Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Spontaneously hypertensive rats (SHR) and two strains of normotensive rats were compared with respect to enzymatic activities and calcium accumulation of plasma membrane and endoplasmic reticulum enriched fractions from their mesenteric arteries. Increased specific activities of alkaline phosphatase, 5'-nucleotidase and Mg2+-ATPase, and increased ATP-dependent calcium accumulation were found in 5- to 6-month-old SHR as compared to both strains fo age-matched normotensive rats. Alkaline phosphatase was increased in 33-day-old "early hypertensive" and 3- to 4-month-old SHR, but 5'-nucleotidase, Mg2+-ATPase, and calcium accumulation were not. Hydralazine treatment of young SHR partially prevented the increase of both alkaline phosphatase activity and blood pressure that develops with age. The relationship between alkaline phosphatase activity and the alterations in vascular reactivity associated with hypertension remains to be determined.
 ...
PMID:Relationship between blood pressure of spontaneously hypertensive rats and alterations in membrane properties of mesenteric arteries. 13 88

Subcellular fractions were obtained from aortas and ventricles of 6-month-old spontaneously hypertensive and normotensive Wistar rats by the use of differential and sucrose density gradient centrifugation. These preparations were studied to determine what alterations in calcium accumulation and enzymatic activities might be associated with hypertension. The total amount of calcium accumulation (in the presence of ATP and 17 muM free calcium) by the plasma membrane-enriched fraction from hypertensive rat aortas significantly less than that from normotensive rats (11.3 +/- 0.4 vs 16.2 +/- 1.6 mumol of calcium/g of protein, n = 8). In contrast the specific activities of the plasma membrane marker enzymes, 5'-nucleotidase and phosphodiesterase I, were 80% and 40% greater, respectively, in the hypertensive than in the normotensive fractions. On the other hand, various fractions from ventricles of the two types of rats were generally similar in enzyme activities and calcium accumulation. The decreased rate of relaxation of aortas from spontaneously hypertensive rats may be caused by the decreased rate of calcium transport demonstrated in this study.
 ...
PMID:Calcium accumulation and enzymatic activities of subcellular fractions from aortas and ventricles of genetically hypertensive rats. 17 22

Tissue wet weight as well as total protein content, 5'-nucleotidase activity, alkaline phosphatase activity and Ca2+ accumulation associated with a plasma membrane fraction isolated from spontaneous hypertensive rats (SHR) and rats with deoxycorticosterone (DOC) induced hypertension were investigated. Enhanced alkaline phosphatase activity and reduced ATP-dependent Ca2+ accumulation preceded the development of hypertension in SHR and these effects were reversed by DOC withdrawal followed by lowering of blood pressure in DOC hypertension. Increased arterial tissue wet weight and 5'-nucleotidase occurred only at the later stage of hypertension in SHR and the increased tissue wet weight was not reversed by DOC withdrawal in DOC hypertension. These observations suggest that enhanced alkaline phosphatase and reduced ATP-dependent Ca2+ uptake may play a significant role in initiating hypertension, while increased arterial wet weight and 5'-nucleotidase activities may participate in the maintenance of hypertension.
 ...
PMID:Abnormal biochemistry of vascular smooth muscle plasma membrane as an important factor in the initiation and maintenance of hypertension in rats. 50 50

Myocardial beta-adrenergic receptors were measured in membrane fractions from malignant SHRSP (M-SHRSP), SHRSP and WKY at different ages using [3H]-dihydroalprenolol (DHA) as a radioligand. The effects of isoproterenol (ISP) and chemical sympathectomy (6-hydroxydopamine treatment) on myocardial beta-receptors were also investigated in 10 and 24 week-old SHRS and WKY to examine the effects of hypertension and aging on receptor regulation. The number of myocardial beta-receptors in M-SHRSP at 4 weeks of age (W) and 10 W were significantly lower than those in age-matched SHRSP and WKY. In addition, the values in SHRSP at 4 and 10 W were significantly lower than those in age-matched WKY, but the numbers in SHRSP at 1, 24 and 48-54 W were not significantly different from age-matched WKY. The dissociation constant and activity of 5'-nucleotidase, which is a marker enzyme of cell membrane, were not significantly different among the three groups. ISP treatment significantly reduced the numbers of myocardial beta-receptors in 10 week-old SHRSP and 10 and 24 week-old WKY, but did not in 24 week-old SHRSP. The extent of this decrease of beta-receptors was lower in 10 week-old SHRSP than in 10 week-old WKY, and it was also lower in 24 week-old WKY than 10 week-old WKY. 6-Hydroxydopamine treatment significantly increased the number of myocardial beta-receptors in 10 and 24 week-old WKY, but did not in SHRSP. The extent of this increase of beta-receptors was lower in 24 week-old WKY than in 10 week-old WKY. These results suggest that the decrease of myocardial beta-receptor numbers in 4 and 10 week-old M-SHRSP and SHRSP does not appear to be genetically determined, but rather is caused by accelerated sympathetic activity, and that the regulation of myocardial beta-receptor is impaired in young and aged SHRSP and in aged WKY.
 ...
PMID:Effects of aging and drugs on myocardial beta-adrenergic receptors in M-SHRSP and SHRSP. 166 33

