摘要:

SUMMARY1. Active and inactive renin were measured in individual juxtaglomerular apparatus (JGA) and in whole kidney homogenates.2. The morphology of the JGA was examined in microbiopsy glomerular specimens and in kidneys fixed by arterial perfusion.3. In rats on high and normal salt intake the total renin content of a single JGA was 14 (s.e.m. = 3) and 29 (s.e.m. = 4) ng AI/h, respectively. The amount of cystoplasm occupied by renin granules was 20% and 27%. Crystalline cores were seen in 1.5% and 7% of the granules, respectively.4. Increased delivery of NaCl to the macula densa did not alter total renin, but decreased inactive renin from 30% to 0, crystalline core‐containing cells from 33% to 14% and decreased the percentage of granules with crystalline cores from 12% to 2.2%.5. Increased sodium in the diet and increased delivery of NaCl to the macula densa decreased the proportion of renin present in the inactive form and decreased the proportion of crystalline cores.6. These coincidental alterations suggest that crystalline cores contain inactive renin and suggest that the delivery of sodium to the macula densa activates reni

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00346.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. In rat isolated caudal artery preparations, tetradecapeptide renin substrate enhanced the responses to sympathetic nerve stimulation (0.5 Hz, 10 s).2. In guinea‐pig isolated atria, previously incubated in3H‐noradrenaline, tetradecapeptide renin substrate enhanced the stimulation‐induced efflux of radioactivity.3. The facilitation of noradrenergic transmission in rat caudal arteries and guinea‐pig atria was blocked by the angiotensin II receptor antagonist saralasin, but was not altered by converting enzyme inhibitors.4. In the pithed rat tetradecapeptide renin substrate increased blood pressure and this effect was reduced by the converting enzyme inhibitor, ca

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00347.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. In shrinking‐drop micropuncture studies in anaesthetized rats proximal tubular fluid reabsorption (Jva) decreased by 36% following intravenous infusion of enalapril. In a separate group of rats enalapril reduced fractional lithium clearance indicating decreased proximal fluid reabsorption.2. Following enalapril, GFR rose by 46% but absolute proximal reabsorption rose by 22% indicating 48% effectiveness of proximal glomerulo‐tubular balance (GTB). Since renal blood flow and glomerular filtration rate (GFR) increased in parallel and arterial pressure fell, fluid uptake and proximal GTB were unlikely to have been decreased by peritubular physical forces.3. In anaesthetized rats proximal fluid reabsorption and proximal GTB are modulated by endogenous All through direct stimulation of proximal tubular transp

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00348.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Stress was induced by immobilizing the hind limbs of rats for 12 days and housing the rats in individual cages. Control rats were housed in groups without immobilization. Blood pressure and heart rate were measured through an indwelling carotid cannula.2. After 10 and 12 days of immobilization and isolation, the stressed rats had significantly higher blood pressures (ca. 10 mmHg) and higher cardiac adrenaline levels (ca. 90%). After adrenal medullectomy cardiac adrenaline levels were markedly reduced in both stressed and control rats. Furthermore, the stressing procedure did not cause a rise in blood pressure in adrenal‐medullectomized rats.3. Desipramine HCl (2 mg/kg per day), administered orally to block the neuronal uptake of adrenaline, prevented the elevation in blood pressures and cardiac adrenaline levels. Propranolol HCl (2.8 mg/kg per day), orally, also prevented the rise in blood pressure.4. The results are consistent with the hypothesis that activation of facilitatory prejunctional β‐adrenoceptors on sympathetic nerves by neuronally‐released adrenaline may be responsible for the raised blood pr

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00349.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The effect of cellophane wrap hypertension (WRAP) and hypercholesterolemia (1% cholesterol diet, CHOL) for 4 weeks was assessed on the endothelium‐dependent vasodilator response to acetylcholine in conscious rabbits after pharmacological autonomic blockade.2. Dose‐response curves for the hindlimb vascular resistance (ear artery pressure/lower aortic blood flow; Doppler flowmeter) and acetylcholine infusion (i.v.) doses were unaltered in sensitivity (ED50) for any of the treatment groups. The range and slope of the curves were significantly altered by WRAP, CHOL or WRAP plus CHOL for acetylcholine and adenosine infusions consistent with medial hypertrophy in resistance vessels and raised serum viscosity.3. The effect of intimai thickening on the response to endothelium derived relaxing factor (EDRF) was tested in dog carotid artery ring segmentsin vitro4 weeks after endothelium removal.4. The relaxation responses to acetylcholine (EDRF‐dependent) and adenosine or nitroglycerin were not significantly altered by the neo‐intima.5. Therefore the response to EDRF released by acetylcholine in resistance vessels was unaltered by hypertension, hypercholesterolemia or both together. Neo‐intimal thickening in response to initial endothelium loss does not appear to alter EDRF responses in the carot

