The Department of Physiology welcomes Dr. David Kline, Professor in the Department of Biomedical Sciences, Dalton Cardiovascular Research Center and Interdisciplinary Neuroscience Program, at the University of Missouri in Columbia, Missouri. Dr. Kline is a candidate for the Tenure Track Associate/Full Professor position in the Department of Physiology. Dr. Kline will present a Zoom seminar entitled “Astrocytes are crucial to nTS excitatory and inhibitory circuit activity and cardiorespiratory function” tomorrow, Friday, February 19, at 4:00pm as part of his interview process.
Dr. Kline’s laboratory focuses on the neuronal pathways within the cardiovascular, respiratory, and autonomic nervous systems. These vital systems operate to keep our bodies within “normal” physiological limits. When challenged with low oxygen (hypoxia), respiration, blood pressure, and heart rate increase to maintain arterial blood gas levels and perfusion of vital organs (e.g., the brain and the heart). This happens by activation of the chemoreceptor reflex. The baroreflex is also vital to maintaining constant blood pressure. Both reflex pathways involve activation of neurons in the peripheral and central nervous system. The latter occurs in the nucleus Tractus Solitarii (nTS), a major focus of his research. Determining the mechanism(s) of action in these reflex pathways during health and their modulation in disease is the goal of Dr. Kline’s research program.
In his seminar, Dr. Kline will concentrate on the brainstem nTS as the first central site for integration and modulation of viscerosensory reflexes. Glutamate (Glu) is the primary excitatory neurotransmitter released from visceral afferents in the nTS. Glu binds to postsynaptic ionotropic glutamate receptors (mGluRs), including postsynaptic Grp I receptors to induce a slower depolarization, or alternatively presynaptic Grp II or III receptors to limit terminal activity and attenuate release of Glu via autoreceptor mechanisms. GABA is the major inhibitory neurotransmitter in the nTS and originates from numerous interneurons where it binds to ionotropic GABAA and metabotropic GABAB receptors. The timing and effect of GluR and/or GABAR activation is guided not only by neurotransmitter concentration and spatial distribution of its receptors in the synaptic and extrasynaptic space, but also their position relative to uptake transports that remove extracellular Glu and GABA. In this study, Dr. Kline will discuss the role of astrocytic Glu and GABA transporters in controlling the balance of excitation and inhibition in the nTS and their influence on normal physiological function. Furthermore, he will show astrocytes are important in the manifestation of altered nTS circuit activity in an obstructive sleep apnea model. Take together, his data demonstrates astrocytes critically limit activation of excitatory and inhibitory receptors, their synaptic interaction, and thus neuronal activity to influence cardiorespiratory homeostasis and reflex responses.
Please contact Dr. Nathan Tipton (ntipton2) if you would like to receive Zoom call-in information.
We look forward to seeing everyone tomorrow at 4:00pm!