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1.
Dtsch Med Wochenschr ; 135(48): 2426-7, 2010 Dec.
Article in German | MEDLINE | ID: mdl-21108159

ABSTRACT

BACKGROUND AND OBJECTIVES: To provide a source of valid information to hypertensive patients, their families as well as the public a cardiovascular hotline (HKT) has been established by the German Hypertension Society in April 1992. Until the end of the year 2007 approx. 55.000 phone calls have been answered. The aim of this study was to assess the callers' support needs and the perception of the information received. DESIGN: Callers who had previously provided their contact data were called back later. From a total of 803 eligible persons 311 volunteered for a phone interview made up of ten questions concerning (1) the accessibility of the phone service, (2) the atmosphere of the conversation and (3) the adequacy of time for the phone conversation, (4) the suitability of the answers received, (5) life style changes initiated by the original phone call, (6) discussion with the attending physician about the phone conversation, (7) information about preventive measures against consequential damages of high blood pressure, (8) instructions about the prescribed medication as well as side effects, (9) improvement of the blood pressure after the call and (10) willingness to recommend to others a call at the cardiovascular hotline. The gender distribution of the participants in the interview revealed a sex ratio of 47 % females vs. 53 % males compared to 51 % females vs. 49 % males among all callers at the hotline in 2007. Members of both populations were quite evenly distributed over the federal states of Germany. Taken together, these findings suggest that the interview data are representative of the opinions of callers' at the cardiovascular hotline. CONCLUSION: The analysis of the results of the survey provide ample evidence that the cardiovascular hotline is well accepted by the callers and hence effective in conveying information about hypertension. This is particularly important in view of the ever increasing demand of such information by members of the rapidly ageing population in Germany.


Subject(s)
Hypertension/physiopathology , Patient Satisfaction , Antihypertensive Agents/adverse effects , Antihypertensive Agents/therapeutic use , Female , Germany , Hotlines , Humans , Hypertension/drug therapy , Hypertension/psychology , Life Style , Male , Perception , Social Support , Societies, Medical
2.
Dtsch Med Wochenschr ; 135(31-32): 1559-60, 2010 Aug.
Article in German | MEDLINE | ID: mdl-20665421

ABSTRACT

BACKGROUND AND OBJECTIVE: Despite the 1.5 million blood pressure monitors sold annually in Germany only 24 % of treated hypertensives reach the goal blood pressure below 140/90 mm Hg. This indicates that the care for hypertensive patients needs to be improved. PARTICIPANTS AND METHODS: In 1993 277 and in 2007 305 callers at the cardiovascular hotline were asked to participate in a short phone interview with identical questions in both years on self monitoring of blood pressure. Interview data from two points in time thirteen years apart permitted to look for changes in the answers. RESULTS AND DISCUSSION: Answers given at phone surveys in 1993 and 2007 revealed an increasing rate of self monitoring of blood pressure by patients. In contrast, only a limited interest of physicians was reported to introduce patients to blood pressure self monitoring. On the other hand, doctors were not consulted by patients before purchasing a blood pressure monitor. Based on the patients' self measurements drugs or their doses were changed only in one third of the cases. All this is probably caused by the limited time budget of the doctors.


Subject(s)
Antihypertensive Agents/therapeutic use , Blood Pressure Monitoring, Ambulatory/trends , Hypertension/drug therapy , Attitude of Health Personnel , Blood Pressure Monitoring, Ambulatory/statistics & numerical data , Dose-Response Relationship, Drug , Equipment Design/trends , Forecasting , Germany , Health Surveys , Hotlines , Hypertension/diagnosis , Hypertension/epidemiology , Patient Education as Topic/trends , Referral and Consultation/trends , Treatment Outcome
3.
J Phys Chem B ; 114(29): 9629-44, 2010 Jul 29.
Article in English | MEDLINE | ID: mdl-20604521

ABSTRACT

A set of nearly 100 crystallographic structures was analyzed using ab initio methods in order to verify the effect of the conformational variability of Watson-Crick guanine-cytosine and adenine-thymine base pairs on the intermolecular interaction energy and its components. Furthermore, for the representative structures, a potential energy scan of the structural parameters describing mutual orientation of the base pairs was carried out. The results were obtained using the hybrid variational-perturbational interaction energy decomposition scheme. The electron correlation effects were estimated by means of the second-order Møller-Plesset perturbation theory and coupled clusters with singles and doubles method adopting AUG-cc-pVDZ basis set. Moreover, the characteristics of hydrogen bonds in complexes, mimicking those appearing in B-DNA, were evaluated using topological analysis of the electron density. Although the first-order electrostatic energy is usually the largest stabilizing component, it is canceled out by the associated exchange repulsion in majority of the studied crystallographic structures. Therefore, the analyzed complexes of the nucleic acid bases appeared to be stabilized mainly by the delocalization component of the intermolecular interaction energy which, in terms of symmetry adapted perturbation theory, encompasses the second- and higher-order induction and exchange-induction terms. Furthermore, it was found that the dispersion contribution, albeit much smaller in terms of magnitude, is also a vital stabilizing factor. It was also revealed that the intermolecular interaction energy and its components are strongly influenced by four (out of six) structural parameters describing mutual orientation of bases in Watson-Crick pairs, namely shear, stagger, stretch, and opening. Finally, as a part of a model study, much of the effort was devoted to an extensive testing of the UBDB databank. It was shown that the databank quite successfully reproduces the electrostatic energy determined with the aid of ab initio methods.


Subject(s)
DNA/chemistry , Adenine/chemistry , Base Pairing , Cytosine/chemistry , Guanine/chemistry , Hydrogen Bonding , Static Electricity , Thermodynamics , Thymine/chemistry
4.
Dtsch Med Wochenschr ; 134(45): 2270-3, 2009 Nov.
Article in German | MEDLINE | ID: mdl-19876800

ABSTRACT

BACKGROUND AND OBJECTIVE: The cardiovascular hotline of the German Hypertension Society is a telephone information and support service which has been operated since 1992. This retrospective study was aimed at presenting a profile of the callers and the affected persons, a summary of the personal inquiries as well as significant changes over time based on three samples. PARTICIPANTS AND METHODS: A total of 55,000 phone calls were made from 1992 to 2007. Data of 20,195 inquiries representing three periods (1992/1993, 1999/2000, 2006/2007) were analysed. RESULTS: There were almost equal numbers of female and male callers. The same applied to the gender of the affected persons. In 80 % of the calls the concerned persons themselves asked for informations. In 12 % relatives called for a parent, occasionally for a child or a friend. In the three samples the average age of the affected persons increased from 56.4 to 63.7 years. In 1992/1993 calls mostly originated from areas of high population density in Germany but gradually from smaller towns, too. CONCLUSIONS: In the future more elderly persons will use the hotline and there will be more questions concerning topics of old age.


Subject(s)
Cardiovascular Diseases/therapy , Hotlines/statistics & numerical data , Hypertension/therapy , Information Services/organization & administration , Adult , Child , Female , Germany , Humans , Information Services/statistics & numerical data , Male , Middle Aged , Parent-Child Relations , Parents , Population Density , Societies, Medical , Time Factors
6.
Handb Exp Pharmacol ; (170): 407-42, 2005.
Article in English | MEDLINE | ID: mdl-16596809

ABSTRACT

The biological actions of angiotensin II (ANG), the most prominent hormone of the renin-angiotensin-aldosterone system (RAAS), may promote the development of atherosclerosis in many ways. ANG aggravates hypertension, metabolic syndrome, and endothelial dysfunction, and thereby constitutes a major risk factor for cardiovascular disease. The formation of atherosclerotic lesions involves local uptake, synthesis and oxidation of lipids, inflammation, as well as cellular migration and proliferation--mechanisms that may all be enhanced by ANG via its AT1 receptor. ANG may also increase the risk of acute thrombosis by destabilizing atherosclerotic plaques and enhancing the activity of thrombocytes and coagulation. After myocardial infarction, ANG promotes myocardial remodeling and fibrosis, and its many pathological mechanisms deteriorate the prognosis of these high-risk patients in particular. Therapeutically, inhibitors of the angiotensin I-converting enzyme (ACEI) and AT1 receptor blockers (ARB) are available to suppress the generation and cellular signaling of ANG, respectively. Despite major differences in the efficacy of ANG suppression and the modulation of other hormones and receptors, both classes of drugs are generally effective in attenuating numerous pathomechanisms of ANG in vitro, and in diminishing the development of atherosclerotic lesions and restenosis after angioplasty in various animal models. In clinical therapy, ACEI and ACE are well-tolerated antihypertensive drugs that also improve the prognosis of heart failure patients. After myocardial infarction and in stable coronary heart disease, ACEI have been shown to reduce mortality in a manner independent of hemodynamic alterations. However, there is little evidence that inhibitors of the RAAS may be effective against arterial restenosis, and a possible benefit of these substances compared to other antihypertensive drugs in the primary prevention of coronary heart disease in hypertensive patients is still a matter of debate, possibly depending on the specific substance and condition being investigated. As such, the general clinical efficacy of ACEI and ARB may be due to a positive influence on hemodynamic load, vascular function, myocardial remodeling, and neuro-humoral regulation, rather than to a direct attenuation of the atherosclerotic process. Further therapeutic advances may be achieved by identifying optimum drugs, patient populations, and treatment protocols.


Subject(s)
Angiotensin II Type 1 Receptor Blockers/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Atherosclerosis/drug therapy , Animals , Atherosclerosis/etiology , Atherosclerosis/prevention & control , Endothelium, Vascular/physiology , Humans , Peptidyl-Dipeptidase A/genetics , Renin-Angiotensin System/physiology , Thromboembolism/drug therapy
7.
Horm Metab Res ; 36(6): 370-5, 2004 Jun.
Article in English | MEDLINE | ID: mdl-15241726

ABSTRACT

The recently discovered neuropeptides orexin A and B regulate feeding behavior, neuroendocrine and autonomic functions, and sleep-wakefulness by central mechanisms. The expression of orexins and orexin receptors in various peripheral organs and the presence of orexin A in blood indicate the existence of a peripheral orexin system. In rat and human adrenal glands, both OX (1) and OX (2) receptor subtypes have been described with a predominant expression of OX (2) receptors in the adrenal cortex. In male rats, adrenocortical OX (2) receptors are much higher expressed than in female rats. Various experimental data demonstrate a stimulatory effect of orexins on the secretion of adrenocortical steroids, mainly on glucocorticoids. Some results also suggest the regulation of catecholamine synthesis and release by orexins. Whether the gender-dependent expression of adrenocortical OX (2) receptors has functional correlates awaits future clarification. As plasma orexin appears to rise during hunger and hypoglycemia, orexins may link adrenal functions with energy homeostasis.


Subject(s)
Adrenal Glands/physiology , Glucocorticoids/metabolism , Intracellular Signaling Peptides and Proteins/physiology , Neuropeptides/physiology , Receptors, Neuropeptide/metabolism , Catecholamines/biosynthesis , Feeding Behavior/physiology , Gene Expression Regulation/physiology , Humans , Hunger/physiology , Hypoglycemia/physiopathology , Neurosecretory Systems/physiology , Orexin Receptors , Orexins , Receptors, G-Protein-Coupled , Sex Factors , Sleep/physiology
9.
Dtsch Med Wochenschr ; 128(44): 2315-8, 2003 Oct 31.
Article in German | MEDLINE | ID: mdl-14593575

Subject(s)
Angiotensin II/antagonists & inhibitors , Angiotensin I/antagonists & inhibitors , Angiotensin Receptor Antagonists , Angiotensin-Converting Enzyme Inhibitors/administration & dosage , Angiotensin-Converting Enzyme Inhibitors/pharmacokinetics , Antihypertensive Agents/administration & dosage , Antihypertensive Agents/pharmacokinetics , Hypertension/drug therapy , Thiophenes , Acrylates/administration & dosage , Acrylates/pharmacokinetics , Acrylates/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Anti-Arrhythmia Agents/administration & dosage , Anti-Arrhythmia Agents/pharmacokinetics , Anti-Arrhythmia Agents/therapeutic use , Antihypertensive Agents/therapeutic use , Benzimidazoles/administration & dosage , Benzimidazoles/pharmacokinetics , Benzimidazoles/therapeutic use , Benzoates/administration & dosage , Benzoates/pharmacokinetics , Benzoates/therapeutic use , Biphenyl Compounds/administration & dosage , Biphenyl Compounds/pharmacokinetics , Biphenyl Compounds/therapeutic use , Clinical Trials as Topic , Germany , Humans , Imidazoles/administration & dosage , Imidazoles/pharmacokinetics , Imidazoles/therapeutic use , Irbesartan , Losartan/administration & dosage , Losartan/pharmacokinetics , Losartan/therapeutic use , Olmesartan Medoxomil , Placebos , Telmisartan , Tetrazoles/administration & dosage , Tetrazoles/pharmacokinetics , Tetrazoles/therapeutic use , Therapeutic Equivalency , Time Factors , Valine/administration & dosage , Valine/analogs & derivatives , Valine/pharmacokinetics , Valine/therapeutic use , Valsartan
11.
Clin Nephrol ; 58 Suppl 1: S2-6, 2002 Jul.
Article in English | MEDLINE | ID: mdl-12227721

ABSTRACT

Chronic pharmacotherapy of congestive heart failure deals with its special pathophysiology and acts on different sites of the cardiorenal axis. The standard-therapy consists of diuretics, ACE-inhibitors and beta-blockers and can be supplemented by cardiac glycosides, if heart failure worsens. Cardiac glycosides are also administered if tachycardic arrhythmias occur. Aldosterone-antagonists are combined with standard therapy in NYHA III - IV to counteract cardiac remodelling. AT1-antagonists are indicated when ACE-inhibitors are contraindicated or cannot be administered because of side-effects. Combination with ACE-inhibitors and AT1-antagonists may be of benefit for the patient since morbidity and hospitalization decrease.


Subject(s)
Heart Failure/drug therapy , Adrenergic beta-Antagonists/therapeutic use , Angiotensin I/antagonists & inhibitors , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Cardiac Glycosides/therapeutic use , Diuretics/therapeutic use , Humans , Mineralocorticoid Receptor Antagonists/therapeutic use , Vasodilator Agents/therapeutic use
12.
Can J Physiol Pharmacol ; 80(4): 258-63, 2002 Apr.
Article in English | MEDLINE | ID: mdl-12025958

ABSTRACT

The central hypertensive effects induced by bradykinin are known to be mediated via B2 receptors, which are present constitutively in the brain. B, receptors are rapidly upregulated during inflammation, hyperalgesia, and experimental diabetes. The hypothalamus plays an important role in the regulation of cardiovascular homeostasis, and all components of kallikrein-kinin system have been identified in this area. Therefore, we analyzed the mRNA expression of B1 and B2 receptors in the hypothalamus of spontaneously hypertensive rats (SHR) by RT-PCR. Male SHR were studied at three different ages corresponding to the three phases in the development of hypertension: (i) 3-4 (prehypertensive), (ii) 7-8 (onset of hypertension), and (iii) 12-13 weeks (established hypertension) after birth, and compared with age-matched Wistar-Kyoto (WKY) rats. At all ages tested, B2 receptor mRNA levels in the hypothalamus of SHR were higher than age-matched WKY rats (p < 0.001). However, the B1 receptor mRNA levels were higher at the established phase of hypertension only. We conclude that B1 and B2 receptor mRNA are differentially expressed in the hypothalamus of SHR and may play different roles in the pathogenesis of hypertension: upregulation of B2 receptor mRNA from early age may participate in the pathogenesis of hypertension, whereas an upregulation of B1 receptor mRNA in the established phase of hypertension may reflect an epiphenomenon in essential hypertension.


Subject(s)
Hypothalamus/metabolism , RNA, Messenger/biosynthesis , Receptors, Bradykinin/biosynthesis , Age Factors , Animals , Gene Expression Regulation/physiology , Male , Rats , Rats, Inbred SHR , Rats, Inbred WKY , Receptor, Bradykinin B1 , Receptor, Bradykinin B2
13.
MMW Fortschr Med ; 144(1-2): 50-4, 2002 Jan 17.
Article in German | MEDLINE | ID: mdl-11847884

ABSTRACT

As exemplified by the two classes of substance beta blockers and ACE inhibitors, the question is considered as to when new developments within a drug family can be termed innovations and when they must be seen purely as plagiarisms ("me-too" preparations). It is noted that in principle no innovations are to be expected from generics, since these substances are are not the subject of specific research. Although large-scale clinical studies in recent years have identified a new indication--cardiac insufficiency--for the beta blockers metoprolol, bisoprolol and carvedilol, this must not be considered an innovation in the sense of a new development. The translatability of the study results to uninvestigated substances is uncertain. In contrast to the beta blockers, the indications for the ACE inhibitors have long been known, but again, the new generic preparations that have come onto the market are not innovations.


Subject(s)
Adrenergic beta-Antagonists/therapeutic use , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Therapeutic Equivalency , Adrenergic beta-Antagonists/adverse effects , Adrenergic beta-Antagonists/pharmacokinetics , Angiotensin-Converting Enzyme Inhibitors/adverse effects , Angiotensin-Converting Enzyme Inhibitors/pharmacokinetics , Contraindications , Heart Failure/blood , Heart Failure/drug therapy , Humans , Treatment Outcome
14.
Am J Cardiol ; 88(12): 1351-7, 2001 Dec 15.
Article in English | MEDLINE | ID: mdl-11741551

ABSTRACT

Bradykinin accumulation is a potent cardioprotective mechanism underlying angiotensin-converting enzyme (ACE) inhibition in ischemia and/or reperfusion injury. There is, however, concern about treatment with ACE inhibitors in the very early phase of acute myocardial infarction (AMI) due to adverse systemic hemodynamic effects. We tested the hypothesis that cardiac bradykinin metabolism can be influenced by very low doses of intracoronary ACE inhibitors without harmful systemic effects in patients with AMI. Twenty-two patients with AMI in Killip classes II to III who underwent primary percutaneous transluminal coronary angiography (PTCA) were randomized to intracoronary enalaprilat (50 microg) or saline, given immediately after reopening of the infarct-related artery. Hemodynamics and electrocardiograms were monitored continuously and samples for determination of ACE activity, angiotensin II, bradykinin, kininogen, and cardiac marker proteins were collected from pulmonary arterial and central venous blood. Enalaprilat had no adverse effects on systemic hemodynamics, but rather stabilized arterial pressure and cardiac rhythm during reperfusion. Enalaprilat induced a 70% reduction of ACE activity and a significant increase of bradykinin in pulmonary arterial blood. Angiotensin II was not significantly affected by enalaprilat either in pulmonary arterial or in central venous blood. Myoglobin release was lower and the duration of reperfusion arrhythmias was significantly reduced in the enalaprilat group (p <0.05). Thus, in this pilot study, intracoronary enalaprilat infusion in the infarct-related artery is feasible in the setting of primary angioplasty and is safe and well tolerated. Effective cardiac ACE inhibition can be achieved by low-dose intracoronary enalaprilat, which primarily causes a potentiation of bradykinin.


Subject(s)
Angioplasty, Balloon, Coronary , Angiotensin-Converting Enzyme Inhibitors/therapeutic use , Enalaprilat/administration & dosage , Myocardial Infarction/drug therapy , Animals , Bradykinin/metabolism , Drug Synergism , Electrocardiography , Hemodynamics , Humans , Infusions, Intravenous , Pilot Projects , Rats , Ventricular Function, Left
15.
Clin Pharmacol Ther ; 70(4): 362-9, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11673752

ABSTRACT

OBJECTIVE: Reduced awareness of hypoglycemic symptoms and compromised hormonal counterregulation increase the risk of severe hypoglycemia in people with diabetes mellitus. Up to the present, angiotensin 1 receptor blockers, which play an important role in controlling diabetic complications, have not been known to increase the risk of hypoglycemia. Nevertheless, we observed 3 cases of diabetic patients complaining of reduced awareness of hypoglycemic symptoms while they were under treatment with losartan in our outpatients clinic. We therefore investigated the effects of losartan on symptomatic and hormonal responses to hypoglycemia in humans. RESEARCH DESIGN AND METHODS: We carried out a randomized, double-blind, crossover study including 16 healthy men. The subjects received losartan 50 mg/d versus placebo. Treatment periods lasted for 7 days and were followed by a stepwise hypoglycemic clamp session (4.5 to 3.8 to 3.1 to 2.4 mmol/L) with measurement of counterregulatory hormones (epinephrine, norepinephrine, adrenocorticotropin, cortisol, glucagon), symptoms, and hemodynamic parameters (blood pressure, heart rate). RESULTS: Losartan attenuated the hypoglycemia-induced rise in plasma epinephrine (6480 +/- 490 pmol/L versus placebo 8970 +/- 790 pmol/L; P <.001) and the rise in plasma adrenocorticotropin (21 +/- 2 pmol/L versus 26 +/- 3 pmol/L; P <.01). Losartan also reduced symptom scores during hypoglycemia (P <.05). CONCLUSION: We conclude that short-term treatment with losartan slightly attenuates symptomatic and hormonal responses to hypoglycemia. At present, for patients who are unaware of hypoglycemia and who require antihypertensive or nephroprotective treatment, we would recommend caution concerning treatment with losartan.


Subject(s)
Angiotensin Receptor Antagonists , Antihypertensive Agents/pharmacology , Glucose Clamp Technique , Hypoglycemia/physiopathology , Losartan/pharmacology , Adrenocorticotropic Hormone/blood , Adult , Contraindications , Cross-Over Studies , Double-Blind Method , Epinephrine/blood , Glucagon/blood , Hemodynamics/drug effects , Humans , Hydrocortisone/blood , Hypoglycemia/blood , Hypoglycemia/etiology , Male , Norepinephrine/blood , Receptor, Angiotensin, Type 1 , Renin-Angiotensin System/drug effects
16.
J Hypertens ; 19(10): 1827-33, 2001 Oct.
Article in English | MEDLINE | ID: mdl-11593103

ABSTRACT

OBJECTIVES: It has been shown that a diminished sympathetic activity contributes to the hypotensive and cardioprotective actions of angiotensin converting enzyme (ACE) inhibitors (ACEI). Besides an inhibition of central sympathetic tone and peripheral noradrenaline release, we hypothesized that the interactions of ACEI with the sympathetic system may include a modulation of neuronal catecholamine uptake by peripheral nerves. DESIGN: We investigated the influence of fosinopril on noradrenergic uptake into cardiac neurones in vitro and in vivo in acute and chronic models. METHODS AND RESULTS: Acute administration of fosinoprilat to isolated perfused rat hearts increased the extraction of [3H]-noradrenaline from the perfusate by 39%. Treatment (14 days) of spontaneously hypertensive rats (SHR) with fosinopril (20 mg/kg per day) enhanced the cardiac uptake of i.v. administered [3H]-noradrenaline by 28%. The endogenous left ventricular content of noradrenaline was increased by 49% after an antihypertensive treatment of SHR with fosinopril (20 mg/kg per day). Identical increases in cardiac noradrenaline stores (53%) were observed in SHR treated with a blood pressure ineffective dose of fosinopril (0.2 mg/kg per day). The myocardial content of adrenaline was increased in parallel to noradrenaline after both dose regimes. CONCLUSIONS: It is concluded that ACEI increases neuronal uptake of catecholamines in SHR in a blood pressure-independent manner. This effect occurs acutely and is independent of central sympathetic activity. Therefore, we hypothesize that ACEI modulate the activity of the cardiac noradrenaline transporter by direct activation. The improved uptake of noradrenaline may contribute to the antihypertensive and cardioprotective effects of ACEI.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/pharmacology , Fosinopril/analogs & derivatives , Fosinopril/pharmacology , Heart Conduction System/metabolism , Neurons/metabolism , Norepinephrine/pharmacokinetics , Rats, Inbred SHR/metabolism , Animals , Dose-Response Relationship, Drug , Heart Ventricles , In Vitro Techniques , Male , Myocardium/metabolism , Rats , Time Factors
17.
Br J Pharmacol ; 134(2): 370-4, 2001 Sep.
Article in English | MEDLINE | ID: mdl-11564655

ABSTRACT

1. Inhibitors of the angiotensin converting enzyme (ACE) have been shown to exert their cardioprotective actions through a kinin-dependent mechanism. ACE is not the only kinin degrading enzyme in the rat heart. 2. Since aminopeptidase P (APP) has been shown to participate in myocardial kinin metabolism to the same extent as ACE, the aims of the present study were to investigate whether (a) inhibition of APP leads to a reduction of myocardial infarct size in a rat model of acute ischaemia and reperfusion, (b) reduction of infarct size is mediated by bradykinin, and (c) a combination of APP and ACE inhibition leads to a more pronounced effect than APP inhibition alone. 3. Pentobarbital-anaesthetized rats were subjected to 30 min left coronary artery occlusion followed by 3 h reperfusion. The APP inhibitor apstatin, the ACE-inhibitor ramiprilat, or their combination were administered 5 min before ischaemia. Rats receiving HOE140, a specific B(2) receptor antagonist, were pretreated 5 min prior to enzyme inhibitors. Myocardial infarct size (IS) was determined by tetrazolium staining and expressed as percentage of the area at risk (AAR). 4. IS/AAR% was significantly reduced in rats that received apstatin (18+/-2%), ramiprilat (18+/-3%), or apstatin plus ramiprilat (20+/-4%) as compared with those receiving saline (40+/-2%), HOE (43+/-3%) or apstatin plus HOE140 (49+/-4%). 5. Apstatin reduces IS in an in vivo model of acute myocardial ischaemia and reperfusion to the same extent than ramiprilat. Cardioprotection achieved by this selective inhibitor of APP is mediated by bradykinin. Combined inhibition of APP and ACE did not result in a more pronounced reduction of IS than APP-inhibition alone.


Subject(s)
Aminopeptidases/antagonists & inhibitors , Bradykinin/analogs & derivatives , Kinins/physiology , Myocardial Infarction/prevention & control , Peptides/pharmacology , Protease Inhibitors/pharmacology , Ramipril/analogs & derivatives , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Blood Pressure/drug effects , Bradykinin/pharmacology , Bradykinin Receptor Antagonists , Heart/drug effects , Heart/physiopathology , Heart Rate/drug effects , Hemodynamics/drug effects , Male , Myocardial Infarction/pathology , Myocardium/pathology , Ramipril/pharmacology , Rats , Rats, Wistar , Receptor, Bradykinin B2
18.
Hypertension ; 38(1): 142-6, 2001 Jul.
Article in English | MEDLINE | ID: mdl-11463775

ABSTRACT

The potentiation of kinin actions represents a cardioprotective property of ACE inhibitors. Although a clear contribution to this effect is related to the inhibition of bradykinin (BK) breakdown, the high efficacy of potentiation and the ability of ACE inhibitors to provoke a B(2)-receptor-mediated response even after receptor desensitization has also triggered hypotheses concerning additional mechanisms of kinin potentiation. The application of kinin analogues with enhanced metabolic stability for the demonstration of degradation-independent mechanisms of potentiation, however, has yielded inconsistent results. Therefore, the relation between the susceptibility of B(2)-agonists to ACE and the potentiation of their actions by ACE inhibitors was investigated with the use of minimally modified kinin derivatives that varied in their degree of ACE resistance. The B(2)-agonists BK, D-Arg-[Hyp(3)]-BK, [Hyp,(3) Tyr(Me)(8)]-BK, [DeltaPhe(5)]-BK, [D-NMF(7)]-BK, and [Phe(8)psi(CH(2)-NH)Arg(9)]-BK were tested for degradation by purified rabbit ACE and for their potency in contracting the endothelium-denuded rabbit jugular vein in the absence and presence of ramiprilat. Purified ACE degraded D-Arg-[Hyp(3)]-BK and [Hyp,(3) Tyr(Me)(8)]-BK at 81% and 71% of BK degradation activity, respectively, whereas other peptides were highly ([DeltaPhe(5)]-BK) or completely ([D-NMF(7)]-BK, [Phe(8)psi(CH(2)-NH)Arg(9)]-BK) resistant. The EC(50) of BK-induced venoconstriction (1.15+/-0.2 nmol/L) was reduced by a factor of 5.7 in the presence of ramiprilat. Likewise, D-Arg-[Hyp(3)]-BK and [Hyp,(3) Tyr(Me)(8)]-BK were both significantly potentiated by a factor of 4.4, whereas the activities of the other agonists were not affected. Ramiprilat exerted no influence on the maximum contraction induced by any of the agonists. It is concluded that the potentiation of kinin analogues during ACE inhibition correlates quantitatively with the susceptibility of each substance to degradation by ACE. As such, no evidence of degradation-independent potentiating actions of ACE inhibitors could be obtained.


Subject(s)
Angiotensin-Converting Enzyme Inhibitors/pharmacology , Jugular Veins/drug effects , Kinins/pharmacology , Ramipril/analogs & derivatives , Ramipril/pharmacology , Vasoconstriction/drug effects , Animals , Bradykinin/pharmacology , Dose-Response Relationship, Drug , Drug Synergism , In Vitro Techniques , Jugular Veins/physiology , Kinins/chemistry , Male , Peptidyl-Dipeptidase A/metabolism , Rabbits , Receptors, Bradykinin/metabolism
20.
Neuroreport ; 12(10): 2117-20, 2001 Jul 20.
Article in English | MEDLINE | ID: mdl-11447318

ABSTRACT

The expression of prepro-orexin (PPO) mRNA in the rat brain was investigated by in situ hybridization histochemistry. In the lateral and posterior hypothalamic areas, which are considered to produce exclusively PPO mRNA, we found high levels of PPO mRNA expressions. We also localized PPO mRNA hybridization signals at lower levels around the lateral ventricles, the third and fourth ventricle. Cellular analysis by emulsion autoradiography revealed the expression of PPO mRNA in the ependymal cell layer. Our results demonstrate that beside the lateral and posterior hypothalamus PPO mRNA is expressed in ependymal cells.


Subject(s)
Ependyma/cytology , Ependyma/metabolism , Gene Expression Regulation/physiology , Neuropeptides/biosynthesis , Neuropeptides/genetics , Protein Precursors/biosynthesis , Protein Precursors/genetics , Animals , Fourth Ventricle/cytology , Fourth Ventricle/metabolism , Hypothalamic Area, Lateral/cytology , Hypothalamic Area, Lateral/metabolism , Intracellular Signaling Peptides and Proteins , Lateral Ventricles/cytology , Lateral Ventricles/metabolism , Male , Molecular Sequence Data , Orexins , RNA, Messenger/metabolism , Rats , Rats, Wistar , Third Ventricle/cytology , Third Ventricle/metabolism
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