title: Spectroscopic measurement of cortical nitric oxide release induced by ascending activation.
abstract: The transition from sleep to the awake state is regulated by the activation of subcortical nuclei of the brainstem (BS) and basal forebrain (BF), releasing acetylcholine and glutamate throughout the cortex and inducing a tonic state of neural activity. It has been suggested that such activation is also mediated by the massive and diffuse cortical release of nitric oxide (NO). In this work we have combined the spectroscopic measurement of NO levels in the somatosensory cortex of the cat through its marker methemoglobin, as well as two other hemodynamic markers (oxyhemoglobin--oxyHb--and deoxyhemoglobin--deoxyHb), together with the electrical stimulation of BS and BF--to induce an experimental transition from a sleep-like state to an awake-like mode. The results show an increase of NO levels either after BS or BF activation. The response induced by BS stimulation was biphasic in the three studied markers, and lasted for up to 30s. The changes induced by BF were monophasic lasting for up to 20s. The systemic blockade of NO production abolished the observed responses to BS whereas responses to BF stimulation were much less affected. These results indicate a crucial role for NO in the neuronal activation induced by the ascending systems.
authors.affiliation: Laboratory of Neuroscience and Motor Control (NEUROcom), Department of Medicine-INEF-Galicia, University of A Coruña and Institute of Biomedical Research (INIBIC), 15006 A Coruña, Spain. Electronic address: nespinosa@udc.es.
authors.forename: N
authors.initials: N
authors.lastname: Espinosa
authors.affiliation: Laboratory of Neuroscience and Motor Control (NEUROcom), Department of Medicine-INEF-Galicia, University of A Coruña and Institute of Biomedical Research (INIBIC), 15006 A Coruña, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Cudeiro
authors.affiliation: Laboratory of Neuroscience and Motor Control (NEUROcom), Department of Medicine-INEF-Galicia, University of A Coruña and Institute of Biomedical Research (INIBIC), 15006 A Coruña, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Mariño
mesh_terms: D000818:Animals; D066187:Basal Forebrain / Q000187:drug effects / Q000378:metabolism; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002415:Cats; D004558:Electric Stimulation; D000069280:Electrocorticography; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006454:Hemoglobins / Q000378:metabolism; D007191:Indazoles / Q000494:pharmacology; D008706:Methemoglobin / Q000378:metabolism; D008839:Microelectrodes; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000037:antagonists & inhibitors / Q000378:metabolism; D010108:Oxyhemoglobins / Q000378:metabolism; D012890:Sleep / Q000502:physiology; D013003:Somatosensory Cortex / Q000187:drug effects / Q000378:metabolism*; D013057:Spectrum Analysis; D014851:Wakefulness / Q000502:physiology
chemical_list: D004791:Enzyme Inhibitors; D006454:Hemoglobins; D007191:Indazoles; D010108:Oxyhemoglobins; D009569:Nitric Oxide; C100003:deoxyhemoglobin; D008706:Methemoglobin; D052248:Nitric Oxide Synthase Type I; C080122:7-nitroindazole
keywords: hemodynamics; sleep; somatosensory cortex; spectroscopy