Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.15.1 (ACE)
18,300 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Isoprenaline hydrochloride injected subcutaneously in rats given a choice test of 1.8% NaCl and water, first induced saline intake which started immediately and was almost concluded in 15 min, followed by a copious water intake. When either saline or water were given in a separate test, saline intake surpassed the water intake in the first 15 min.2. The delay of 15, 30 or 60 min after injection of isoprenaline, 100 mug/kg, before drinking was allowed, significantly reduced saline intake but did not modify the amount of water subsequently drunk.3. Isoprenaline caused a sudden drop in arterial blood pressure, the extent and duration depending on the dose. The time of maximum drop 3-4 min after injection coincided with the time the rat drank salt.4. Isoprenaline-induced saline drinking was significantly reduced after bilateral nephrectomy but water intake was unaffected.5. The beta-adrenoceptor blocking agent, propranolol, inhibited isoprenaline-induced NaCl and water intake, while the alpha-adrenoceptor antagonist phenoxybenzamine abolished isoprenaline-induced NaCl intake and enhanced water intake.6. Saralasin acetate (P-113), a competitive inhibitor of angiotensin II, given into the third brain ventricle, prevented the isoprenaline-induced NaCl and water intake as well as angiotensin II-induced drinking. The angiotensin converting enzyme inhibitor SQ-20881 reduced the isoprenaline-induced NaCl and water intake.7. In conclusion, hypotension might be a component of salt drinking evoked by isoprenaline although the dipsogenic action of beta-stimulation is mainly due to endogenous renin-angiotensin activation.
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PMID:Drinking behaviour in rats treated with isoprenaline, angiotensin II or angiotensin antagonists. 23 Nov

To examine the cellular mechanisms of contractile dysfunction in postinfarction heart failure, we studied the effects of beta-adrenergic receptor stimulation on contractile function and Ca2+i handling of noninfarcted papillary muscles from sham-operated (n = 17) and infarcted (n = 17) rats. Ca2+i transients measured with the bioluminescent protein aequorin and parameters of isometric contraction were recorded during graded isoproterenol stimulation. Developed tension and peak rate of tension rise were depressed (p less than 0.05) in muscles from infarcted rats at physiological and maximally stimulating [Ca2+]oS. The time to peak tension was prolonged in the muscles from the infarcted rats, corresponding with prolongation of the time to peak Ca2+i. In muscles from sham-operated rats, isoproterenol increased both the amplitude of the Ca2+i transient and the peak rate of tension rise. In contrast, the inotropic response to isoproterenol was severely blunted in the muscles from infarcted rats despite a large increase in the amplitude of the Ca2+i transient. Isoproterenol abbreviated the time course of the isometric twitch and the Ca2+i transient in both groups. These findings suggest that postinfarction heart failure may be related in part to decreased force-generating capacity of the myofilaments. Treatment with captopril for 5 weeks, beginning 1 week after infarction (n = 14), resulted in reduction of left ventricular filling pressures and partial normalization of myocardial contractility and Ca2+i handling. In addition, compared with muscles from untreated infarcted rats, muscles from the captopril-treated rats exhibited improved contractile responses to increasing [Ca2+]o or isoproterenol. The inotropic response to isoproterenol in muscles from all three groups of rats had a significant negative correlation (r = -0.64, p less than 0.0001) with left ventricular end-diastolic pressure measured in vivo. Thus, the defect in excitation-contraction coupling in rats with postinfarction heart failure may be partially normalized by chronic load reduction with an angiotensin converting enzyme inhibitor.
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PMID:Captopril enhances intracellular calcium handling and beta-adrenergic responsiveness of myocardium from rats with postinfarction failure. 132 96