Na+-K+-ATPase activity and [3H]ouabain binding were studied in cardiac ventricles of single wrapped kidney and DOCA-NaCl hypertensive rats. It was found that the total Na+-K+-ATPase activity decreased in the DOCA-NaCl and kidney wrapped hypertensive rats. The decrease of enzyme activity in DOCA-NaCl hypertensive rats was due to extracellular fluid expansion induced by NaCl loading, as DOCA itself had no effect on the enzyme. All these alterations were specific for Na+-K+-ATPase, since Mg2+-ATPase and 5'-nucleotidase activities were unaffected. Binding studies with [3H]ouabain showed that the decrease in Na+-K+-ATPase activity was due to a reduction in the number of binding sites for ouabain rather than to a change of binding affinity. The reduced myocardial Na+-K+-ATPase activity observed in these two types of low renin hypertension, coupled with the observation of reduced vascular Na+ pump activity by others, suggests a common underlying defect in the cardiovascular Na+-K+ transport system of these hypertensive rats.
 ...
PMID:Myocardial Na+-K+-ATPase activity and [3H]ouabain binding sites in hypertensive rats. 255 24

The effect of changes in dietary sodium intake and of DOC hypertension on plasma atrial natriuretic peptide (PANP), and affinity (Kd) and number (Bmax) of vascular atrial natriuretic peptide binding sites was studied in the rat. There was no difference in PANP between rats on a high or low sodium intake [33.2 +/- 13.9 versus 30.7 +/- 17.3 (s.d.) fmol/ml], Kd [21.1 +/- 2.7 versus 19.7 +/- 4.5 (s.d.) pmol/l] or Bmax [14.8 +/- 1.6 versus 12.6 +/- 1.8 (s.d.) fmol/mg], respectively. In DOC hypertensive rats, PANP was increased compared with control animals [66.1 +/- 32.4 versus 26.4 +/- 9.9 (s.d.) fmol/ml, P less than 0.05] and there was apparent receptor down-regulation [Bmax 7.7 +/- 1.6 versus 19.7 +/- 3.5 (s.d.) fmol/mg, P less than 0.05] with no change in affinity [Kd 15.6 +/- 3.9 versus 18.3 +/- 3.2 (s.d.) pmol/l]. Down-regulation was confirmed when the membrane-bound enzyme 5'-nucleotidase, rather than protein, was used as an index of receptor number. These results suggest that in the rat, atrial natriuretic peptide (ANP) may be important in regulating cardiovascular homeostasis only following non-physiological alterations in sodium and volume status.
 ...
PMID:Rat atrial natriuretic peptide vascular receptor: effect of alterations in sodium balance and of DOC hypertension. 282 98

Inhibition of cardiovascular Na,K-pump activity has been shown to promote an increase in the contractile activity of myocardial and vascular smooth muscle and a consequent rise in blood pressure (BP). It has also been shown that vascular Na,K-pump activity and myocardial Na+K+ATPase activity [the energy source for active sodium (Na) and potassium (K) transport] are decreased in rats with various forms of low renin hypertension including rats with reduced renal mass-saline (RRM-saline) hypertension. In the present study, left ventricular Na+K+ATPase activity from rats with RRM-saline hypertension was found to be decreased in membranes prepared by two independent methods: deoxycholate, sodium iodide (Nal)-treated microsomal fractions (method 1) and membranes prepared by the hypotonic, lithium bromide (LiBr) method (method 2). Relative to RRM normotensive control rats which drank distilled water, myocardial Na+K+ATPase activity from RRM-saline drinking rats was decreased by 18.2% in membranes prepared by method 1 and 33.6% in membranes prepared by method 2. The apparent affinities of Na+K+ATPase for K and for ouabain were unaltered relative to controls in membranes prepared from these hypertensive rats by method 1, and the sialic acid content and 5'-nucleotidase activity (two putative sarcolemmal markers) were unaltered in membranes from the hypertensive rats, prepared by methods 1 and 2 respectively. The Mg2+ATPase activity of membranes prepared by method 1 was increased in the RRM-saline hypertensive rats but because it was not increased in membranes prepared by method 2 the former observation does not appear to be of any pathophysiological importance. In other experiments, hypertension was reversed in RRM-saline hypertensive rats by restricting their salt intake (substitution of distilled water for drinking).(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Decreased myocardial Na+K+ATPase activity in rats with reduced renal mass-saline hypertension. 300 89

