Changes in Central and Peripheral Renin-Angiotensin System after Furosemide Injection

Abstract

To examine the effects of acute stimulation on the peripheral and central renin-angiotensin system, simultaneous sampling of blood and cerebrospinal fluid (CSF) for measurements of plasma renin activity (PRA), plasma angiotensin I-immnunoreactivity (PAng I-ir), plasma angiotensin II-immunoreactivity (PAng II-ir), plasma angiotensinogen and cerebrospinal fluid angiotensin II-ir (CSF Ang II-ir) and CSF angiotensinogen was carried out following intravenous injection of furosemide (5mg/kg) in conscious dogs. Administration of furosemide induced marked increases in PRA, Ang I-ir, PAng II-ir and CSF Ang II-ir, however, neither plasma nor CSF angiotensinogen was changed. Furthermore, a relatively large dose (20mg/kg/min) of intravenously infused synthetic Ang II for 20min produced a five-fold increase in PAng II-ir compared with no significant increase in CSF Ang II-ir In spite of significant suppression of PRA and PAng I-ir, there were no significant changes in either plasma or CSF angiotensinogen.
These results primarily suggest that the peripheral and the brain reninangiotensi n systems may be linked and that acute changes in the peripheral renin-angiotens in system do not alter either plasma or CSF angiotensinogen.