The oxidative pentose phosphate pathway is poorly developed in the rat heart compared with other organs, since the activity of glucose-6-phosphate dehydrogenase (G-6-PDH), the first and rate-limiting enzyme of the oxidative pentose phosphate pathway, is low. As a consequence, the available pool of 5-phosphoribosyl-1-pyrophosphate and the rate of adenine nucleotide biosynthesis are limited. Isoproterenol, 24 hours after subcutaneous administration at 0.1, 1, and 25 mg/kg, stimulated the activity of G-6-PDH in whole hearts dose-dependently from 4.3 +/- 0.16 (control) to 6.6 +/- 0.35, 10.3 +/- 0.82, and 11.5 +/- 0.56 units/g protein, respectively. The activity of 6-phosphogluconate dehydrogenase, another of the enzymes in the oxidative pentose phosphate pathway, remained unchanged. G-6-PDH activity started to increase 12 hours after isoproterenol application, when the glycogenolytic and functional response was over, and reached a peak value between 24 and 48 hours. This stimulating effect was also demonstrated in cardiac myocytes that were isolated 28 hours after isoproterenol application. beta-receptor blockade with atenolol reduced the isoproterenol-induced increase in cardiac G-6-PDH activity by 90%. Cycloheximide, which inhibits translation, and actinomycin D, which interferes with transcription, attenuated it by 83% and 78%, respectively. These results indicate that cardiac beta-adrenergic receptors and enzyme protein synthesis are involved in this effect. Other beta-sympathomimetic agents such as dopamine, dobutamine, fenoterol, salbutamol, and terbutaline also stimulated myocardial G-6-PDH activity in a time- and dose-related manner. The calcium antagonist D 600 (gallopamil) reduced the isoproterenol-elicited stimulation by 65%, and verapamil blunted the fenoterol-induced increase by 50%. This suggests that Ca2+ ions also contribute to the stimulation of the cardiac oxidative pentose phosphate pathway.
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PMID:Beta-adrenergic agonists stimulate the oxidative pentose phosphate pathway in the rat heart. 197 8

The direct effects of a renin inhibitor, N-acetyl-pepstatin and five angiotensin converting enzyme inhibitors, captopril and the active diacid forms of enalapril, ramipril, cilazapril, and CS-622, on the vascular renin-angiotensin system were examined in isolated perfused rat mesenteric arteries. Vascular renin activity and angiotensin II (Ang II) released into the perfusate were determined. Infusion of N-acetyl-pepstatin (5 X 10(-8)-5 X 10(-6) M) suppressed vascular renin activity and Ang II release dose dependently. Isoproterenol (10(-6) M) induced a 135 +/- 30% increase in Ang II release from the basal value. N-Acetyl-pepstatin (5 X 10(-6) M) suppressed isoproterenol-induced Ang II release. Infusions of 5 X 10(-6) M captopril and the diacid forms of enalapril, ramipril, cilazapril, and CS-622 by themselves had little effect on Ang II release, but concomitant infusion of isoproterenol with these angiotensin converting enzyme inhibitors significantly decreased Ang II release (71 +/- 21%, 51 +/- 40%, 8 +/- 21%, 69 +/- 24%, and 44 +/- 29% increase, respectively, from the basal values). These results indicate that N-acetyl-pepstatin suppresses the vascular renin-angiotensin system. This effect may in part contribute to the hypotensive actions of renin inhibitors. Although angiotensin converting enzyme inhibitors also suppress locally generated Ang II, the mechanism and physiological significance still remain to be clarified.
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PMID:Renin inhibitor and converting enzyme inhibitors suppress vascular angiotensin II. 266 30

