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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of cardiac output was determined by 15 micron radioactive microspheres in all the major organs of spontaneous, DOCA/NaCl and one kidney Goldblatt hypertensive rats and compared to normotensive Wistar rats. Although there were alterations in cardiac output distribution which were characteristic of each model of hypertension significant changes were common to all three were an increased distribution to skeletal muscle with decreases to the lungs, spleen and hepatosplanchnic tissues. The results suggest that alterations in peripheral resistance induced by hypertension are of unequal importance in the different vascular beds with certain vascular resistance changes occurring irrespective of the origin of the hypertension.
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PMID:Distribution of cardiac output in different models of hypertension in the conscious rat. 57 Nov 18

High blood pressure in DOCA-saline treated uninephrectomised rats is prevented or even reversed by tyrosine, tyramine or by treatments which - based on circumstantial evidence - might increase local brain tyramine concentration.
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PMID:d-Tyrosine prevents hypertension in DOCA-saline treated uninephrectomised rats. 57 36

The hypotensive and diuretic activities of a new diuretic, 1,4-dimorpholino-7-phenylpyrido[3,4-d] pyridazine (DS-511), were compared with those of hydrochlorothiazide (HC) in DOCA, renal and spontaneously hypertensive rats. The results obtained were: 1. During the developing stage of DOCA-hypertension the daily treatment of rats with DS-511 and HC showed significant hypotensive action. During this period the diuretic activity of both agents was clear. 2. During the equilibrium stage of DOCA-hypertension the hypotensive action of DS-511 was indistinct despite its diuretic activity. The hypotensive and diuretic action of HC was not clear. 3. In renal-hypertensive rats the daily treatment of DS-511 and HC caused significant, but weaker hypotension than that in the developing stage of DOCA-hypertension. In these animals the diuretic activity of both agents was clear. 4. In spontaneously hypertensive rats the daily treatment with DS-511 and HC exhibited a similar hypotensive and diuretic action. 5. In all three kinds of hypertensive rats the diuretic activity of DS-511 was similar to that of HC in the excretion of urine and sodium, but the former was less kaliuretic than the latter.
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PMID:Comparison of the hypotensive and diuretic effects of 1,4-dimorpholino-7-phenylpyrido[3,4]pyridazine (DS-511) and hydrochlorothiazide in Doca, renal and spontaneously hypertensive rats. 57 34

The release of prostaglandin-like (PG-like) material by aorta strips of normotensive and hypertensive rats has been studied in vitro. When incubated in an oxygenated Krebs solution kept at 37 degrees C, aorta strips removed from 8- and 12-week-old spontaneously hypertensive (SH) rats generate 1.2-2.5 times more PG-like material than aorta strips from age-matched normotensive Wistar (NW) rats. The overproduction of PG-like material by aorta strips of SH rats did not precede the development of hypertension in SH rats. Aorta strips derived from renal and DOCA-salt hypertensive rats produced 1.5-3 times more PG-like material than aorta strips from NW rats. The production of PG-like material by aorta strips of renal and DOCA-salt hypertensive rats was largely reduced when hypertension was interrupted in these animals, thus suggesting that the alteration taking place in the arteries of hypertensive rats (namely increased production of PGs) during the development of hypertension was reversible. The production of PG-like material by aorta strips of hypertensive rats was inhibited by indomethacin. Analysis of the PG-like material by bioassays and thin-layer chromatography suggests the presence of PGE2 and PGE1. The possible involvement of these PGs in the pathogenesis of hypertension in rats is discussed.
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PMID:The role of prostaglandins in hypertension. I. The release of prostaglandins by aorta strips of renal, DOCA-salt, and spontaneously hypertensive rats. 59 81

The results of this study demonstrate that the spontaneously hypertensive rat is sensitive to salt excess. The hypertensinogenic effect of salt was mediated through elevation of peripheral vascular resistance. The addition of DOCA aggravated the hypertension, mainly be elevating the cardiac output without appreciably decreasing peripheral vascular resistance. SHR'S EXPOSED TO 1% NaCl consumed more fluids and excreted more sodium and urine than control rats. Those exposed to 1% NaCl and DOCA had higher fluid consumptions and excreted more sodium than the other two groups. These effects of sodium in a neurogenic strain of hypertensive rats suggest a possible interplay between the neurogenic and salt-dependent components in the development and maintenance of hypertension. They also suggest that SHRs, like other hypertensive rat models, are salt sensitive.
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PMID:Hemodynamic changes induced by prolonged NaCl and DOCA administration in spontaneously hypertensive rats. 65 61

