Cerebrospinal fluid angiotensin II in patients with essential hypertension.
We measured components of the cerebrospinal fluid renin-angiotensin system from patients with essential hypertension under different dietary sodium intakes. The cerebrospinal fluid concentration of angiotensin II (Ang II) from the patients on a normal-sodium diet was 1.36 +/- 0.41 fmol/ml (n = 5). Neither the inactive nor the active form of renin was detected by the enzymatic activity or by the immunoreactivity, whereas angiotensinogen was detected (38.6 +/- 3.1 pmol/ml, n = 5). The Ang II level remained unchanged even after incubation of the cerebrospinal fluid at 37 degrees C for 3 h. Further, when authentic Ang II was added to the cerebrospinal fluid followed by incubation for 3 h at 37 degrees C, more than 90% of the added Ang II remained unchanged. Thus, the cerebrospinal fluid Ang II level may be reflected by the activity of the brain Ang II-forming system, as it was not affected by the cerebrospinal fluid constituents. The circulating renin-angiotensin system was stimulated by sodium depletion, and the cerebrospinal fluid concentration of Ang II also increased significantly. Sodium depletion may stimulate the brain Ang-II forming system, as it does the circulating renin-angiotensin system.
Kawamura
M
M
Division of Hypertension and Nephrology, National Cardiovascular Center, Osaka, Japan.
Kawano
Y
Y
Yoshida
K
K
Imanishi
M
M
Akabane
S
S
Matsushima
Y
Y
Kuramochi
M
M
Shimamoto
K
K
Yamamoto
K
K
Ito
K
K
D000804:Angiotensin II / Q000134:cerebrospinal fluid*; D006801:Humans; D006973:Hypertension / Q000134:cerebrospinal fluid*; D012083:Renin / Q000097:blood; D012982:Sodium, Dietary / Q000008:administration & dosage
D012982:Sodium, Dietary; D000804:Angiotensin II; D012083:Renin