The aim of the study was to investigate beta adrenoceptor modulation of norepinephrine release from sympathetic nerves in rat isolated kidney. After preincubation with [3H]norepinephrine, the renal nerves were stimulated at 1 Hz. The stimulation induced (S-I) outflow of radioactivity was taken as an index of norepinephrine release. Isoproterenol (0.1 microM) enhanced the S-I outflow of radioactivity. This effect was abolished by the beta-2 adrenoceptor blocking drug ICI 118551 (0.1 microM) but unaltered by the beta-1 adrenoceptor blocking drug atenolol (0.3 microM). In the presence of a high concentration of the angiotensin converting enzyme inhibitor captopril (5 microM), isoproterenol failed to enhance the S-I outflow of radioactivity. However, a lower concentration of captopril (0.1 microM), which totally abolished the facilitatory effect of angiotensin I (0.1 microM) on the S-I outflow of radioactivity, failed to alter the facilitatory effect of isoproterenol. Angiotensin II (0.03 microM) enhanced markedly the S-I outflow of radioactivity and in the presence of the angiotensin II receptor blocking drug saralasin (0.1 microM) this facilitatory effect was reduced markedly. Saralasin did not alter the facilitatory effect of isoproterenol. These results suggest that stimulation of prejunctional beta-2 adrenoceptors on renal sympathetic nerve endings enhances norepinephrine release. This effect is independent of local angiotensin II production and does not involve activation of prejunctional angiotensin II receptors within the rat kidney. However, the inhibitory effect of a high concentration of captopril (5.0 microM) on beta-2 adrenoceptor-mediated facilitation of norepinephrine release remains to be clarified.
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PMID:Beta adrenoceptor facilitation of norepinephrine release is not dependent on local angiotensin II formation in the rat isolated kidney. 282 55

1. Isolated preparations of rat anococcygeus muscle were incubated with [3H]-noradrenaline and the efflux of radioactivity induced by stimulation of intramural sympathetic nerves was used as a measure of release of transmitter noradrenaline. Isometric contractile responses were also measured. 2. Angiotensin I (0.03 microM) and angiotensin II (0.03 microM) produced non-sustained contractile responses and enhanced the stimulation-induced (S-I) effluxes of radioactivity as well as the contractile responses to electrical stimulation. These effects were blocked by the angiotensin II receptor antagonist saralasin (0.03 microM), and the effect of angiotensin I, but not angiotensin II, was blocked by the angiotensin converting enzyme inhibitor captopril (0.1 microm). 3. The findings indicate that there are both pre- and postjunctional receptors for angiotensin II and that angiotensin I is converted to angiotensin II in the anococcygeus muscle preparation. 4. Isoprenaline (0.1 microM) slightly enhanced the S-I efflux of radioactivity, and produced a greater enhancement after neuronal uptake blockade with desipramine (0.03 microm) and alpha-adrenoceptor blockade with phentolamine (1 microM). 5. The facilitatory effect of isoprenaline on S-I efflux of radioactivity was abolished by propranolol (0.3 microM), but was not affected by low concentrations of saralasin (0.03 microM) or captopril (0.1 microM) which abolished the effect of angiotensin I. The findings suggest that isoprenaline acts directly on prejunctional beta-adrenoceptors to enhance S-I noradrenaline release, rather than indirectly by releasing angiotensin II from within the tissue. Higher concentrations of saralasin (0.1 microM) or captopril (5 microM) did block the facilitatory effect of isoprenaline. The significance of this finding is not clear.
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PMID:Facilitation of noradrenaline release from sympathetic nerves in rat anococcygeus muscle by activation of prejunctional beta-adrenoceptors and angiotensin receptors. 285 20

Low and high doses of angiotensin converting enzyme (ACE) inhibitors have been shown either to enhance or suppress, respectively, the water intake of rats induced by acute administration of isoproterenol. In order to assess the role and sites of action of angiotensin II (Ang II) in this dual action of ACE inhibitors, rats were administered either low or high doses of enalapril or captopril, followed by isoproterenol, and were sacrificed 1 h later for determination of Fos-like immunoreactivity (FLI) in brain. Isoproterenol induced strong FLI in the magnocellular paraventricular (PVN) and supraoptic (SON) nuclei, and moderate staining along the structures of the rostral wall of the lamina terminalis (LT). Low doses of ACE inhibitors either had no effect or slightly increased FLI along the LT following isoproterenol. Enalapril reduced FLI in some other regions, including the parvocellular PVN. In contrast, high doses of ACE inhibitors abolished FLI along the LT, and reduced FLI in the PVN and SON. Captopril, but not enalapril, induced some FLI in the LT, SON and PVN. The data are discussed in terms of access of ACE inhibitors to the brain, and interactions with structures involved in Ang-related water intake.
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PMID:Action of angiotensin converting enzyme inhibitors in rat brain: interaction with isoproterenol assessed by Fos immunocytochemistry. 798 96

