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  • 1
    Electronic Resource
    Electronic Resource
    Transient Expression of NMDA Receptor Subunit NR2B in the Developing Rat Heart (2000)
    Oxford UK : Blackwell Science Ltd.
    Journal of neurochemistry 75 (2000), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: NMDA receptors represent a subtype of the ionotropicglutamate receptor family, comprising three classes of subunits (NR1, NR2A-D,NR3), which exhibit distinct patterns of regional and developmental expressionin the CNS. Recently, some NMDA receptor subunits have also been described inadult extraneuronal tissues and keratinocytes. However, their developmentalexpression patterns are currently unknown. With use of RT-PCR and western blotanalysis, the expression of NMDA receptor subunit NR2B was investigated in thedeveloping rat heart. NR2B mRNA and protein were detected in heart tissue ofrats from embryonic day 14 until postnatal day 21 but disappeared 10 weeksafter birth. In contrast, no NMDA receptor subunit NR1,α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptor subunitGluR2, or anchoring postsynaptic density protein-95 could be detected in ratheart at any developmental stage. Confocal microscopy of cultured cardiacmyocytes (CMs) from neonatal rats revealed distinct NR2B staining mainly ofintracellular structures. However, no functional NMDA receptor could bedetected on CMs by whole-cell recordings. In conclusion, high concentrationsof NR2B protein can be detected in early rat heart development, but itsfunction still remains elusive.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2000.0752472.x
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  • 2
    Electronic Resource
    Electronic Resource
    Focal modification of electrical conduction in the heart by viral gene transfer (2000)
    [s.l.] : Nature America Inc.
    Nature medicine 6 (2000), S. 1395-1398 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] Modern treatment of cardiac arrhythmias is limited to pharmacotherapy, radiofrequency ablation, or implantable devices. Antiarrhythmic medications suppress arrhythmias, but their systemic effects are often poorly tolerated and their proarrhythmic tendencies increase mortality. Radiofrequency ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/82214
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  • 3
    Electronic Resource
    Electronic Resource
    Isoprenaline-induced increase in the 40/41 kDa pertussis toxin substrates and functional consequences on contractile response in rat heart (1992)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 345 (1992), S. 44-50 
    Details
    ISSN: 1432-1912
    Keywords: Gi-protein ; Force of contraction ; β-Adrenoceptor ; Isoprenaline infusion ; Rat heart
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Chronic β-adrenoceptor stimulation leads to desensitization of the myocardial adenylyl cyclase signalling pathway which includes β-adrenoceptor downregulation and upregulation of Gi-protein α-subunits. However, these investigations have mainly been done in cellular preparations. In this study we report that isoprenaline infusion in vivo leads to an increase in myocardial Gia and present evidence for functional consequences of this increase. Rats were treated by a 4-day subcutaneous infusion with isoprenaline (2.4 mg/kg·d), propranolol (9.9 mg/kg·d) and triiodothyronine (T3, 0.5 mg/kg·d) for comparison. Isoprenaline treatment increased the pertussis toxin-sensitive amount of Gia by 22±6% and decreased β1- and β2-adrenoceptor density from 35±4 to 23±6 fmol/mg protein and 24±4 to 8±6 fmol/mg protein, respectively. Contraction experiments on electrically driven papillary muscles revealed that the negative inotropic potency of the M-cholinoceptor agonist carbachol in the presence of isoprenaline was increased as compared to control (mean EC50-values: 0.04 μmol/l vs. 0.28 μmol/l). All isoprenaline-induced effects were antagonized by simultaneously administered propranolol. T3 treatment had no influence on the parameters investigated. The results suggest that chronic β-adrenoceptor stimulation desensitizes myocardial adenylyl cyclase by at least two mechanisms: β-adrenoceptor downregulation leading to diminished signal transduction in the stimulatory pathway and Giα upregulation leading to sensitization of the inhibitory pathway. Such adaptation might protect the heart from chronic exposure to catecholamines in heart diseases with elevated plasma catecholamine levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00175468
