Although slow wave activity (SWA) in the EEG has been linked to homeostatic sleep regulation, the neurobiological substrate of sleep homeostasis is little understood. In three different species, we have identified a rare population of cortical GABAergic interneurons that expresses c-FOS only during sleep. These sleep-active cells express the enzyme neuronal nitric oxide synthase (nNOS) and NK1R, the receptor for Substance P. Cortical nNOS/NK1R neurons seem to monitor the homeostatic sleep drive that accumulates during wakefulness because the percentage of nNOS/NK1R cells that express cFOS during sleep is proportional to prior wake duration. Cortical nNOS/NK1R cells are exceptional among cortical GABAergic neurons in that they have widespread intracortical projections. We have proposed that cortical nNOS/NK1R neurons are critical for orchestrating EEG SWA during sleep through release of an amino acid transmitter (GABA), a peptidergic transmitter (Neuropeptide Y), and/or a gaseous transmitter (NO). Thus, cortical nNOS/NK1R neurons may be part of the long- sought neuroanatomical circuit underlying the sleep-dependent ?Process S? and may provide insight into the neural circuitry underlying homeostatic sleep regulation. Determination of the inputs to cortical nNOS/NK1R neurons will be central to understanding their regulation and function. In the present application, we will test the hypotheses that Substance P excites cortical nNOS neurons through NK1R and that cortical nNOS/NK1R neurons are both sufficient and necessary for propagation of EEG SWA. To address these hypotheses, we will use a combination of in vitro physiology, cellular pharmacology, functional neuroanatomy, microendoscopic Ca2+ imaging, optogenetic stimulation and inhibition in vitro and in vivo, and cell-specific ablation using both wildtype and multiple transgenic mouse strains. Together, these experiments will provide further insight into the afferent regulation of cortical nNOS/NK1R neurons, as well as the necessity and sufficiency of these cells for EEG SWA. The results will not only enhance our understanding of sleep/wake regulation, but may also have implications for understanding sleep disorders and neurological and psychiatric diseases involving the cerebral cortex.
This proposal will further our understanding of the neural circuitry and function of a rare population of cells in the cerebral cortex that are activated during sleep. These GABAergic neurons express the enzyme neuronal nitric oxide synthase (nNOS) and neurokinin receptor 1 (NK1R) and are the only phenotypically- defined cortical neuron population known to be active during sleep. We will determine whether specific afferent inputs regulate these ?sleep active? nNOS/NK1R cells and identify the receptors that mediate these effects. We will also assess the effects of selective activation or inhibition of these cells on brain physiology. The results will not only enhance our understanding of sleep/wake regulation, but may also have implications for understanding sleep disorders and neurological and psychiatric diseases involving the cerebral cortex.
| Williams, Rhîannan H; Vazquez-DeRose, Jacqueline; Thomas, Alexia M et al. (2018) Cortical nNOS/NK1 Receptor Neurons are Regulated by Cholinergic Projections From the Basal Forebrain. Cereb Cortex 28:1959-1979 |
| Williams, Rhîannan H; Black, Sarah W; Thomas, Alexia M et al. (2018) Excitation of Cortical nNOS/NK1R Neurons by Hypocretin 1 is Independent of Sleep Homeostasis. Cereb Cortex : |
| Gerashchenko, Dmitry; Pasumarthi, Ravi K; Kilduff, Thomas S (2017) Plasticity-Related Gene Expression During Eszopiclone-Induced Sleep. Sleep 40: |
| Black, Sarah Wurts; Yamanaka, Akihiro; Kilduff, Thomas S (2017) Challenges in the development of therapeutics for narcolepsy. Prog Neurobiol 152:89-113 |
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| Morairty, Stephen R; Dittrich, Lars; Pasumarthi, Ravi K et al. (2013) A role for cortical nNOS/NK1 neurons in coupling homeostatic sleep drive to EEG slow wave activity. Proc Natl Acad Sci U S A 110:20272-7 |
| Sunkin, Susan M; Ng, Lydia; Lau, Chris et al. (2013) Allen Brain Atlas: an integrated spatio-temporal portal for exploring the central nervous system. Nucleic Acids Res 41:D996-D1008 |
| Dittrich, Lars; Heiss, Jaime E; Warrier, Deepti R et al. (2012) Cortical nNOS neurons co-express the NK1 receptor and are depolarized by Substance P in multiple mammalian species. Front Neural Circuits 6:31 |
| Hirashima, Noriko; Tsunematsu, Tomomi; Ichiki, Kanako et al. (2011) Neuropeptide B induces slow wave sleep in mice. Sleep 34:31-7 |
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