Remodeling of cardiomyocytes and their branches in juvenile, adult, and senescent spontaneously hypertensive rats and Wistar Kyoto rats: Comparative morphometric analyses by scanning electron microscopy

1999 ◽  
Vol 14 (1) ◽  
pp. 15-28 ◽  
Author(s):  
Makoto Okabe ◽  
Keishiro Kawamura ◽  
Fumio Terasaki ◽  
Tetsuya Hayashi
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto Rats ◽  
Morphometric Analyses ◽  
Wistar Kyoto ◽  
Scanning Electron

Contribution of Vascular Nitric Oxide to Basal Blood Pressure in Conscious Spontaneously Hypertensive Rats and Normotensive Wistar Kyoto Rats

1995 ◽  
Vol 89 (2) ◽  
pp. 177-182 ◽  
Author(s):  
Naoyoshi Minami ◽  
Yutaka Imai ◽  
Jun-Ichiro Hashimoto ◽  
Keishi Abe
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Mean Arterial Pressure ◽  
Methyl Ester ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Spontaneously Hypertensive ◽  
Wistar Kyoto Rats ◽  
Basal Blood Pressure ◽  
Wistar Kyoto

1. The aim of this study was to clarify the extent to which vascular nitric oxide contributes to basal blood pressure in conscious spontaneously hypertensive rats and normotensive Wistar Kyoto rats. 2. The contribution of vascular nitric oxide to maintenance of blood pressure was estimated by measuring the pressor response to an intravenous injection of nitric oxide synthase inhibitor, Nω-l-arginine methyl ester, given after serial injections of captopril, vasopressin V1-receptor antagonist (V1-antagonist) and ganglion blocker (pentolinium) in conscious spontaneously hypertensive and Wistar Kyoto rats aged 20–28 weeks. To estimate the ‘amplifier property’ of hypertrophied vasculature in spontaneously hypertensive rats, which is known to modulate pressor responses, the lower blood pressure plateau after serial injections of captopril, V1-antagonist and pentolinium and the maximum blood pressure elicited by subsequent injection of increasing doses of phenylephrine were also measured. 3. The serial injections of captopril, V1-antagonist and pentolinium decreased mean arterial pressure from 164 ± 9 mmHg to 67 ± 2 mmHg and from 117 ± 2 mmHg to 49 ± 1 mmHg in spontaneously hypertensive and Wistar Kyoto rats respectively. The subsequent injection of Nω-l-arginine methyl ester restored mean arterial pressure almost to its control levels in both spontaneously hypertensive and Wistar Kyoto rats. The absolute changes in mean arterial pressure elicited by Nω-l-arginine methyl ester were significantly greater in spontaneously hypertensive than in Wistar Kyoto rats (P < 0.01), but there was no significant difference in the responses to Nω-l-arginine methyl ester when they were expressed as percentages of either the lower blood pressure plateau or maximum blood pressure. 4. These results indicate that basal blood pressure in both spontaneous hypertensive and Wistar Kyoto rats is maintained by a balance between vascular nitric oxide and major pressor systems. They also suggest that the vasodilatory effect of vascular nitric oxide does not differ between spontaneously hypertensive and Wistar Kyoto rats, and that the increased pressor effect of Nω-l-arginine methyl ester in spontaneously hypertensive rats is due to a vascular amplifier mechanism.

Calmodulin levels in hypertensive rats

1985 ◽  
Vol 68 (4) ◽  
pp. 407-410 ◽  
Author(s):  
J. Higaki ◽  
T. Ogihara ◽  
Y. Kumahara ◽  
E. L. Bravo
Keyword(s):  
Intracellular Calcium ◽  
Spontaneously Hypertensive Rats ◽  
Hypertensive Rats ◽  
Deoxycorticosterone Acetate ◽  
Spontaneously Hypertensive ◽  
Calcium Dependent ◽  
Wistar Kyoto Rats ◽  
Regulatory Systems ◽  
Wistar Kyoto ◽  
The Brain

1. Intracellular calmodulin levels were measured by direct radioimmunoassay in spontaneously hypertensive rats (SHR) and Wistar—Kyoto rats (WKY). 2. Decreased calmodulin levels were demonstrated in the brain, heart, aorta and kidney of spontaneously hypertensive rats compared with those in Wistar—Kyoto rats. 3. Calmodulin levels in the brain were also decreased in deoxycorticosterone acetate (DOCA)-salt rats, but not changed significantly in the heart, aorta and kidney compared with those in Wistar—Kyoto rats. 4. These findings suggest that intracellular calcium-dependent regulatory systems are genetically disrupted in spontaneously hypertensive rats, but this is probably not an important factor in the development of hypertension.

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