摘要:

Contributions of both the renin-angiotensin and immune systems to the aetiology of renal infarct hypertension were examined in Sprague-Dawley rats. Partial renal infarction was produced by ligating and sectioning two out of three branches of the left renal artery. The right kidney remained intact. Renal infarction resulted in rapid development of stable hypertension. One week following infarction, the plasma renin activity.(PRA) increased more than threefold. However, PRA returned to control levels 4 weeks after infarction. Chronic immunosuppressive therapy with cyclophosphamide at most only attenuated the development of renal infarct hypertension associated with this transient renin elevation. However, cyclophosphamide prevented the later maintenance phase of the hypertension, and could also completely reverse established infarct hypertension. Activation of the renin-angiotensin system plays a role in the onset of partial renal infarct hypertension, but an intact immune system is required for maintenance of the hypertension. It is hypothesized that immunological reactions against renal tissue maintain renal infarct hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Brain infarct size and behaviour were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY) 3 weeks after occlusion of the right middle cerebral artery in order to compare the effects of vascular occlusions on the normotensive and hypertensive cerebral vasculature. The brain tissue reduction, assessed by measuring the cross-sectional area of remaining tissue and weight of the cerebral hemispheres, was greater in SHR than in WKY (P < 0.01), Deficits in sensorimotor integration were highly correlated to the degree of brain damage (r = 0.91). Amphetamine induced no rotation asymmetry in normal rats, whereas lesioned rats rotated more ipsilaterally to the lesion (P < 0.05). Rotation asymmetry did not correlate with total infarct size. The more severe outcome after middle cerebral artery occlusion in SHR as opposed to WKY, can probably be explained by reduced collateral capacity secondary to the altered vascular design in hypertension.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

Recent interest has centred on the role of divalent cations in hypertension, particularly in relation to the renin-angiotensin system. This study was undertaken to determine the hypotensive effect of magnesium administration in relation to the state of activation of the renin-angiotensin system. The mean blood pressure (MBP) and heart rate (HR) response to either the acute intravenous administration of a pharmacological dose of MgSO4or vehicle was determined in conscious mineralocorticoid-salt (DOCA-salt, low-renin) and two-kidney, one clip renovascular, high-renin hypertensive rats. Baseline MBP was higher in the renovascular than in the DOCA-salt rats, while there was no difference in HR or serum Mg concentration between the two. Following administration of MgSO4, serum Mg increased equally in both the DOCA-salt (1.4 ± 0.8 to 4.9 ± 0.16 mEq/l;P< 0.001) and in the renovascular rats (1.8 ± 0.14 to 4.4 ± 0.27 mEq/l;P< 0.001). Magnesium administration significantly lowered MBP over the 1-h infusion in the DOCA-salt (167 ± 8 to 145 ± 5 mmHg,P< 0.001) but not the renovascular hypertensive rats (191 ± 5 to 183 ± 4, NS). We conclude that the blood pressure lowering effect of Mg is related, in part, to the state of activation of the renin-angiotensin system. The mechanism of this differential effect remains to be determined.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We have compared the cardiac performance of four groups of rats: normotensive control rats (NCR) and spontaneously hypertensive rats (SHR) not drinking alcohol, and NCR and SHR drinking 20% alcohol (NCR-A and SHR-A, respectively), over a period of 6–9 months.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID

摘要:

We measured food intake, body growth and transport of calcium and sodium by duodenum of female Dahl salt sensitive (DS) and salt resistant (DR) rat strains. Food intake and body growth were similar for DS and DR rats taking both 0.4 and 8% sodium chloride diets. Food intake increased with age up to 5 weeks and then remained constant despite continuing body growth. Comparing DS and DR rats fed the 0.4% sodium chloride diet at 6 and 11 weeks or the 8% sodium chloride diet at 6 weeks, transport of calcium and sodium were the same in both the DS and DR groups. Transport of calcium, but not sodium, was lower at 11 than at 6 weeks. Comparing simultaneous feeding of either 0.4 or 8% sodium chloride diets to 6-week old DS and DR rat strains, transport of calcium tended to be lower in animals fed the 8% as compared to the 0.4% sodium chloride diet, and the difference was significant for net 40Ca transport for DR rats. The DS rat fed on 8% sodium chloride had higher systolic blood pressure (SBP) than the DR rat. We conclude that growing DS and DR rats, ingesting equal amounts of food, do not differ in duodenal calcium and sodium transport measured by the everted sac technique. The response to feeding sodium chloride differs between strains: the high salt diet decreases net 40Ca transport in the DR but not the DS strain.

ISSN:0263-6352    

出版商:OVID    

年代:1988

数据来源: OVID