Effect of dietary sodium intake on central angiotensinergic pathways

• Published in: Autonomic neuroscience Vol. 98; no. 1; pp. 17 - 19
• Main Authors: DiBona, Gerald F, Jones, Susan Y
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 28.06.2002; Elsevier
• Subjects: Angiotensin Receptor Antagonists; Angiotensins - metabolism; Animals; Antihypertensive Agents - pharmacology; Benzimidazoles - pharmacology; Bicuculline - pharmacology; Biological and medical sciences; Blood Pressure - drug effects; Blood Pressure - physiology; Brain - metabolism; Central nervous system; Central neurotransmission. Neuromudulation. Pathways and receptors; Diet, Sodium-Restricted; Dietary sodium intake; Fundamental and applied biological sciences. Psychology; Kidney - innervation; Losartan - pharmacology; Medulla Oblongata - drug effects; Medulla Oblongata - physiology; Microinjections; Paraventricular Hypothalamic Nucleus - drug effects; Paraventricular Hypothalamic Nucleus - physiology; Rats; Receptor, Angiotensin, Type 1; Renal sympathetic nerve activity; Renin-Angiotensin System - physiology; Renin–angiotensin system; Sympathetic Nervous System - drug effects; Sympathetic Nervous System - physiology; Tetrazoles - pharmacology; Vertebrates: nervous system and sense organs; Renin–angiotensin system; Renal sympathetic nerve activity; Dietary sodium intake; Renin angiotensin system; Vertebrata; Mammalia; Rat; Sodium; Autonomic nervous system; Food intake; Rodentia; Angiotensin; Sympathetic nervous system
• ISSN: 1566-0702; 1872-7484
• DOI: 10.1016/S1566-0702(02)00023-1

The role of central angiotensinergic pathways in the cardiovascular regulation has been examined using the microinjection of angiotensin peptides and angiotensin receptor antagonists. However, in such studies, neither the overall nor the local level of activity of the renin–angiotensin system is generally known. Herein, physiological changes in the endogenous level of activity of the renin–angiotensin system were produced by alterations in the dietary sodium intake. Microinjection of the angiotensin II AT 1 receptor antagonists losartan or candesartan into the rostral ventrolateral medulla produced the bradycardic, depressor and renal sympathoinhibitory responses which were greater in low sodium diet rats with stimulated activity of the renin–angiotensin system than in high sodium diet rats with suppressed activity of the renin–angiotensin system activity. The renal sympathoexcitatory responses to activation of the paraventricular nucleus by microinjection of bicuculline, known to be dependent on the excitatory synaptic inputs to the rostral ventrolateral medulla mediated by AT 1 receptors, were greater in low sodium diet rats than in high sodium rats. These observations support the view that physiologically regulated angiotensin peptides of the brain origin exert a local paracrine or autocrine action on sites that influence the renal sympathetic nerve activity.