In order to study the role of elastin in arteries with respect to hypertension and hypertensive arterial disease, aortic elastin content and elastase-like enzyme activity were examined and compared in stroke-prone spontaneously hypertensive rats (SHRSP), which show malignant hypertension, and Wistar-Kyoto normotensive rats (WKY). The elastin content was lower, whereas the elastase-like activity was higher at 20 weeks of age in SHRSP than in WKY, so that the aortic elastin/enzyme ratio of SHRSP was lower than that in WKY. These differences were not found at 6 weeks of age (prehypertensive stage). For SHRSP anti-hypertensive treatment resulted in lowering the elastase-like activity and in increasing the elastin content in comparison to untreated animals. The subcellular distribution of the elastase-like activity closely correlated with that of 5'-nucleotidase activity, a plasma membrane marker enzyme. The results indicate involvement of a smooth muscle plasmalemmal elastase-like enzyme in vascular connective tissue metabolism in health and possibly also its participation in hypertensive arterial diseases.
 ...
PMID:Elastin and elastase-like enzyme change in aorta of rat with malignant hypertension. 364 94

We have previously shown that Na+-K+ pump activity (ouabain-sensitive 86Rb uptake) is decreased in vascular tissue of animals with various forms of low renin hypertension. In the present study we measured Na+-K+-ATPase activity, the energy source for Na+-K+ pumping, in membrane fractions prepared from myocardial tissue of rats with chronic one-kidney, one-clip hypertension and their one-kidney normotensive controls. Membranes were prepared by two independent methods: microsomal fractions (method 1) and fractions prepared by the hypotonic LiBr method of Dhalla et al. (method 2). In membranes prepared from left ventricles of the hypertensive rats (by method 1) Na+-K+-ATPase activity was decreased, Mg2+-ATPase activity was increased, and the sialic acid content and 5'-nucleotidase activity (two putative membrane markers) were unchanged relative to the control rats. The sensitivity of cardiac Na+-K+-ATPase to inhibition by ouabain was also unchanged. Na+-K+-ATPase activity was also decreased in the right ventricles (method 1) of these hypertensive rats, suggesting that this defect is probably not pressure related. In membranes prepared from the left ventricles of the hypertensive rats by method 2, Na+-K+-ATPase activity was again reduced, whereas the Mg2+-ATPase and 5'-nucleotidase activities were unchanged relative to the controls. These studies suggest that myocardial Na+-K+-ATPase activity is suppressed in rats with this low renin form of hypertension and the possible effect of this suppression on myocardial contractile activity is discussed.
 ...
PMID:Decreased myocardial Na+-K+-ATPase activity in one-kidney, one-clip hypertensive rats. 613 90

5'-Nucleotidase activity in the cerebrovascular system in stroke-prone spontaneously hypertensive rats was histochemically investigated. In the hypertensive rats, an enhancement of 5'-nucleotidase activity was observed already in the early stage of hypertension and the enzyme activity increased with advancing age. The enzyme activity appeared earlier and stronger in the larger arteries in the basal portion than the pial arteries in the convexity of the brain and arterioles in the brain parenchyma. The activity in the arterial walls proved to be particularly strong in the thickened parts showing cellular hyperplasia, mainly at the branching portions. The reaction products localized along the plasma membrane, and also in the cytoplasma in some parts where the activity was strong. Relationship between the increased 5'-nucleotidase activity and aging of the cells composing the cerebrovasculature resulted from an accelerated or repeated cell proliferation was discussed.
 ...
PMID:Histochemical study on 5'-nucleotidase in the cerebrovascular system in stroke-prone spontaneously hypertensive rats. 627 95


1 2 3 Next >>