title: Reactivity of the mesenteric bed arteries of normotensive rats exposed to chronic social stress.
abstract: The aim of this study was to investigate the effects of chronic social stress on endothelium-dependent relaxation in the superior mesenteric artery (SMA) and its first branches (1MA) as well as on neurogenic contractions of SMA in adult, male Wistar-Kyoto (WKY) rats. Mesenteric arteries were isolated from control (living space: 480 cm(2)/rat) or stressed rats exposed to 8-week-lasting crowding stress (living space: 200 cm(2)/rat). Blood pressure (BP) and heart rate, determined by tail-cuff plethysmography, were not affected by crowding. Stress increased neurogenic contractions of SMA elicited by electrical stimulation of perivascular nerves and significantly elevated vasoconstriction induced by exogenous noradrenaline in SMA, without modulation of its endothelial function. In 1MA, nitric oxide (NO)-dependent component of endothelium-dependent relaxation to acetylcholine was investigated. In 1MA, stress failed to affect noradrenaline- and phenylephrine-induced vasoconstriction, total acetylcholine-induced relaxation as well as its NO-dependent and NO-independent components. Moreover, endothelium-independent sodium nitroprusside-induced relaxations of 1MA from the stressed rats did not differ from those of controls. In conclusion, chronic stress produced by crowding failed to induce an increase of BP, presumably because endothelial function of SMA and vascular function of small mesenteric arteries, which are rather important in BP regulation, remained preserved.
authors.affiliation: Institute of Normal and Pathological Physiology, Centre of Excellence for Examination of Regulatory Role of Nitric Oxide in Civilization Diseases, Slovak Academy of Sciences, Sienkiewiczova 1, 813 71 Bratislava, Slovak Republic. angelika.puzserova@savba.sk
authors.forename: Angelika
authors.initials: A
authors.lastname: Puzserova
authors.forename: Jozef
authors.initials: J
authors.lastname: Torok
authors.forename: Ruzena
authors.initials: R
authors.lastname: Sotnikova
authors.forename: Anna
authors.initials: A
authors.lastname: Zemancikova
authors.forename: Iveta
authors.initials: I
authors.lastname: Bernatova
mesh_terms: D000818:Animals; D001794:Blood Pressure; D003441:Crowding; D004730:Endothelium, Vascular / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000503:physiopathology*; D051381:Rats; D011921:Rats, Inbred WKY; D012920:Social Behavior Disorders / Q000503:physiopathology*; D013315:Stress, Psychological / Q000503:physiopathology*; D014655:Vascular Resistance