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Regulation of visceral sympathetic tone by A5 noradrenergic neurons in rodents
Author(s) -
Kanbar Roy,
Depuy Seth D.,
West Gavin H.,
Stornetta Ruth L.,
Guyenet Patrice G.
Publication year - 2011
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2010.198374
Subject(s) - hypercapnia , hypoxia (environmental) , stimulation , medicine , catecholaminergic cell groups , brainstem , vasoconstriction , catecholaminergic , endocrinology , sympathetic nervous system , carotid body , blood pressure , anesthesia , neuroscience , catecholamine , biology , chemistry , respiratory system , oxygen , organic chemistry
Non‐technical summary Patients suffering from obstructive sleep apnoea (OSA) experience repeated decreases in blood oxygen (hypoxia) and increases in CO 2 (hypercapnia) causing sleep disruption, cardiac over‐stimulation, intense vasoconstriction and, eventually, day‐time hypertension. Hypoxia and hypercapnia initiate these responses by activating the carotid bodies whereas hypercapnia also works in the central nervous system. In this study in anaesthetized rats we show that a group of noradrenergic neurons located in the lower brainstem (A5 neurons) are vigorously activated by carotid body stimulation and mildly affected by CO 2 . We also show that selective activation of the A5 neurons increases sympathetic tone to the viscera and we suggest that these catecholaminergic neurons contribute to the cardiovascular stimulation caused by acute hypoxia. The importance of the A5 neurons to acute hypoxic responses in the conscious state remains to be assessed and their contribution to the day‐time hypertension associated with OSA is also a matter for future research.