Three types of renal hypertension in the rat have been compared with respect to blood pressure increase, activity of the RAS, and secretion of aldosterone and corticosterone: type I - unilateral stenosis of the renal artery in the presence of an intact contralateral kidney; type II - unilateral stenosis of the renal artery after contralateral nephrectomy; type III - bilateral stenosis of the renal arteries. Blood pressure rose more rapidly and reached higher values in type II and type III hypertension than in type I hypertension. In the latter group, the activity of the RAS was more stimulated than in types II and III. The marked stimulation of the RAS in type I hypertension is ascribed to the negative fluid and sodium balance, which is the consequence of a pressure-induced diuresis of the unclamped contralateral kidney. Suppression of the activity of the RAS by a 4-week pretreatment with DOC-TMA and saline or by the administration of DOCA and saline as from the induction of renal artery stenosis did not prevent the development of hypertension caused by the clamping of one renal artery (type I). In spontaneously hypertensive rats of the stroke-prone substrain, high dietary salt intake caused higher blood pressure values and a higher incidence of cerebral lesions than normal dietary salt intake. Low salt intake was followed by a marked stimulation of the RAS, but blood pressure rose only slightly and no symptoms of cerebrovascular lesions were observed. It is concluded that neither in hypertension induced by renal artery stenosis nor in spontaneously hypertensive rats, the RAS contributes significantly to the increase in blood pressure nor does it play a major part in the pathogenesis of vascular lesions. These seem to be related to the retention of sodium, which may be obtained by renal artery stenosis, by excessive salt intake, or by the administration of a mineralocorticoid and salt.
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PMID:What makes the renin-angiotensin system a pathogenic factor? 69 4

The sensitivity of two strains of rat to the hypertensinogenic action of DOC was studied. Hypertensive cardiovascular disease was evident within 3 weeks of implantation of DOC pellets in sensitized female rats of the Sprague-Dawley and Long-Evans strains. Cardiac and renal hypertrophy due to DOC treatment was evident in both strains of rat. The DOC treatment also resulted in a significant decrease in absolute adrenal weight. These results, which indicate that Long-Evans rats are not resistant to DOC-induced hypertension, contrast with previous reports by others. An explanation of the discrepancy may be the use of free DOC rather than DOC acetate in the present study.
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PMID:The occurrence of 11-deoxycorticosterone (DOC)-induced hypertension in the Long-Evans rat. 71 Mar 67

Young female unilaterally nephrectomized, salt-loaded, Sprague-Dawley rats were treated with 200 microgram or 1 mg 18-hydroxy-deoxycorticosterone-21-acetate (18-OH-DOCA) in oil daily, and a group of kidney-intact animals on a normal salt intake was given 2 mg/day. The hormone was not found to increase saline consumption, increase urinary potassium or kallikrein excretion, or depress serum renin activity or potassium concentration. Slight hypertension did develop at 3 weeks in salt-loaded rats on the lowest dose, but this was neither increased by higher dosage or longer treatment, nor reflected by increased heart or kidney weight. The effect of 40-mg pellet implantation of DOCA and 18-OH-DOCA was then compared in unilaterally nephrectomized, salt-loaded, female Fischer 344 rats. The former caused increased saline consumption, hypertension, hypokalemia, and heart and kidney enlargement, whereas 18-OH-DOCA did not. Thus, the hypertensogenic potency of 18-OH-DOCA is, at best, a reflection of its known, very weak, mineralocorticoid activity.
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PMID:Experimental hypertension and other responses to 18-hydroxy-deoxycorticosterone treatment in the rat. 74 64

The development of hypertension was studied in rats after neonatal sympathectomy by s.c. injection of 6-hydroxydopamine HCl. Three different types of hypertension were investigated: renal hypertension in the two-kidney Goldblatt model, steroid hypertension produced by deoxycorticosterone (DOCA) implantation and saline as drinking fluid, and genetic hypertension in the spontaneous hypertensive rat (SHR). Blood pressure was measured directly in conscious animals via the iliac artery. Mean blood pressure of conscious sympathectomized (SX) normotensive rats was not significantly different from that of normotensive controls. Renal hypertension reached the same level in controls and SX rats four weeks after application of a renal artery clip. DOCA-salt hypertension developed faster and to a higher level in SX rats than in control rats. The hypertension in SX DOCA-salt hypertensive rats was accompanied by a marked tachycardia. In contrast hypertension did not develop in SX SHR. Up to 12 months of age mean blood pressure was markedly lower than that of control SHR, but slightly higher than that of SX normotensive Wistar Kyoto rats. These differential effects of neonatal sympathectomy on the development of hypertension in the rat may point to differences in the pathophysiological mechanisms. It is concluded that an intact sympathetic nervous system is essential for the development of hypertension in SHR. In DOCA-salt hypertension the intact sympathetic nervous system appears to protect against a rapid rise in blood pressure.
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PMID:Differential development of renal, DOCA-salt, and spontaneous hypertension in the rat after neonatal sympathectomy. 75 48

Plasmorrhagia of the arterial wall of various organs in rats with ischemic renal, DOCA-saline, and genetic spontaneous hypertension was studied by the method of fluorescent antibodies according to Coombs with the use of pure antibodies to yamma-globudin of a rabbit. The most pronounced plasmorrhagia was observed in rats with DOCA-saline hypertension in the arterial vessels of the kidneys. In rats with genetic hypertension lesions of the heart vessels were noted.
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PMID:[Immunomorphological study of plasmorrhagia in experimental hypertension in rats]. 79 54


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