Furosemide Elicits Nonuniform Reflex Responses Via Cardiac Sympathetic Afferents

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 1994-06, Vol.23 (6, Part 2), p.924-930
• Main Authors: Petersen, Jørgen S, Dibona, Gerald F
• Format: Article
• Language: English
• Subjects: Animals; Antihypertensive agents; Biological and medical sciences; Blood Pressure - drug effects; Cardiovascular system; Denervation; Dose-Response Relationship, Drug; Furosemide - pharmacology; Heart Conduction System - cytology; Heart Conduction System - drug effects; Heart Conduction System - physiology; Indomethacin - pharmacology; Injections; Lidocaine - pharmacology; Male; Medical sciences; Neurons, Afferent - drug effects; Neurons, Afferent - physiology; Pericardium; Pharmacology. Drug treatments; Rats; Rats, Sprague-Dawley; Reflex - drug effects; Sympathetic Nervous System - cytology; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiology; Vagotomy
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/01.HYP.23.6.924

To examine whether furosemide elicits a cardiorenal reflex response via stimulation of cardiac afferents, furosemide was administered intrapericardially in sinoaortic denervated rats. The role of vagal afferents was evaluated by intrapericardial (IPC) administration of furosemide before and after bilateral vagotomy. The role of cardiac sympathetic afferents was examined by IPC administration of furosemide before and after IPC lidocaine blockade in rats with bilateral vagotomy. Low-dose furosemide (10 μg) elicited renal sympathoinhibition, whereas high-dose furosemide (1000 μg) produced a rapid and transient change in efferent renal sympathetic nerve activity of either inhibitory (19/49, or 39%) or excitatory (30/49, or 61%) nature. The responses were not affected by vagotomy but were abolished by IPC lidocaine blockade. In rats with a renal sympathoinhibitory response to IPC administration of 1000 μg furosemide, both the hypotensive and sympathoinhibitory responses were inhibited by indomethacin, whereas indomethacin did not affect reflex responses in rats showing a renal sympathoexcitatory response to IPC injection of 1000 μg furosemide. We conclude that furosemide elicits a nonuniform reflex response mediated via cardiac sympathetic afferents of which the renal sympathoinhibitory response is dependent on intact cyclooxygenase function.