摘要:

SUMMARY1. These studies were conducted to determine whether preservation of the functional integrity of the membrane, Na+,K+‐stimulated ATPase is essential for the atrial natriuretic factor (r‐ANF‐8–33) to enhance guanosine 3′,5′‐monophosphate (cGMP) content in the rat aortic smooth muscle. In freshly dissected rat aortic tissues, levels of cGMP were estimated using radioimmunoassay.2. ANF (0.1 μmol/L in Krebs‐Henseleit media) produced significant elevation in cGMP levels in the aortic smooth muscle when compared with that incubated in the control media, whereas suppression of Na+‐pump with ouabain (1.0 mmol/L) and/or K+‐free media did not produce any significant changes in the basal cGMP level; these two experimental manoeuvres did not prevent enhancement of cGMP by ANF.3. Incubation of the tissues in the media containing ouabain plus vasoconstrictor concentrations of norepinephrine (0.3 μmol/L) also did not alter basal cGMP levels and did not prevent the ability of ANF to elevate cGMP.4. These studies demonstrate that the antagonism by ouabain, of vasorelaxant effects of ANF (as reported in the literature) are not due to the prevention of the ability of ANF to enhance cGMP levels in the arterial smooth muscle. It is proposed that such an antagonism may be related to the actions of ouabain and ANF on diverse, and perhaps independent, mechanisms which affect Ca2+‐fluxes a

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01613.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. DOCA and 9α‐fludrocortisone were given to mice on a high‐sodium diet for periods of up to 20 weeks, resulting in decreases in plasma renin concentration, renal renin concentration and renal renin mRNA with both treatments.2. Plasma renin concentration was suppressed prior to suppression of renin mRNA and renal renin levels, indicating that suppression of synthesis and secretion of renin occur separately.3. The decrease in renal renin concentration that occurred with DOCA was greater and more rapid than the decrease that occurred with 9α‐fludrocortisone, suggesting that DOCA caused intra‐renal breakdown of renin.4. When DOCA was given to mice on a low‐sodium diet, plasma renin concentration and renal renin concentration increased, indicating that the effects of DOCA on renin levels were dependent on dietary sodium.5. Renin secretion and synthesis appeared to be controlled by different mechanisms and sodium balance has an important effect on bot

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01614.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Animals and histology from two previous investigations were used to test the hypothesis that a similar elevation in blood pressure may result in a different sequence of pathological changes in different experimental models of hypertension, DOCA‐salt and aortic‐ligature hypertension.2. To assess differences in morphological parameters, individual animals in the two groups were paired (n= 12) for the same level of blood pressure at sacrifice.3. Vascular damage was significantly less in the DOCA‐salt group (P<0.01). Glomerular lesions however were more severe in the DOCA‐salt group. In rats with aortic‐ligature hypertension significantly fewer glomeruli had fibrinoid and/or crescents than in DOCA‐salt rats (P<0.001). There were fewer glomeruli with epithelial cell droplets (ECD) and fewer ECD per glomerulus in aortic‐ligature when compared with DOCA‐salt hypertension (P<0.001,P<0.001, respectively).4. This study highlights the significance of factors other than blood pressureper sein producing vessel and glomerular lesions in experiment

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01615.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Ambulatory ECG monitoring was undertaken in healthy cigarette smokers (33) and non‐smokers (20) of similar age (21–66 years).2. The frequency of ventricular premature complexes (VPC) was less in habitual smokers (P<0,05; Mann‐Whitney rank test) and an average of more than 1 VPC per hour occurred in a higher proportion of non‐smokers than smokers: eight of 20 (40%)vstwo of 33 (6%) (P<0.01; Chi‐squ

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01616.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The changes in plasma concentrations of immunoreactive vasopressin (iVP) and atrial natriuretic factor (iANF) in response to haemorrhage (10–30% blood volume) were measured in 10 anaesthetized rabbits before and after cardiac receptor denervation (vagal nerve section). Carotid sinus pressure was maintained constant (60 mmHg) to eliminate any changing input from carotid baroreceptors.2. Haemorrhage increased iVP before and after vagal nerve section indicating that withdrawal of input from aortic baroreceptors may have contributed to the increase in iVP.3. Section of the vagus nerves attenuated the iVP response to haemorrhage.4. There was no correlation between release of iVP and iANF.5. Haemorrhage decreased iAF before and after vagal nerve section. Section of the vagus nerves increased iANF. Plasma iANF was highly correlated with atrial pressure and mean arterial pressure suggesting iANF release was secondary to changes in cardiac haemodynamic

