Effect of chronic social stress on nitric oxide synthesis and vascular function in rats with family history of hypertension.
Genetic predisposition and psychosocial stress are known risk factors in the aetiology of hypertension. The aim of this study was to investigate the as yet unknown role of nitric oxide (NO) in mechanisms of social stress-induced hypertension in rats with a family history of hypertension. Male adult rats used in the study were offspring of normotensive (Wistar) dams and spontaneously hypertensive sires. The rats were exposed to 6-week crowding stress (5 rats/cage, 200 cm2/rat). Control rats were kept four per cage (480 cm2/rat). Blood pressure was determined non-invasively on the tail. Basal blood pressure of all rats was 131 +/- 2 mm Hg. Crowding stress increased significantly blood pressure (p < 0.02 vs. basal value). Crowding had no influence on NO synthase activity in the left ventricle, adrenal glands and kidney. However, crowding stress reduced significantly NO synthase activity in the aorta by 37% (p < 0.01 vs. control). Acetylcholine-induced relaxation and noradrenaline-induced vasoconstriction of the femoral artery were reduced in stressed rats by 58% (p < 0.001) and 41% (p < 0.003), respectively. On balance then, the results indicate that chronic social stress produced by crowding was associated with reduced vascular NO synthesis and altered vascular function in adult borderline hypertensive rats of normotensive mothers.
Bernatova
Iveta
I
Institute of Normal and Pathological Physiology, Slovak Academy of Sciences, Sienkiewiczova 1, 813 71 Bratislava, Slovak Republic. Iveta.Bernatova@savba.sk
Csizmadiova
Zuzana
Z
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002908:Chronic Disease; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005263:Femoral Artery / Q000503:physiopathology; D006973:Hypertension / Q000209:etiology* / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis; D051381:Rats; D011918:Rats, Inbred SHR; D017208:Rats, Wistar; D013315:Stress, Psychological / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase