Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The powerful local metabolic regulation adjusting coronary blood flow to myocardial oxygen consumption under normal conditions is beyond doubt. However, despite substantial experimental efforts the responsible mediators are still largely unknown. Adenosine, a purported mediator of local metabolic control of coronary blood flow, is probably only involved in transient flow adaptations, but not in steady-state coronary autoregulation. Even below the autoregulatory range a substantial vasodilator reserve persists. Recruitment of such vasodilator reserve results in improved regional myocardial blood flow and attenuated regional ischemic dysfunction. beta-adrenergic coronary dilation is of minor functional importance. alpha-adrenergic coronary constriction acts to attenuate increases in coronary blood flow during sympathetic activation under normal conditions, such that myocardial oxygen extraction increases to match the increased oxygen consumption. alpha-adrenergic coronary constriction remains operative in ischemic myocardium, thus precipitating or contributing to acute myocardial ischemia during sympathetic activation and exercise in experimental animals as well as in patients with stable angina. The vagal transmitter acetylcholine--upon exogenous intracoronary infusion--induces critical constriction of epicardial coronary arteries with endothelial dysfunction and atherosclerosis. However, a vagal initiation of coronary spasm or myocardial ischemia has not been documented so far. Similarly, peptide hormones/transmitters such as NPY, vasopressin, and angiotensin can induce myocardial ischemia upon exogenous administration. Their pathophysiological role in myocardial ischemia and reperfusion, however, remains to be established.
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PMID:Local and neurohumoral control of coronary blood flow. 839 71

Independently of phenomena related to rejection, atherosclerosis of the grafted heart or high blood pressure, there exists a qualitative and quantitative degradation of response to exercise in heart transplant recipients. Maximal oxygen consumption is generally reduced to 40 to 60% of normal levels. There are several interactive mechanisms. Paradoxically, the transplanted heart is a clear demonstration of the fact that several other elements are involved in the organisms response to exercise. Indeed, ventilation, exercise load, peripheral circulation, muscle metabolism and neurohormonal response also play a role. Vasoactivity of the peripheral arteries limits distribution and extraction of oxygen during exercise. Noradrenaline, renin, atrial natriuretic factor, vasopressin and endothelin levels are normal at rest, but an overreaction occurs during exercise. The percentage of type I (oxidative) fibres is reduced in muscles. Cyclosporine has also been shown to have a toxic effect on mitochondria in muscles. The deinnervated transplanted heart is thus called upon to work in coordination with peripheral elements which have also undergone alterations. Consequently, response to exercise cannot be significantly increased above the level reached before transplantation. Usually patients are not greatly hindered in their daily activities and rarely complain of breathlessness. Nevertheless, an improvement would be appreciated. A coherent physical rehabilitation programme can increase maximal oxygen consumption by 25 to 30% in these patients, essentially via improvement in peripheral anomalies. It is more difficult to modify cardiac response.
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PMID:[Exercise capacity after heart transplantation]. 854 31

Cellular calcium modulates enzyme activity, cell proliferation, and differentiation. In vascular smooth muscle cells (VSMC), calcium may contribute to increased vascular contractility and structural alterations in both hypertension and atherosclerosis. We investigated the role of calcium in angiotensin II (AII)-induced prostaglandin release and DNA synthesis in VSMC. Prostaglandin levels were determined by radioimmunoassay, and DNA synthesis was determined by the incorporation of [3H]thymidine. AII dose-dependently stimulated the release of prostaglandin E2 and prostaglandin I2, and this effect was synergistically enhanced by the Ca2+ ionophore A23187. Conversely, the AII response was inhibited by EGTA, a chelator of Ca2+ ions and by verapamil and nifedipine, two Ca2+ channel blockers or by incubation of the cells without exogenous Ca2+. TMB-8, an inhibitor of calcium mobilization, also strongly reduced angiotensin response. Similar results were obtained for angiotensin III (AIII) and vasopressin, two other agonists of prostaglandin production. AII- or serum-stimulated DNA synthesis was almost abolished by EGTA, whereas TMB-8, verapamil, and nifedipine had little or no effect. The production of prostaglandins triggered by angiotensins and vasopressin in VSMC is dependent on both intracellular and extracellular calcium, with calcium entering through L-type Ca2+ channels. Extracellular calcium is important for AII and serum mitogenic activity, but L-type Ca2+ channels do not appear to be implicated.
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PMID:Role of calcium in angiotensin II-induced prostaglandin release and DNA synthesis in rat vascular smooth muscle cells. 872 Apr 17

1. Cytomegalovirus (CMV) is a major pathogen in immunocompromised individuals and may participate in the pathogenesis of atherosclerosis in the general population. We evaluated whether CMV-infection alters the function of arterial smooth muscle. 2. Blood pressure (BP) and arterial reactivity were recorded in immunosuppressed rats that had been infected with CMV (10(5) plaque forming units i.p.). Furthermore, the reactivity of isolated arteries was compared between CMV-infected rats and rats injected with bacterial endotoxin (LPS). 3. Initially resting BP and heart rate (HR) were not modified in CMV-infected rats, but baroreflex control of HR was impaired. By the eighth day post-CMV, BP dropped precipitously and could no longer be raised by phenylephrine (PHE). 4. In mesenteric resistance arteries, isolated at this stage from CMV-infected rats, contractile responses to nerve stimulation, noradrenaline, PHE and 5-hydroxytryptamine (5-HT) were virtually absent while those to high potassium and vasopressin (AVP) were not modified. In aortae of CMV-infected rats, responses to 5-HT and AVP were impaired while those to PHE or potassium were hardly affected. Reduced contractile responses could not be restored by NG-nitro-L-arginine methyl ester (L-NAME). 5. Continuous treatment of CMV-infected rats with prazosin (0.1 mg kg-1 day-1) prevented blood pressure lowering and resistance artery changes. 6. Observations in arteries of LPS-treated rats (5-10 mg kg-1, i.p.) differed markedly from those in vessels of CMV-infected animals. The contractile reactivity of their mesenteric resistance arteries was not altered while in their aortae, responses to PHE, 5-HT and AVP were reduced. With the exception of the AVP responses, this was more pronounced in the presence of 1-arginine and reversed by L-NAME. 7. These findings indicate that CMV-infection results in a reduction of resistance artery reactivity and hypotonia. This seems not to involve cytokine-mediated induction of NO synthase in the vascular wall but may be due to alterations of excitation-contraction coupling in arterial smooth muscle in response to increased sympathetic nervous input.
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PMID:Impaired arterial reactivity following cytomegalovirus infection in the immunosuppressed rat. 890 36

The majority of cases of central diabetes insipidus are still pathogenetically unclear (idiopathic). Atherosclerotic cholesterol emboli might be partly responsible for some of these idiopathic cases. A 54-year-old woman with known aortic valve stenosis and a history of a transitory ischemic attack presented with sudden-onset polyuria and polydipsia of up to eight l/d, which had started acutely with headaches. She had been treated with lithium for 3 years because of cyclothymic depression. Plasma sodium was in the upper normal range (142-148 mmol/l). Hypertonic saline infusion during lithium therapy revealed a normal threshold of thirst and resetting of vasopressin secretion (osmotic threshold > 300 mosmol/l), whereas vasopressin reserve was normal. Lithium withdrawal led to an even greater delay of vasopressin release upon hypertonic saline infusion (> 310 mosmol/l). Pituitary function tests revealed a normal anterior pituitary function. MR imaging of the hypothalamo-hypophyseal region showed a normal hypothalamic region and a highly intensive neurohypophyseal signal in the T1-weighted image. The patient responded well to desmopressin. We suggest that in this rare case clinical symptoms as well as biochemical findings like impairment of AVP release might be related to a minor structural hypothalamic damage by a vascular lesion, caused, for example, by an atheromatous (cholesterol) embolism in the hypothalamic region responsible for integration of osmoreceptor function and AVP-secretion. The patient's atherosclerosis and aortic stenosis might be responsible for this event.
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PMID:Atherosclerosis, aortic stenosis and sudden onset central diabetes insipidus. 928 11

Parathyroid hormone-related protein (PTHrP) appears to play crucial roles in the cardiovascular system. Over the past few years it has become apparent that there is more than one receptor recognizing parathyroid hormone or PTHrP, or both, and that PTHrP is not only a potent vasodilator of vascular smooth muscle cell tone, but is also a regulator of vascular smooth muscle cell proliferation and a secretagogue of renin and vasopressin. Investigators in several laboratories have started to query whether PTHrP intervenes in vascular diseases such as hypertension, (re)stenosis-atherosclerosis and endotoxaemia.
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PMID:Parathyroid hormone-related peptide--a smooth muscle tone and proliferation regulatory protein. 944 59

The renin-angiotensin system (RAS) is one of the oldest known hormone systems. Its effector hormone, angiotensin (Ang) II, acts through 2 receptor subtypes, AT(1) and AT(2). Most physiologic effects of Ang II, including vasoconstriction, renal salt and water retention, aldosterone and vasopressin release, and sympathetic facilitation, are mediated by AT(1). Recent data, however, suggest that Ang II also contributes to cell proliferation, left ventricular hypertrophy, vascular media hypertrophy, neointima formation in atherosclerosis, and nephrosclerosis by stimulation of AT(1) receptors. AT(2) receptors are associated with antiproliferation, cell differentiation and development, tissue regeneration, and apoptosis. They also antagonize AT(1) receptor-mediated effects, which suggests that the ratio of angiotensin receptors expressed on a particular cell can determine the net effect of Ang II. Selective AT(1) receptor antagonists ("sartans") have been used to treat several million hypertensive patients worldwide. These agents offer a powerful therapeutic alternative to angiotensin-converting enzyme (ACE) inhibitors, which reduce the generation of Ang II. Conversely, AT(1) receptor antagonists block the RAS by acting on cellular angiotensin receptors and do not interfere with the breakdown of kinins. These medications inhibit the RAS more completely than do the ACE inhibitors because their action is independent of Ang II-generating pathways. At the same time, early, preliminary data suggest that AT(1) receptor antagonists offer target-organ protection similar to that provided by the ACE inhibitors. Because AT(2) receptors are left unopposed and Ang II levels are increased with AT(1) receptor antagonist treatment, it is important to understand the function of AT(2) to fully appreciate the mechanisms of action of AT(1) receptor antagonists, especially their potential for target-organ protection.
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PMID:Neurohormonal modulation in cardiovascular disease. 1061 81

Angiotensin II plays a central role in the regulation of systemic arterial pressure through its systemic synthesis via the renin-angiotensin-aldosterone cascade. It acts directly on vascular smooth muscle as a potent vasoconstrictor. In addition, it affects cardiac contractility and heart rate through its action on the sympathetic nervous system. Angiotensin II also alters renal sodium and water absorption through its ability to stimulate the zona glomerulosa cells of the adrenal cortex to synthesize and secrete aldosterone. Furthermore, it enhances thirst and stimulates the secretion of the antidiuretic hormone. Consequently, angiotensin II plays a critical role in both the acute and chronic regulation of blood pressure through its systemic endocrine regulation. A potent neurohormone that regulates systemic arterial pressure, angiotensin II also affects vascular structure and function via paracrine and autocrine effects of local tissue-based synthesis. This alternate pathway of angiotensin II production is catalyzed in tissues via enzymes such as cathepsin G, chymostatin-sensitive angiotensin II-generating enzyme, and chymase. Intratissue formation of angiotensin II plays a critical role in cardiovascular remodeling. Upregulation of these alternate pathways may occur through stretch, stress, and turbulence within the blood vessel. Similar processes within the myocardium and glomeruli of the kidney may also lead to restructuring in these target organs, with consequent organ dysfunction. Additionally, angiotensin II may increase receptor density and sensitivity for other factors that modulate growth of vascular smooth muscle, such as fibroblast growth factor, transforming growth factor beta-1, platelet-derived growth factor, and insulin-like growth factors. Atherosclerosis may also be related, in part, to excessive angiotensin II effect on the vessel wall, which causes smooth muscle cell growth and migration. It also activates macrophages and increases platelet aggregation. Angiotensin II stimulates plasminogen activator inhibitor 1 and directly causes endothelial dysfunction. Other postulated effects of angiotensin II on vascular structure that could promote atherogenesis include inhibition of apoptosis, increase in oxidative stress, promotion of leukocyte adhesion and migration, and stimulation of thrombosis. Inhibition of angiotensin II synthesis with an angiotensin-converting enzyme inhibitor has been demonstrated to be beneficial in modifying human disease progression. This is clearly apparent in clinical trials involving patients with diabetic nephropathy, postmyocardial infarction, or advanced degrees of systolic heart failure. Thus, angiotensin II is an excellent target for pharmacologic blockade. Not only does it play a pivotal role in both the acute and chronic regulation of systemic arterial pressure, but it also is an important modulator of cardiovascular structure and function and may be specifically involved in disease progression. Modification of angiotensin II effect may therefore serve a dual purpose. Not only will blood pressure reduction occur with less stretch, stress, and turbulence of the vascular wall, but there will also be less stimulation, either directly or indirectly, for restructuring and remodeling of the cardiovascular tree.
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PMID:The renin-angiotensin-aldosterone system: a specific target for hypertension management. 1061 73

The aim of the study was to investigate the effect of two various atherogenic stimuli (vasopressin-induced hypertension or hypercholesterolemia) on the collagen and glycosaminoglycan (GAG) content in the internal or external part of both thoracic and abdominal aorta, which are differently susceptible to atherosclerosis. Experimental rabbits were divided into four groups: controls, animals injected with physiological saline or vasopressin at the dose of 1 IU/kg from the 1 st to the 25 th day of experiment, respectively. The animals from group 4 were maintained on food, containing 0.25% cholesterol. Only in the vasopressin-treated group, the systolic blood pressure was elevated from 110 mmHg at the beginning, to 166 mmHg at the end of the study. After 14 weeks the aorta was dissected into internal and external parts. GAG fractions were separated and estimated as uronic acids. Collagen was evaluated as the hydroxyproline content in the tissue. Augmented total GAG and heparan sulphate (HS) level, plus no changes in the collagen content were seen in the internal part of the thoracic aorta in rabbits with hypercholesterolemia or hypertension. In the hypertensive animals, the changes were extended to the external part of the aorta and, additionally, comprised the elevation of the chondroitin-4 sulphate (C-4S) content. The two atherogenic stimuli increased the collagen level with no elevation of the GAG content in the abdominal aorta. A convergent effect of the injury, caused by hypertension or hypercholesterolemia on the collagen, total GAG and HS content was shown in the respective parts of the rabbit aortas. The common GAG, increased in the thoracic aorta, stand for the HS, in both hypertensive and hypercholesterolemic rabbits. As the sensitivity to atherosclerosis development in different segments of the aorta varies, they express various responses of the connective tissue matrix to injuries, caused by hypertension or hypercholesterolemia.
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PMID:Response of aorta connective tissue matrix to injury caused by vassopressin-induced hypertension or hypercholesterolemia. 1101 71

Endothelin-1 (ET-1) is a pleiotropic hormone produced primarily by the endothelium. Synthesis of ET-1 is stimulated by the major signals of cardiovascular stress, such as vasoactive agents (angiotensin II, norepinephrine, vasopressin, and bradykinin), cytokines (e.g., tumor necrosis factor alpha and transforming growth factor beta), and other factors, including thrombin and mechanical stress. ET-1 induces vasoconstriction, is proinflammatory, promotes fibrosis, and has mitogenic potential, important factors in the regulation of vascular tone, arterial remodeling, and vascular injury. These effects are mediated via two receptor types, ETA and ETB. The role ET-1 plays in normal cardiovascular homeostasis and in mild essential hypertension in humans is unclear. However, certain groups of essential hypertensive patients may have ET-1-dependent hypertension, including blacks (subjects of African descent), salt-sensitive hypertensives, patients with low renin hypertension, and those with obesity and insulin resistance. ET-1 has also been implicated in severe hypertension, heart failure, atherosclerosis, and pulmonary hypertension. In all of these conditions, plasma immunoreactive ET levels are elevated and tissue ET-1 expression is increased. Accordingly, it is becoming increasingly apparent that ET-1 plays an important role in cardiovascular disease and in some forms of hypertension in humans. Data from clinical trials using combined ETA-ETB receptor blockers have already demonstrated significant blood-pressure-lowering effects. Thus, targeting the endothelin system may have important therapeutic potential in the treatment of hypertension, particularly by contributing to the prevention of target organ damage and the management of cardiovascular disease.
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PMID:Role of endothelin in human hypertension. 1283 65


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