Role of endogenous opioids in respiratory development

University Of Michigan At Ann Arbor, Ann Arbor MI

Investigators

Abstract

PROJECT SUMMARY This K99/R00 Pathway to Independence Award is designed to allow me to achieve my long-term goal to establish an independent research career focused on respiratory circuit and breathing development. Newborn breathing conditions are common and can result in slow, irregular breathing which can be life-threatening. Understanding how neuromodulators, such as endogenous opioids, influence respiratory neuron and breathing development may reveal novel strategies for improving breathing during early life. Administering the opioid receptor antagonist naloxone has been shown to stimulate breathing in newborns but earlier studies may have missed a longer-acting role of endogenous opioids in respiratory neuron maturation. It is unknown if endogenous opioids influence the postnatal development of respiratory neurons and breathing. The overall hypothesis of this research is that endogenous opioids influence breathing and respiratory neuron development in a cell-type specific and developmental time point specific manner. To test this, I propose the following specific aims: Aim 1. Determine how endogenous opioids influence the physiology and morphology of developing brainstem respiratory neurons. Aim 2. Determine how mu opioid receptors and endogenous opioid peptides influence breathing during development. To accomplish these aims, I will use mice with whole-body deletion of mu-opioid receptors and the opioid peptide enkephalin. Brain slice electrophysiology and immunohistochemistry will be used to understand how altering endogenous opioids impacts the physiology and morphology of respiratory neurons, respectively (Aims 1a,b). I will evaluate breathing in awake mice with whole-body deletion of mu opioid receptors or enkephalin over a developmental time course (Aim 2a). I will also measure breathing in mice with medulla- and pons-targeted deletion of mu opioid receptors or enkephalin (Aim 2b). Finally, I will determine the timing and location of endogenous opioid release using a genetically- encoded opioid sensor in brainstem tissue from mice at different developmental time points (Aim 2c). I will receive training in brain slice electrophysiology in neonatal mice, opioid pharmacology, in vivo breathing measurements, advanced live confocal imaging, and in utero microinjection to express a genetically-encoded opioid sensor in brainstem neurons in mouse embryos. This research will determine the fundamental role of endogenous opioids in respiratory neuron maturation and breathing development. I will complete my research and career training plan under the mentorship of Drs. Erica Levitt and Lori Isom, as well as my mentoring team comprised of experts in the proposed techniques. Together, the proposed research and career training will help me achieve my long-term career goal of being an independent investigator studying the mechanisms of newborn breathing conditions.