Sympathetic Activity and Cardiac Adrenergic Receptors in One-Kidney, One Clip Hypertension in Rats

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 1984-09, Vol.6 (5 Part 1), p.654-659
• Main Authors: VLACHAKIS, NICOLAS D, RANSOM, FABIENNE, KOGOSOV, ELLA, WOODCOCK, ELIZABETH, ALEXANDER, NATALIE, MARONDE, ROBERT F
• Format: Article
• Language: English
• Subjects: Animals; Arterial hypertension. Arterial hypotension; Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Catecholamines - metabolism; Experimental diseases; Hypertension, Renal - metabolism; Hypertension, Renal - physiopathology; Male; Medical sciences; Methoxyhydroxyphenylglycol - analogs & derivatives; Methoxyhydroxyphenylglycol - analysis; Myocardium - analysis; Nephrectomy; Norepinephrine - analysis; Rats; Rats, Inbred Strains; Receptors, Adrenergic - analysis; Sympathetic Nervous System - physiopathology
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.6.5.654

The activity of the sympathetic nervous system, as measured by levels of plasma and cardiac catecholamines and catecholamine metabolites and the function of cardiac α- and β-adrenergic receptors, was evaluated at 3 days and 4 weeks after induction of one-kidney, one clip hypertension (1K1C) in the rat. At 3 days, the plasma level of norepinephrine (NE) was lower in the 1K1C group than the control group (p < 0.01), whereas epinephrine (E) and the metabolites dihydroxymandelic acid (DOMA), dihydroxyphenylglycol (DOPEG), and normetanephrine (NMN) were similar in both groups. In addition, cardiac content of catecholamines, their metabolites, and adrenergic receptors were similar in both groups. At 4 weeks, plasma levels of NE and DOPEG were lower (p < 0.01), whereas levels of DOMA and NMN were higher (p < 0.02 and p < 0.001, respectively) in the 1K1C group than the control group. Cardiac content of NE (p < 0.01), and DOPEG (p < 0.05) was significantly lower, whereas DOMA and NMN were significantly higher (p < 0.01) in the 1K1C group as compared to controls. In addition, cardiac density of both α- and β-adrenergic receptors was reduced in the 1K1C group, whereas receptor affinities were unchanged.We conclude that1) the decreased level of plasma NE at 3 days and 4 weeks in the 1K1C model may indicate reduced activity of the sympathetic nervous system during the developmental and established phases of 1K1C hypertension; or 2) the increased levels of the extraneuronal catecholamine metabolites DOMA and NMN and the decreased density of the cardiac adrenergic receptors at 4 weeks may indicate increased amounts of NE at postsynaptic receptor sites, which, in turn, may contribute to the maintenance of hypertension in 1K1C model.