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  • 4
    Electronic Resource
    Electronic Resource
    Evidence for CCKB receptors in the guinea-pig kidney: localization and characterization by [125I]gastrin binding studies and by RT-PCR (1998)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 358 (1998), S. 287-292 
    Details
    ISSN: 1432-1912
    Keywords: Key words Gastrin ; Cholecystokinin ; CCKB receptors ; Kidney ; Glomeruli ; Collecting duct
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two types of receptors for gastrin and cholecystokinin (CCK) have been identified in the gastrointestinal tract and in the central nervous system: CCKA and CCKB receptors. Here we report evidence for the expression of CCKB receptors in the guinea-pig kidney. Specific binding sites for [125I]gastrin were detected in sections of the guinea-pig kidney: Binding was saturable, pH-, temperature- and time-dependent, and specific for gastrin-related peptides. The potencies for inhibition of binding of [125I]gastrin were CCK-8 〉 gastrin 17-I 〉 CCKB receptor antagonist L-365,260 〉 des(SO3)CCK-8 〉 CCKA receptor antagonist L-364,718. Autoradiography demonstrated specific [125I]gastrin binding to medullary collecting ducts and to a much lesser extent to glomeruli, but not over other structures. CCKB receptor cDNA fragments were amplified by RT-PCR from total kidney, isolated tubuli and from tissues known to express CCKB receptors such as stomach and brain. The kidney might therefore be a previously unidentified site of action for gastrin and cholecystokinin-related peptides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005255
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  • 5
    Electronic Resource
    Electronic Resource
    Isoprenaline-induced increase in mRNA levels of inhibitory G-protein α-subunits in rat heart (1991)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 343 (1991), S. 609-615 
    Details
    ISSN: 1432-1912
    Keywords: G-protein-mRNA expression ; Rat heart ; Isoprenaline and triiodothyronine infusion ; Desensitization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Long-term β-adrenergic stimulation has been shown to desensitize the β-adrenoceptor/adenylyl cyclase signalling pathway at both the receptor and the G-protein level. To further elucidate the cellular mechanism of G-protein regulation we investigated the influence of prolonged infusion of isoprenaline (2.4 mg/kg·d) on myocardial mRNA levels of different G-protein α-subunits in rats. For comparison rats were treated with triiodothyronine (T3; 0.5 mg/kg·d) which induces cardiac hypertrophy like isoprenaline but has different effects on the adenylyl cyclase system. Isoprenaline- and T3-treated animals developed an increase in heart/body weight ratio of 41±3% and 27±4%, respectively (P〈0.05). Isoprenaline increased myocardial total RNA concentration by 39±6% (P〈0.05). Hybridization with 32P-labeled rat cDNAs demonstrated an expression rank order of Gsα-mRNA〉Giα-2-mRNA〉Giα−3-mRNA and no detectable expression of Giα−1-mRNA in rat myocardium. mRNA levels of Gsα Giα−2 and Giα−3 were 36.9±1.28, 10.7±1.07 and 3.7±0.19 pg/μg total RNA, respectively. Isoprenaline increased Giα−2 − and Giα−3-mRNA concentrations per μg total RNA by 49±18% and 27±710, respectively (P〈0.05). This effect was abolished by simultaneously administered propranolol (9.9 mg/kg·d), indicating a,β-adrenoceptor-mediated mechanism. In contrast, T3-induced cardiac hypertrophy was not accompanied by changes in Giα-mRNA expression. Gsaα-mRNA levels were unaffected by either treatment. In conclusion, long-term stimulation with isoprenaline in vivo induces a β-adrenoceptor-mediated increase in myocardial Giα−2 − and Giα−3-mRNA without affecting Gsα-mRNA. These results suggest that similar increases in myocardial Giα−2-mRNA in end-stage human heart failure may be at least partly explained by increased β-adrenergic stimulation due to increased sympathetic activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00184292
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  • 6
    Electronic Resource
    Electronic Resource
    Improved method for autoradiographic localization of ß-adrenoceptors using photoaffinity labelling (1993)
    Springer
    Naunyn-Schmiedeberg's archives of pharmacology 347 (1993), S. 494-499 
    Details
    ISSN: 1432-1912
    Keywords: ß-Adrenoceptors ; “Dipping” autoradiography ; Photoaffinity labeling ; Trichrome stain ; Cryosections ; Rat lung
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Contact autoradiography of tissue sections, using emulsion coated coverslips or X-ray films, is widely used to provide information about the regional distribution of receptors. This easy to perform, standard technique has the disadvantage of an image spread due to the gap between the radioactive source and the film. The present study describes a new technique which combines photoaffinity labeling of ß-adrenoceptors with “dipping” autoradiography and a modified trichrome stain. Incubation of 16 μm cryosections of rat lung tissue with the iodinated, photoaffintiy labeling, non-selective, ß-adrenergic agonist [125I]-cyanopindololazide II ([125I]-CYPA II) (100 pmol/1) in the absence or presence of 1 μmol (±)-propranolol revealed strong, specific ß-adrenoceptor binding to alveolar parenchyma and bronchial epithelium of large and small bronchioles, lesser binding to smooth muscle bundles of large airways and only sparse binding to the smooth muscle of small bronchioles or peripheral branches of pulmonary artery. With standard autoradiographic techniques, a similiar distribution of the label was obtained, although resolution and sensitivity were inferior. Staining of tissue sections through the photo-emulison by means of a modified Mallory's trichrome dye facilitated the discrimination between alveolar and bronchial epithelium, muscular and collagenous tissues. In conclusion, the photoaffinity labeling of ß-adrenoceptors with [125I]-CYPA II allows the use of “dipping” autoradiography. This technique, in combination with trichrome staining through the photoemulsion, results in an improved autoradiograpic image together with a better association of the label with distinct histological structures and the higher sensitivity of the method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00166741
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  • 7
    Electronic Resource
    Electronic Resource
    Muscarinic and β-adrenergic regulation of heart rate, force of contraction and calcium current is preserved in mice lacking endothelial nitric oxide synthase (1999)
    [s.l.] : Nature America Inc.
    Nature medicine 5 (1999), S. 331-334 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] 〉Nitric oxide (NO) is an ubiquitous signaling molecule produced from L-arginine by NO synthase (NOS). In the vasculature, NO mediates parasympathetic endothelium-dependent vasodilation. NO may also mediate the parasympathetic control of myocardial function. This is supported by the ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/6553
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  • 8
    Electronic Resource
    Electronic Resource
    Engineered heart tissue grafts improve systolic and diastolic function in infarcted rat hearts (2006)
    [s.l.] : Nature Publishing Group
    Nature medicine 12 (2006), S. 452-458 
    Details
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] The concept of regenerating diseased myocardium by implantation of tissue-engineered heart muscle is intriguing, but convincing evidence is lacking that heart tissues can be generated at a size and with contractile properties that would lend considerable support to failing hearts. Here we created ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nm1394
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  • 9
    Electronic Resource
    Electronic Resource
    Analysis of gene expression patterns in small amounts of human ventricular myocardium by a multiplex RNase protection assay (1998)
    Springer
    Journal of molecular medicine 76 (1998), S. 133-140 
    Details
    ISSN: 1432-1440
