Zusammenfassung
Der Liquor cerebrospinalis von Ratten enthält Angiotensinogen in hoher Konzentration. Nach Injektion von 3500fach angereichertem menschlichem Gehirnrenin in die Hirnventrikel von Ratten stieg die Konzentration von Angiotensin I von unmeßbar niedrigen Werten auf 147,9±18,8 fMol pro ml Liquor an.
Der mittlere arterielle Blutdruck änderte sich dabei von 93±2,4 mm Hg auf 107±3,7 mmHg.
Der Blutdruckanstieg konnte durch intraventrikuläre Gabe des Angiotensin II Rezeptorenblockers Saralasin rückgängig gemacht werden.
Die intraventrikuläre Injektion von Cathepsin D hatte keinen Effekt auf den arteriellen Blutdruck, und die Angiotensin I Konzentration im Liquor blieb unterhalb des Meßbereiches des Radioimmunoassays.
Wir schließen daraus, daß Gehirnrenin unter physiologischen Bedingungen in vivo Angiotensin I von endogenem Gehirnangiotensinogen abspaltet. Angiotensin I wird zu Angiotensin II umgewandelt und führt zum Blutdruckanstieg.
Summary
Cerebrospinal fluid (CSF) of rats contains high angiotensinogen concentrations. When 3500-fold purified renin from human brain was injected into the brain ventricles of rats, angiotensin I concentrations increased from undetectable levels to 147.9±18.8 fMol per ml CSF.
In parallel, mean arterial blood pressure increased from 93±2.4 mm Hg to 107±3.7 mm Hg.
The increase in blood pressure could be abolished by intraventricular administration of saralasin, a blocker of angiotensin II receptors.
Intraventricular injection of cathepsin D had no effect on arterial blood pressure and the angiotensin I concentration in CSF remained below detection limits of the radioimmunoassay.
We conclude that brain renin acts on endogenous brain angiotensinogen under physiological in vivo conditions to form angiotensin I. The latter is converted to angiotensin II and leads to biological effects, i.e. increase of blood pressure.
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Rettig, R., Speck, G., Simon, W. et al. In vivo enzyme activity of purified human brain renin. Klin Wochenschr 56 (Suppl 1), 43–45 (1978). https://doi.org/10.1007/BF01477451
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DOI: https://doi.org/10.1007/BF01477451