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-irIn 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 reninangiotensin systems may be linked and that acute changes in the peripheral renin-angiotensin system do not alter either plasma or CSF angiotensinogen.

Antenatal betamethasone exposure is associated with lower ANG-(1–7) and increased ACE in the CSF of adult sheep

“…Localization of these peptidases on the BBM may be important because the apical membrane contacts the CSF and these exopeptidases could directly contribute to CSF peptide processing (Fig. 9) (20,62,75).…”

Differences in the Duration of Diuretic Effects and Impact on the Renin-Angiotensin-Aldosterone System of Furosemide in Healthy Dogs

“…In a previous report concerning patients with CHF who had been administered loop diuretics orally for more than 3 months, the plasma renin activity and norepinephrine concentrations were significantly higher with short-acting loop diuretics than with long-acting ones [32]. Although the plasma renin activity is immediately and temporally increased after intravenous administrations of furosemide in humans and dogs, it returns to baseline values over a few hours [14,21,25,30]. In contrast, the plasma renin activity increases progressively to a maximum level 120 min after oral administrations of furosemide [25].…”

“…Intravenous administration of furosemide markedly increased the plasma renin activity, norepinephrine concentration and angiotensin II concentration in the healthy dogs. After 120 min, the plasma renin activity decreased by half, but the plasma angiotensin II concentration remained high [30]. The plasma aldosterone concentration increased in response to furosemide; although this increase was similar following doses > 0.1 mg/kg, the time to peak aldosterone response was dose dependent [27].…”

Επιδραση Των Αναστολεων Του Ενζυμου Μετατροπης Της Αγγειοτασινης Στο Μεταβολισμο Του Μαγνησιου Και Του Ψευδαργυρου

“…Σκόπιμο είναι να αναφερθεί εδώ, ότι διάφορα πειραματικά δεδομένα συνηγορούν υπέρ της συμμετοχής της αγγειοτασίνης II σε μηχανισμούς που εμπλέκονται στην παθογένεση της υπέρτασης, όπως η ύπαρξη αυξημένων συγκεντρώσεων αγγειοτασίνης II στο ΕΝΥ σκύλων πασχόντων από νεφρογενή υπέρταση (61), η επαναφορά στο φυσιολογικό της αρτηριακής πίεσης σε υπερτασικούς επίμυες μετά έγχυση στο ΕΝΥ είτε αναστολέων της αγγεοτασίνης II είτε αναστολέων του ACE (62) και η τελευταία παρατηρηθείσα άμβλυνση ή προφύλαξη από πειραματική υπέρταση, που επιτυγχάνεται μέσω πρόκλησης βλαβών σε περιοχές του εγκεφάλου που περιέχουν υποδοχείς αγγειοτασίνης II (63).…”