This R01 project will advance our understanding of the brainstem neural circuits that generate and control breathing behavior in humans and all mammals. Breathing is an integral part of cardiopulmonary physiology and understanding its neural origins has significant implications for human health. Rhythmic breathing movements begin during embryonic development and emanate from coordinated activity in brainstem respiratory neurons. One key population of rhythm-generating neurons is contained in a site called the preB"tzinger complex (preB"tC). The discovery of the preB"tC made possible many powerful experiments that could be performed in vitro, and led to our contemporary understanding of the neurophysiology of respiration. Nevertheless, critical questions remain unanswered. Given the heterogeneity of respiratory-related and non-respiratory neurons in the preB"tC, can we discover which neurons are the key rhythm generators? If rhythmogenic neurons can be identified (and we argue that indeed they can), then can we ascertain the cellular, synaptic, and molecular-level mechanisms that underlie rhythm generation? Finally, the importance of peptidergic modulation of respiratory rhythm has been widely recognized in the past decade, but its underlying biophysical mechanisms remain incompletely understood. This project seeks answers to these specific questions by studying the preB"tC in thin brainstem slice preparations in vitro.
SPECIFIC AIM 1 will evaluate the cellular composition of the preB"tC. Transgenic mouse models will be used to apply fluorescent tags to genetically distinct sub-populations, and then selectively and serially lesion them to test their respective roles in rhythmogenesis.
SPECIFIC AIM 2 will examine the synaptic-dendritic active membrane properties that generate inspiratory-related bursts.
SPECIFIC AIM 3 will investigate whether presynaptic depression of excitatory transmission contributes to burst termination.
SPECIFIC AIM 4 is designed to complement SPECIFIC AIM 3 by examining the postsynaptic membrane properties that also act to terminate inspiratory bursts. Finally, SPECIFIC AIM 5 will determine the ion channels that underlie respiratory modulation by key neuropeptides (and other neuromessengers). The new knowledge acquired during this project will aid in the treatment and prophylaxis of breathing disorders that result from failures in the brain and central nervous system. Moreover, studying a measurable behavior like breathing under controlled in vitro conditions helps reveal important principles that link neurons, synapses, and molecules to full-scale physiological behaviors, which will be of great interest in neuroscience as well as cardiopulmonary physiology.

Public Health Relevance

Breathing is a vital human behavior that is essential to maintain homeostasis and life itself. This project will advance our understanding of the brainstem neural circuits that generate and control breathing rhythms by analyzing their function at multiple levels including: neuron type (i.e., genotype), cellular properties, ion channels, synaptic receptors, and intracellular signaling. The new knowledge obtained will serve as a foundation for the treatment and prevention of respiratory disorders with a central neural etiology, and elucidate circuit-level properties that underlie rhythmic motor behaviors in general.

National Institute of Health (NIH)
Research Project (R01)
Project #
Application #
Study Section
Respiratory Integrative Biology and Translational Research Study Section (RIBT)
Program Officer
Laposky, Aaron D
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
College of William and Mary
Schools of Arts and Sciences
United States
Zip Code
Wang, Xueying; Hayes, John A; Revill, Ann L et al. (2014) Laser ablation of Dbx1 neurons in the pre-Bötzinger complex stops inspiratory rhythm and impairs output in neonatal mice. Elife 3:e03427
Ruangkittisakul, Araya; Kottick, Andrew; Picardo, Maria C D et al. (2014) Identification of the pre-Bötzinger complex inspiratory center in calibrated "sandwich" slices from newborn mice with fluorescent Dbx1 interneurons. Physiol Rep 2:
Nordman, Jacob C; Phillips, Wiktor S; Kodama, Nathan et al. (2014) Axon targeting of the alpha 7 nicotinic receptor in developing hippocampal neurons by Gprin1 regulates growth. J Neurochem 129:649-62
Guinamard, R; Hof, T; Del Negro, C A (2014) The TRPM4 channel inhibitor 9-phenanthrol. Br J Pharmacol 171:1600-13
Tupal, Srinivasan; Huang, Wei-Hsiang; Picardo, Maria Cristina D et al. (2014) Atoh1-dependent rhombic lip neurons are required for temporal delay between independent respiratory oscillators in embryonic mice. Elife 3:e02265
Picardo, Maria Cristina D; Weragalaarachchi, Krishanthi T H; Akins, Victoria T et al. (2013) Physiological and morphological properties of Dbx1-derived respiratory neurons in the pre-Botzinger complex of neonatal mice. J Physiol 591:2687-703
Wang, Xueying; Hayes, John A; Picardo, Maria Cristina D et al. (2013) Automated cell-specific laser detection and ablation of neural circuits in neonatal brain tissue. J Physiol 591:2393-401
Guinamard, Romain; Simard, Christophe; Del Negro, Christopher (2013) Flufenamic acid as an ion channel modulator. Pharmacol Ther 138:272-84
Dunmyre, Justin R; Del Negro, Christopher A; Rubin, Jonathan E (2011) Interactions of persistent sodium and calcium-activated nonspecific cationic currents yield dynamically distinct bursting regimes in a model of respiratory neurons. J Comput Neurosci 31:305-28
Del Negro, Christopher A; Hayes, John A; Rekling, Jens C (2011) Dendritic calcium activity precedes inspiratory bursts in preBotzinger complex neurons. J Neurosci 31:1017-22

Showing the most recent 10 out of 12 publications