured alpha motor neuron-mediated twitch contractions. Blue LED light (470 nm; 1–5 mW) was delivered via a light guide to the sciatic …

Htr1b Is Necessary For Normal Retinal Function In Mice, Solomon E Gibson, Xiaofeng Tao, Guofu Shen, Justin Ma, Yong H Park, Maria Polo-Prieto, Benjamin J Frankfort

Faculty, Staff and Students Publications

Introduction: Serotonin (5-HT) is a neurotransmitter that is involved in retinal development, physiology, and vision, yet the specific contribution of individual 5-HT receptors to retinal function is poorly characterized. We identified 5-HT receptor 1B (Htr1b) as a potential key regulator of serotonergic signaling in the retina.

Methods: Htr1b localization was examined using RNAseq and in situ labeling. Retinal structure was assessed using histology and SD-OCT. Visual function was evaluated using optomotor behavioral experiments. Retinal function was characterized in vivo using electroretinography (ERG) and ex vivo using multielectrode array (MEA) recordings.

Results: Htr1b transcript and HTR1B protein localized primarily …