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00350.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The prevalence of left ventricular hypertrophy (LVH) in human essential hypertension is uncertain. Echocardiography was used to calculate left ventriuclar wall thickness (WT), relative wall thickness (t/r) and left ventricular mass (LVM) in 52 normal subjects, 30 patients with borderline hypertension and 33 untreated patients with essential hypertension.2. In 52 normal subjects WT was independent of age, sex, BSA, BP or habitual physical activity, but LVM was significantly related to BSA and age.3. After correction of LVM for age and BSA, 88% of 33 patients with untreated essential hypertension had LVM greater than predicted which identified a larger proportion of hypertensives with LVH than previous studies suggest.4. Wall thickness measurement alone also indicated that about 80% of newly diagnosed hypertensives have LVH.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00351.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The vascular reactivity (slope and range) and location parameter (ED50) of dose‐response curves in the hindquarter vascular bed in conscious rabbits previously subjected to renal cellophane wrapping or sham operation were examined.2. The animals were instrumented with pulsed Doppler flow transducers and chronic indwelling aortic catheters for intra‐arterial drug infusion. The rabbits were ganglion‐blocked with mecamylamine before constructing full dose‐response curves to intra‐arterial infusions of methoxamine, noradrenaline, angiotensin II, acetylcholine, adenosine and serotonin.3. Curves relating dose to conductance were fitted to the experiments involving constrictors and curves relating dose to vascular resistance fitted to those involving dilator drugs. With both classes of drugs the reactivity was significantly higher in the hypertensive animals than in sham‐operated rabbits.4. There was no difference in sensitivity (ED50value) between the hypertensive and control animals for any agonist tested.5. The increased reactivity, but not sensitivity, could be entirely accounted for by the vascular amplifier action of medial hypertrophy in h

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00352.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. The influence of dietary sodium intake on plasma catecholamines was examined as part of a dietary intervention study in 21 prehypertensive school children.2. Diastolic blood pressure was significantly elevated in girls after 3 weeks on a high sodium diet compared with a low sodium diet. Plasma adrenaline levels were raised slightly by the high sodium intake but plasma noradrenaline was significantly reduced.3. Increases of plasma catecholamines in response to standing or cold stress were unaffected by changes in sodium intake.4. The results indicate that the pressor effect of dietary sodium in children is not attributable to increased sympathetic nerve activity.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00353.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Atrial natriuretic peptide (8‐33; ANP) caused a prolonged hypotensive response following intravenous injection in anaesthetized rats.2. This response was abolished by captopril treatment and restored by concomitant angiotensin II infusion.3. These results suggest that ANP exerts its hypotensive action in the anaesthetized rat by the antagonism of the vasoconstrictor action of endogenous angiotensin I

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00354.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

SUMMARY1. Forty‐four males with treated essential hypertension and a moderate‐to‐heavy alcohol intake participated in a randomized controlled crossover trial of the effects of varying alcohol intake on blood pressure control. Usual antihypertensive therapy was maintained unchanged throughout.2. Self‐reported alcohol consumption fell from 452 ml ethanol/week (s.e.m. = 29) during normal drinking habits to 64 ml/week (s.e.m. = 8) while drinking low alcohol content beer.3. Mean systolic and diastolic blood pressures were significantly lower during the last 2 weeks of reduced alcohol (supine 5.0 mmHg, s.e.m. = 1.4, and 3.0 mmHg, s.e.m. = 0.9, respectively; erect 5.9 mmHg, s.e.m. = 1.6, and 2.9 mmHg, s.e.m. = 1.0, respectively).4. Body weight was also lower (0.94 kg, s.e.m. = 0.25) at the conclusion of the low alcohol intake period.5. Regression analysis suggested that reduction in alcohol intake contributed independently to the fall in both systolic and diastolic blood pressure, while weight change contributed independently to the fall in systolic blood pressure alone.6. It was concluded that curtailing moderate to heavy alcohol intake leads to improved blood pressure control in treated essential hypertensiv

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1986.tb00355.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY