摘要:

SUMMARY1. To examine whether an angiotensin‐converting enzyme (ACE) inhibitor prevents left ventricular (LV) hypertrophy even in low‐renin hypertension, we studied the effect of the administration of perindopril on cardiac hypertrophy induced by partial renal ablation in hypertensive rats.2. Rats that had undergone partial nephrectomy were randomly divided into four groups that received the following as drinking water: Group A, tap water; Group B, 1% sodium chloride (NaCl); Group C, NaCl + perindopril 3 mg/ kg per day; and Group D, NaCl + perindopril 1 mg/ kg per day. Plasma renin activity (PRA), angiotensin‐II (AII) concentration and cardiac tissue AII were measured.3. Supplementation of NaCl following nephrectomy increased the blood pressure and cardiac weight compared with rats that had undergone nephrectomy alone (P<0.05). Treatment with perindopril (3 mg/kg per day) did not affect the blood pressure and plasma AII but inhibited the increase of cardiac weight (P<0.05). Left ventricular AII was decreased in cases of reduced renal mass hypertension, but was not changed by treatment with perindopril.4. These results demonstrate that perindopril may be able to prevent LV hypertrophy even in low‐renin hypertension, which was not mediated by a reduction of blood pressure or suppression of the circulating and cardiac renin‐angiotensin systems. Other mechanisms of ACE inhibitors may contribute to the cardioprotectiv

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01660.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. The effects of diphenylene iodonium (DPI), an inhibitor of reduced nicotinamide adenine dinucleotide phosphate‐dependent oxidases (which generate superoxide anions), were studied on nitric oxide (NO)‐mediated responses in isolated preparations of the rat aorta and anococcygeus muscle.2. In aortic rings, the endothelium‐dependent relaxant action of acetylcholine was reduced by DPI (0.3–10 μmol/L) in a concentration‐dependent manner and abolished by the NO synthase (NOS) inhibitor L‐nitro‐NG‐arginine methylester (l‐NAME; 100 μmol/L). Relaxations induced by sodium nitroprusside (SNP) or NO were not affected by DPI or l‐NAME.3. In anococcygeus muscles, DPI (0.3–10 μmol/ L) as well as l‐NAME (5–100 μmol/L) produced concentration‐dependent reductions of relaxations produced by nitrergic nerve stimulation. Relaxations induced by NO and SNP were not affected by either DPI or l‐NAME. l‐Arginine (1 mmol/L) prevented the reduction of nitrergic relaxations by l‐NAME but not by DPI.4. Contractions of anococcygeus muscles elicited by exogenous noradrenaline (1 μmol/ L) were not affected or were inhibited by DPI (0.3–10 μmol/L), but the contractions elicited by noradrenergic nerve stimulation were significantly enhanced by DPI and l‐NAME. When noradrenergic contractions had already been maximally enhanced by l‐NAME (100 μmol/L), DPI produced no further enhancement. l‐Arginine (1 mmol/L) prevented the enhancement of noradrenergic contractions by l‐NAME but not by DPI.5. The efflux of radioactivity induced by field stimulation from anococcygeus muscles previously incubated with [3H]‐noradrenaline was not affected by either DPI or l‐NAME.6. Superoxide dismutase (SOD, 100 U/mL) had no significant effects on noradrenergic contractions, nitrergic relaxations, relaxations induced by NO or the actions of DPI in the rat anococcygeus muscle.7. The results suggest that the effects of DPI in reducing the NO‐mediated relaxations produced by acetylcholine in rat aortic rings and stimulation of nitrergic nerves in the rat anococcygeus muscle are due to the inhibition of NOS in these tissues. The effects of DPI were not sensitive to l‐arginine, and thus the

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01661.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. This study investigated the uptake and release of phosphate from everted intestinal sacs of mice.2. When the activity of sodium‐potassium ATPase was altered (by changing the cationic concentrations in the medium by the addition of ouabain and the manipulation of metabolism by the use of selective inhibitors or stimulants), the release of phosphate appeared to be much more affected by the changes than the uptake of phosphate.3. A small sodium gradient allowed uptake to be maintained. The addition of ouabain in the presence of an attenuated gradient significantly reduced the uptake and release of phosphate. The inhibitory effect of ouabain on phosphate release was partly reversed by an increase in the potassium concentration in serosal fluid.4. These results indicate a role for sodium‐potassium ATPase in phosphate release from the intest

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01662.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. The circadian variations of blood pressure and pulse rate in essential hypertensives either with or without diabetes mellitus were studied.2. Diabetic patients with orthostatic hypotension showed an increase in variability of blood pressure and a decrease in that of pulse rate when assessed by coefficient of variation. Cosinor analysis showed no significant circadian rhythm in both blood pressure and pulse rate in these patients.3. There were no differences in the circadian variations of blood pressure and pulse rate between essential hypertensives with and without diabetes mellitus unless orthostatic hypotension was present.4. These results suggest that diabetes mellitusper sedoes not have any effects on the circadian variations of blood pressure and pulse rate in essential hypertensives unless autonomic neuropathy is present.

