Effect of moxonidine on blood pressure and sympathetic tone in conscious spontaneously hypertensive rats

• Published in: European journal of pharmacology Vol. 362; no. 1; pp. 61 - 67
• Main Authors: Nurminen, Marja-Leena, Culman, Juraj, Haass, Markus, Chung, Oliver, Unger, Thomas
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 27-11-1998; Elsevier
• Subjects: Animals; Antihypertensive agents; Antihypertensive Agents - pharmacology; Biological and medical sciences; Blood pressure; Blood Pressure - drug effects; Cardiovascular system; Catecholamines - blood; Clonidine; Clonidine - pharmacology; Heart rate; Heart Rate - drug effects; Hypertension - physiopathology; Imidazoles - pharmacology; Male; Medical sciences; Moxonidine; Pharmacology. Drug treatments; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Splanchnic Nerves - drug effects; Spontaneously hypertensive rat (SHR), conscious; Sympathetic nerve activity; Sympathetic Nervous System - drug effects; Time Factors; Heart rate; Clonidine; Blood pressure; Spontaneously hypertensive rat (SHR), conscious; Sympathetic nerve activity; Moxonidine; Hypertension; Intravenous administration; Rat; Rodentia; Cardiovascular disease; Strain specificity; Sympathetic nervous system; Site of action; Splanchnic nerve; Vertebrata; Mammalia; Autonomic nervous system; Animal; Intracerebral administration; Antihypertensive agent; Genetics; α-Adrenergic receptor agonist; Hemodynamics; Mechanism of action
• ISSN: 0014-2999; 1879-0712
• DOI: 10.1016/S0014-2999(98)00726-2

The effects of moxonidine on blood pressure, heart rate and sympathetic tone were studied in conscious spontaneously hypertensive rats. Intravenous moxonidine (80 nmol) transiently increased blood pressure without affecting heart rate or splanchnic nerve activity. Moxonidine (20–80 nmol) given into the fourth cerebral ventricle dose-dependently lowered mean arterial pressure, heart rate and sympathetic outflow (maximally by 60±3 mm Hg, 148±10 beats min
−1 and 15±3 μV). Moxonidine was more effective by this route than after the injection into the lateral ventricle. Clonidine (20–80 nmol) produced an initial pressor response after both intracerebroventricular routes of administration. A decrease in blood pressure was observed only when clonidine was given into the fourth ventricle. Clonidine decreased heart rate and splanchnic nerve activity similarly like moxonidine when the substances were given into the fourth ventricle. The data imply that the hypotensive effect of moxonidine is related to central sympathoinhibition. The main site of this action appears to be in the brainstem region.