This study aimed to determine the density of vascular beta-adrenergic receptors in cultured endothelial cells and to study the regulation of endothelial receptors after exposure to catecholamines and the ACE inhibitors, lisinopril and ramiprilat. Membranes from bovine aortic endothelial cells (BAEC) and bovine pulmonary artery endothelial cells (BPAEC) showed saturable binding of the radioligand [125I]iodocyanopindolol (ICYP). The beta-receptor density and binding affinity were comparable in both types of endothelial cells. Isoproterenol induced significant down-regulation of beta-receptors (-50%; P < 0.01). Incubation (24h) with the ACE inhibitors lisinopril 10(-5) M (+28.8%; P < 0.05) and ramiprilat 10(-5) M (+33.7%, P < 0.09) augmented the beta-receptor density in BAEC, but lower ACE inhibitor doses had no affect. Incubation with lisinopril 10(-5) M for 24 h resulted in significantly lower cAMP baseline levels, but did not affect cAMP concentrations after stimulation with isoproterenol. These results indicate that down-regulation of endothelial beta-receptors occurs during prolonged exposure to beta-stimulation, and that high concentrations of ACE inhibitors may affect the density of endothelial beta-receptors.
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PMID:Regulation of beta-adrenergic receptors on endothelial cells in culture. 829 71

A 21-year-old woman with hypertension confirmed on ambulatory blood pressure monitoring and unresponsive to beta-blockers, diltiazem and amiloride was found to have serum potassium, renin and aldosterone levels at or just below the lower end of normal. Urinary glucocorticoid metabolite analysis revealed high excretion of cortisol and androgen metabolites, with normal serum cortisol levels. This pattern suggests a partial glucocorticoid resistance syndrome; such patients are more responsive to ACE inhibitors and spironolactone.
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PMID:Increased urinary cortisol and androgen metabolites in a young female with hypertension: partial glucocorticoid resistance syndrome. 1089 20

To assess the possible contribution of the circulatory and cardiac renin-angiotensin system (RAS) to the cardiac hypertrophy induced by a beta-agonist, the present study evaluated the effects of isoproterenol, alone or combined with an angiotensin I-converting enzyme inhibitor or AT(1) receptor blocker, on plasma and LV renin activity, ANG I, and ANG II, as well as left ventricular (LV) and right ventricular (RV) weight. Male Wistar rats received isoproterenol by osmotic minipump subcutaneously and quinapril or losartan once daily by gavage. Plasma and LV ANGs were measured by radioimmunoassay after separation by HPLC. Isoproterenol alone decreased blood pressure, more markedly when combined with losartan or quinapril. Isoproterenol significantly increased LV and RV weight and total collagen. Neither losartan nor quinapril inhibited the increases in LV or RV weight. Losartan prevented the increase in RV collagen but enhanced the increase in LV collagen. Isoproterenol increased plasma renin, ANG I, and ANG II three- to fourfold. Isoproterenol combined with losartan or quinapril, caused marked further increases except for a significant decrease in plasma ANG II with quinapril. Isoproterenol alone did not increase LV ANG II and, combined with losartan or quinapril, actually decreased LV ANG II. These results indicate that isoproterenol-induced cardiac hypertrophy is associated with clear increases in plasma ANG II, but not in LV ANG II. Both losartan and quinapril lower LV ANG II below control levels, but do not prevent the isoproterenol-induced cardiac hypertrophy. These findings do not support a role for the circulatory or cardiac RAS in the cardiac trophic responses to beta-receptor stimulation.
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PMID:Isoproterenol-induced cardiac hypertrophy: role of circulatory versus cardiac renin-angiotensin system. 1170 6


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