Total sleep deprivation inhibits the neuronal nitric oxide synthase and cytochrome oxidase reactivities in the nodose ganglion of adult rats.
Sleep disorders are a form of stress associated with increased sympathetic activity, and they are a risk factor for the occurrence of cardiovascular disease. Given that nitric oxide (NO) may play an inhibitory role in the regulation of sympathetic tone, this study set out to determine the NO synthase (NOS) reactivity in the primary cardiovascular afferent neurons (i.e. nodose neurons) following total sleep deprivation (TSD). TSD was performed by the disc-on-water method. Following 5 days of TSD, all experimental animals were investigated for quantitative nicotinamine adenine dinucleotide phosphate-diaphorase (NADPH-d, a co-factor of NOS) histochemistry, neuronal NOS immunohistochemistry and neuronal NOS activity assay. In order to evaluate the endogenous metabolic activity of nodose neurons, cytochrome oxidase (COX) reactivity was further tested. All the above-mentioned reactivities were objectively assessed by computerized image analysis. The clinical significance of the reported changes was demonstrated by alterations of mean arterial blood pressure (MAP). The results indicated that in normal untreated rats, numerous NADPH-d/NOS- and COX-reactive neurons were found in the nodose ganglion (NG). Following TSD, however, both the labelling and staining intensity of NADPH-d/NOS as well as COX reactivity were drastically reduced in the NG compared with normal untreated ganglions. MAP was significantly higher in TSD rats (136+/-4 mmHg) than in normal untreated rats (123+/-2 mmHg). NO may serve as an important sympathoinhibition messenger released by the NG neurons, and decrease of NOS immunoexpression following TSD may account for the decrease in NOS content. In association with the reduction of NOS activity, a defect in NOS expression in the primary cardiovascular afferent neurons would enhance clinical hypertension, which might serve as a potential risk factor in the development of TSD-relevant cardiovascular disturbances.
Chang
Hung-Ming
HM
Department of Anatomy, Faculty of Medicine, Chung Shan Medical University, Taichung, and Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. anatomy@csmu.edu.tw
Wu
Un-In
UI
Lin
Tzer-Bin
TB
Lan
Chyn-Tair
CT
Chien
Wei-Ching
WC
Huang
Wei-Ling
WL
Shieh
Jeng-Yung
JY
D000818:Animals; D001794:Blood Pressure / Q000502:physiology; D002452:Cell Count; D003576:Electron Transport Complex IV / Q000378:metabolism*; D006973:Hypertension / Q000209:etiology; D008297:Male; D009252:NADPH Dehydrogenase / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D009620:Nodose Ganglion / Q000166:cytology / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D012892:Sleep Deprivation / Q000378:metabolism* / Q000503:physiopathology
D019001:Nitric Oxide Synthase; D009252:NADPH Dehydrogenase; D003576:Electron Transport Complex IV