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01617.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. This study investigated the effect of progesterone, which, under certain circumstances, can antagonize both the mineralocorticoid and glucocorticoid activities of steroid hormones, on the development and maintenance of adrenocorticotrophic hormone (ACTH)‐induced hypertension in conscious sheep.2. Progesterone (500 mg/day) alone, for 5 days, had no effect on blood pressure, but increased urinary Na excretion by 38 ± 10 mmol/day (P<0.05) during the first 24 h.3. Infusion of ACTH (5 μg/kg per day), alone, for 3 days, increased mean arterial pressure by 21 ± 2 mmHg (P<0.001) associated with hypernatraemia, hypokalaemia, urinary Na retention, and increased fasting plasma glucose concentration.4. Progesterone (500 mg/day) concurrently with ACTH blocked the rise in mean arterial pressure and the mineralocorticoid (urinary Na retention) but not the glucocorticoid (increase in plasma glucose concentration) effects associated with ACTH administration.5. Progesterone (500 and 1000 mg/day) failed to reverse the hypertension and hypokalaemia in sheep pretreated for 3 days with ACTH.6. Thus, progesterone blocked the onset but did not affect established ACTH hypertension. The mechanism by which progesterone blocked the development of ACTH hypertension appears to be related to the ability of progesterone to block the essential mineralocorticoid component of the adrenocortical steroids involved in the development of ACTH hyperten

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01618.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. The effects of low or high sodium intake for 4 weeks on cardiac catecholamines and 3,4‐dihydroxyphenylethylene glycol (DHPG) levels were studied in adult female Wistar rats.2. Rats receiving the low sodium diet had significantly higher plasma renin activity than rats receiving the high sodium diet.3. Dopamine concentrations in both the right and left ventricle were significantly higher in the low salt compared with the high salt rats, but noradrenaline, adrenaline and DHPG levels did not differ significantly between the two groups.4. These data do not support previous reports that sodium restriction reduces cardiac noradrenaline release, but suggest that alterations in sodium intake may influence cardiac noradrenaline metabolis

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01619.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Streptozotocin diabetes was induced in Wistar‐Kyoto rats fed a 50% protein diet. Animals were randomized to receive either the ACE inhibitor ramipril, 1 mg/L in drinking water (n= 7), or no treatment (n= 7), and were studied for 6 months. Blood glucose, body weight and glomerular filtration rate (GFR) were measured at 0, 1, 4, 8 and 16 weeks of diabetes and urinary albumin excretion was measured every 8 weeks.2. In both groups, GFR increased significantly within 1 week of induction of diabetes (P<0.001) and thereafter remained stable. There was no difference in GFR between the treated and untreated groups.3. Urinary albumin excretion increased progressively in both groups throughout the study. Ramipril treatment reduced albuminuria by approximately 50% at weeks 16 and 24 (P<0.01).4. The amelioration of diabetic albuminuria by ACE inhibition, in the setting of high dietary protein intake, may have important implications for the treatment of human diabetic nephropath

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01620.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SUMMARY1. Renal cellophane wrapping to produce hypertension causes thickening of the capsule of the kidney. To determine whether this compresses the kidney, deep renal vein wedge pressure was measured as an estimate of tissue pressure in anaesthetized rabbits 1 month after cellophane wrapping (n= 5) or a sham operation (n= 3).2. Renal vein wedge pressure was 18.3 ± 2.0 mmHg in hypertensive rabbits and 8.4 ± 1.1 mmHg in the sham‐operated rabbits.3. Arterial pressure was raised or lowered with angiotensin II or glyceryl trinitrate, respectively. Arterial and wedge pressures were approximately linearly related and, at any given arterial pressure, wedge pressure was approximately 8 mmHg higher in the cellophane‐wrapped kidney than in the kidney of the sham‐operated group.4. These results, showing that renal wedge pressure is elevated in renal wrap rabbits, indicate that the kidneys are compressed, probably by the thickened renal capsule. This may explain the increased renal vascular resistance seen in this form of hyper

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01621.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Hypertension—The Next Decade. Verapamil in Focus.Edited by A. Fleckinstein and J. H. Laragh.Hazardous Chemicals Information Annual No. 2.Edited by N. Irving Sax.Modern Cardiovascular Physiology.By C. R. Honi

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1989.tb01622.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY