title: Endothelial NO synthase activity in nucleus tractus solitarii contributes to hypertension in spontaneously hypertensive rats.
abstract: NO is implicated as a major modulator of central nervous circuits regulating cardiovascular activity. Based on previous data, we hypothesized that overactivity of endothelial NO synthase (eNOS) within the nucleus tractus solitarii (NTS) could contribute to the hypertension in the spontaneously hypertensive rat (SHR). Using real-time PCR, we found that endogenous eNOS mRNA was greater in the NTS of mature, but not juvenile prehypertensive SHRs compared with aged-matched Wistar Kyoto (WKY) rats. To test the functional significance of this, we chronically blocked eNOS activity in the NTS in the adult SHR by in vivo adenoviral-mediated gene transfer of a dominant-negative form of eNOS; data were compared with WKY rats. This resulted in a fall in arterial pressure in the SHR but not WKY rats. In both rat strains, cardiac baroreceptor reflex gain and the high-frequency spectral component of heart rate variability increased. Thus, endogenous eNOS activity in the NTS plays a major role in determining the set point of arterial pressure in the SHR and contributes to maintaining high arterial blood pressure in this animal model of human hypertension.
authors.affiliation: Department of Physiology, Bristol Heart Institute, School of Medical Sciences, University of Bristol, Bristol, United Kingdom.
authors.forename: Hidefumi
authors.initials: H
authors.lastname: Waki
authors.forename: David
authors.initials: D
authors.lastname: Murphy
authors.forename: Song T
authors.initials: ST
authors.lastname: Yao
authors.forename: Sergey
authors.initials: S
authors.lastname: Kasparov
authors.forename: Julian F R
authors.initials: JF
authors.lastname: Paton
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D017704:Baroreflex; D001794:Blood Pressure; D006321:Heart / Q000503:physiopathology; D006339:Heart Rate; D006973:Hypertension / Q000378:metabolism / Q000503:physiopathology*; D052250:Nitric Oxide Synthase Type III / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017552:Solitary Nucleus / Q000201:enzymology*
chemical_list: D012333:RNA, Messenger; D052250:Nitric Oxide Synthase Type III