    Keywords: Key words Heart failure ; Human ; RNase protection assay ; Myocardial biopsies ; Gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  End-stage human heart failure is associated with changes in expression of steady-state messenger RNA (mRNA) levels. These changes correspond to alterations in protein levels and myocardial function and may have clinical implications regarding etiology, clinical state, or prognosis. However, analysis of mRNA levels in endomyocardial biopsies can be accomplished only by the quantitative polymerase chain reaction, which is difficult to standardize. The aim of the study was to evaluate whether the RNase protection assay is applicable to measure mRNAs of multiple genes simultaneously in small amounts of ventricular myocardium comparable to myocardial biopsies. Total RNA was prepared from left ventricular myocardium from terminally failing hearts with idiopathic (n=9) or ischemic cardiomyopathy (n=7) and from nonfailing control hearts (n=10). mRNA was measured by an optimized RNase protection assay for the β1-adrenoceptor, the stimulatory G protein α-subunit (Gsα), phospholamban, the calcium ATPase of the sarcoplasmic reticulum (SERCA), β-myosin heavy chain (β-MHC), and the atrial natriuretic peptide (ANP). We extracted 10.7±2.1 μg total RNA from three myocardial biopsies taken in vitro. All of the six genes were measurable in duplicate in a total of 7 μg RNA. mRNAs of β1-adrenoceptor, phospholamban, and SERCA were lower in failing than in nonfailing myocardium by 50%, 33%, and 42% respectively, whereas β-MHC and Gsα mRNAs were unchanged. mRNA of ANP was expressed at high levels only in the failing myocardium, providing a highly specific and sensitive marker for discriminating nonfailing and failing hearts. A direct comparison with ANP and Gsα levels obtained by Northern blot analysis with 7.5 μg total RNA showed a good correlation between the two methods. The RNase protection assay is thus a suitable method for simultaneous measurements of multiple mRNA levels in human myocardial biopsies. Changes in mRNA levels closely reflected those identified by other methods using larger amounts of RNA. Increased myocardial ANP mRNA levels determined by the RNase protection assay may serve as a molecular marker of heart failure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001090050201
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  • 10
    Electronic Resource
    Electronic Resource
    Protein phosphorylation in isolated trabeculae from nonfailing and failing human hearts (1996)
    Springer
    Molecular and cellular biochemistry 157 (1996), S. 171-179 
    Details
    ISSN: 1573-4919
    Keywords: human heart ; force of contraction ; protein phosphorylation ; phospholamban
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Disturbances in the cAMP production during β-adrenergic stimulation and alterations of Ca 2+ transport controlling proteins and their regulation in the sarcoplasmic reticulum might be involved in the pathogenesis of the failing human heart. Thus, we investigated the cAMP-mediated phosphorylation of phospholamban, troponin I and C-protein in electrically driven, intact isolated trabeculae carneae from nonfailing and failing (NYHA IV) human hearts in parallel to contractile properties on the same tissue samples. The increase in force of contraction induced by isoproterenol (0.2 μM) or pimobendan (100 μM), a phosphodiesterase inhibitor, was diminished in the failing human hearts compared to nonfailing hearts by 49% and 36%, respectively. Concomitantly the isoproterenol-induced phosphorylation (pmol P/mg homogenate protein) of phospholamban, troponin I and C-protein was reduced from 13.0 ± 2.4 (n = 4), 30.5 ± 1.5 (n = 5) and 11.0 ± 1.3 (n = 5) in the nonfailing heart to 5.2 ±0.6 (n = 13), 14.6 ± 2.2 (n = 16) and 7.1 ± 1.0 (n = 6) in the failing human heart, respectively. Pimobendan changed the phosphorylation state of these proteins similar to isoproterenol. The fact that combined addition of both agents or dibuturyl CAMP (1 mM) alone restored the phosphorylation capacity as observed in the control groups indicates that i) a reduced cAMP generation is related to the reduced phosphorylation of regulatory phosphoproteins located in the sarcoplasmic reticulum and contractile apparatus e.g. phospholamban, troponin I and C-protein, that ii) there is a relationship between protein phosphorylation state and contractile activity and that iii) no changes in the respective content of phosphoproteins are involved in the limitation of cAMP-mediated inotopic activity in the failing human heart. (Mol Cell Biochem 157: 171–179, 1996)
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227896
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