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01663.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. To clarify possible abnormalities in catecholamines in the medulla oblongata in relation to severe hypertension, the authors measured changes in catecholamine levels in the medulla oblongata of malignant stroke‐prone spontaneously hypertensive rats (M‐SHRSP). Effects of the adrenal medullae and peripheral nerves were ruled out by adrenal demedullation and chemical sym‐pathectomy.2. The level of norepinephrine in the medulla oblongata was significantly lower in untreated M‐SHRSP than in untreated WKY (control) rats at 10 weeks of age. Further, it was significantly lower in treated M‐SHRSP than in the treated WKY group at both 6 and 10 weeks of age. The level of epinephrine in 6 week old treated M‐SHRSP was significantly higher than that in age‐matched treated WKY, but no other differences were observed in terms of epinephrine content. There were no age‐ or treatment‐related differences in dopamine levels in the medulla oblongata.3. Since norepinephrine has an inhibitory effect on blood pressure elevation in the nucleus tractus solitarii (NTS) in the medulla oblongata, the suppression of negative feedback due to a decrease in the activity of inhibitory neurons in the medulla oblongata appears to be involved in the development and progression of severe hypert

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01664.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. In the present study, rats were treated with pertussis toxin (8.4 μg, i.v.) to determine whether pertussis toxin‐sensitive G‐proteins were linked to receptors that mediate effects in the cardiovascular system.2. In the pithed rat the pressor responses to the α‐adrenoceptor agonists noradrenaline and (to a lesser extent) methoxamine were attenuated by pertussis toxin treatment; the tachycardia produced by noradrenaline was unaffected. The pressor response to serotonin was also attenuated by pertussis toxin treatment. These observations are consistent with known effects of pertussis toxin on these receptors.3. The vasodepressor responses to the muscarinic receptor agonist carbachol and to adenosine were reduced by pertussis toxin, suggesting that these events may have been mediated by pertussis toxin‐sensitive G‐proteins. However, the depressor responses to the β2‐adrenoceptor agonist salbutamol and to the receptor‐independent vasodilator drugs sodium nitroprusside and hydralazine were also reduced by pertussis toxin. These latter effects suggest that caution must be used in interpreting the effects of pertussis toxin since the mechanism of action of these drugs as elucidatedin vitrois thought not to involve pertussis toxin‐se

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01665.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. Intramuscular (i.m.) administration of the neuroleptics chlorpromazine, haloperidol and spiperone at doses ranging from 0.1 to 0.4 mg/kg in male rabbits induced a dose‐dependent penile erection.2. The i.m. administration of the α1‐adrenoceptor antagonists prazosin and bunazosin (0.1–0.4 mg/kg), induced a dose‐dependent penile erection. However, that of the peripheral dopamine receptor antagonist domperidone (0.4–4.0 mg/kg) and the dopamine receptor agonist apomorphine (0.1–1.0 mg/kg) did not. Penile erection was not induced by i.m. injection of chlorpromazine in combination with intrapenile administration of the α1‐adrenoceptor agonist methoxamine.3. Penile erection was induced by the administration of chlorpromazine (0.25–1.00 mg/body) into the lateral cerebral ventricle. At a low dose, however, the administration of chlorpromazine into the lateral ventricle induced a less notable penile erection than that induced intramuscularly.4. Penile erection was induced by i.m. injection of the ganglionic blocker hexamethonium (5–20 mg/ kg). When chlorpromazine was given after pretreatment with hexamethonium, penile erection was more notable than that induced by either drug given alone.5. These results suggest that neuroleptics could act locally in the penile structure to cause penile erection by α1‐adrenoc

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01666.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. The authors investigated the effect of two extrahepatic cholestasis models (one by bile duct ligation and the other by choledocho‐jugular fistula) on the hepatic clearance of horseradish peroxidase in male Sprague‐Dawley rats divided into four groups.2. In groups A (n =5 rats) and B (n = 5), bile duct ligation was performed, while a choledocho‐jugular fistula was created in groups C (n =5) and D (n= 7). A 10 mg intravenous bolus of horseradish peroxidase was injected after 24 h (groups A and C), 48 h (groups B and D) or 1 h (Group E; five sham‐operated rats). Serum and bile samples were then serially collected for 2 h.3. In all groups, serum horseradish peroxidase levels increased soon after injection and then rapidly decreased, the curves being similar. Biliary excretion increased for 30 min and then slowly decreased. The highest horseradish peroxidase biliary concentrations and outputs were found in Group B followed by Group A; both groups had significantly higher levels than Group E. No difference was found between horseradish peroxidase biliary excretion of groups C and D and that of sham‐operated rats.4. When each group was considered separately, sampling times correlated with the corresponding ratios of bile/ plasma HRP. Significant differences were found between the relative slopes of groups A, B and E, but not between those of groups C, D and E.5. In conclusion, bile duct obstruction greatly affects the plasma‐bile transfer of fluid phase markers, such as horseradish peroxidase, while single retention, caused by choledocho‐jugular fistula, has no influence. The increased biliary hyperpressure related to the duration of cholestasis may account for the degree of horseradish peroxidase transfer which, in turn, probably depends on an enhanced paracel

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01667.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SUMMARY1. The participation of cholinergic and gamma amino butyric acid (GABA) neurotransmitter systems in the anti‐nociceptive effect of gossypin was investigated using pharmacological tools.2. Physostigmine potentiated its anti‐nociceptive response while atropine failed to modify it significantly.3. THIP (4,5,6,7‐tetra hydroisoxazolo (5,4‐C) pyridin‐3‐ol) and gossypin treatment produced an additive response while bicuculline attenuated the anti‐nociceptive response of gossypin. Similar observations were recorded for morphine.4. It is suggested that cholinergic and GABAergic systems play a role in gossypin‐induced a

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01668.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

ISSN:0305-1870    

DOI:10.1111/j.1440-1681.1993.tb01669.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY