Ultracytochemical localisation of Na+, K+-ATPase in cerebral endothelium in acute hypertension

1990 ◽  
Vol 80 (1) ◽  
pp. 7-11 ◽  
Author(s):  
S. Nag

1977 ◽  
Vol 37 (2) ◽  
pp. 141-152 ◽  
Author(s):  
E. Westergaard ◽  
B. van Deurs ◽  
H. E. Brøndsted


Author(s):  
Shams M. Ghoneim ◽  
Frank M. Faraci ◽  
Gary L. Baumbach

The area postrema is a circumventricular organ in the brain stem and is one of the regions in the brain that lacks a fully functional blood-brain barrier. Recently, we found that disruption of the microcirculation during acute hypertension is greater in area postrema than in the adjacent brain stem. In contrast, hyperosmolar disruption of the microcirculation is greater in brain stem. The objective of this study was to compare ultrastructural characteristics of the microcirculation in area postrema and adjacent brain stem.We studied 5 Sprague-Dawley rats. Horseradish peroxidase was injected intravenously and allowed to circulate for 1, 5 or 15 minutes. Following perfusion of the upper body with 2.25% glutaraldehyde in 0.1 M sodium cacodylate, the brain stem was removed, embedded in agar, and chopped into 50-70 μm sections with a TC-Sorvall tissue chopper. Sections of brain stem were incubated for 1 hour in a solution of 3,3' diaminobenzidine tetrahydrochloride (0.05%) in 0.05M Tris buffer with 1% H2O2.



Author(s):  
Reza Mohebbati ◽  
Yasamin Kamkar-De ◽  
Mohammad Naser Shafei

Objective: Our previous studies showed the antihypertensive effect of Ribes khorassanicum (R. khorassanicum), a medicinal herb growing in the North Khorasan Province of Iran. For further evaluation, the present study investigated the effect of n-hexane (HX), ethyl acetate (EA), and aqueous (AQ) fractions of hydroalcoholic R. khorassanicum extract on cardiovascular responses in angiotensin II (AngII) and NG-nitro-L-arginine methyl ester (L-NAME) hypertensive rats. Methods: Wistar rats were randomly divided into 11 groups (n=5): 1) control, 2) AngII (50 ng/kg, i.v), 3) AngII + losartan (10 mg/kg, i.p), 4) L-NAME (10 mg/kg, i.v), 5) L-NAME+ sodium nitroprusside (SNP) (50 mg/kg, i.p), 6,7,8) one dose of each fraction of R. khorassanicum (AQ/EA/HX (50 mg/kg, i.p)) +AngII, and 9,10,11) one dose of each fraction of R. khorassanicum (AQ/EA/HX (50 mg/kg, i.p)) + L-NAME. Treated rats received three fractions 30 min before the injection of L-NAME and AngII in separate groups. The cardiovascular parameters were recorded by the Power Lab instrument via an angiocath inserted into the femoral artery. The peak changes (∆) of mean arterial pressure (MAP), systolic blood pressure (SBP), and heart rate (HR) in treated groups were compared with those of the hypertensive and control groups. Result: AngII and L-NAME significantly increased ∆MAP and ∆SBP and attenuated by pretreatment of LOS and SNP, respectively. Pretreatment with polar (AQ) and semipolar (EA) fractions of R. khorassanicum reduced the peak changes of MAP and SBP in both AngII and L-NAME-treated groups. Only the fraction of the herb attenuated the HR increased in the L-NAME group. The HR in other groups did not demonstrate any significant difference. Conclusion: All fractions of R. khorassanicum have an antihypertensive effect. However, the effect of polar fractions is more salient. It is also conceivable that the antihypertensive effect of fractions is mostly mediated by the inhibition of AngII.



Circulation ◽  
1964 ◽  
Vol 30 (2s2) ◽  
Author(s):  
CHARLES P. MCCARTNEY


Hypertension ◽  
1982 ◽  
Vol 4 (2) ◽  
pp. 219-225 ◽  
Author(s):  
R J Cody ◽  
R F Rodger ◽  
L H Hartley ◽  
J Burton ◽  
J A Herd


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