caa a22 4500 469078057 CHVBK 20180323132940.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00168740 doi (NATIONALLICENCE)springer-10.1007/BF00168740 Contribution of both α- and β-adrenoceptors to the inotropic effects of catecholamines in the rabbit heart [Elektronische Daten] [Ulrich Jahnel, Barbara Kaufmann, Martin Rombusch, Hermann Nawrath] Summary: The functional role of α-adrenoceptors was investigated in different parts of the rabbit heart. Phenylephrine (PE) caused a marked increase in force of contraction (Fc) and a prolongation of the action potential (AP) in preparations from the left atrium and the right ventricle. The response was less pronounced in the right atrium and in the left ventricle, whereas APs of spontaneously beating sinoatrial preparations remained completely unchanged. Phentolamine as well as the diesters phorbol 12,13 dibutyrate (PDBu) or 12-O-tetradecanoylphorbol-13-acetate (TPA) eliminated the effects of PE. The contribution of a-adrenoceptors to the effects of adrenaline (Adr) and noradrenaline (NA) on Fc was determined in preparations from the right ventricle. Phentolamine and the phorbol diesters reduced the effects of Adr and NA by about 30 to 60%; the remaining response was abolished by propranolol. It can be derived from our experiments that, in some parts of the rabbit heart, a considerable amount of the effects of Adr and NA is due to the stimulation of a-adrenoceptors. The present findings therefore support the view that, in the rabbit heart, the maximally effective drive of the heart requires the stimulation of both α- and β-adrenoceptors. The inhibitory effects of phorbol diesters on the α-adrenoceptor-mediated response indicate that the activation of protein kinase C (PKC) specifically uncouples α-adrenoceptors from the effector system, whereas the response to β-adrenoceptor stimulation remains unchanged. Springer-Verlag, 1992 Rabbit heart nationallicence Phenylephrine nationallicence Noradrenaline nationallicence Adrenaline nationallicence Isoprenaline nationallicence Phorbol ester nationallicence Jahnel Ulrich Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Kaufmann Barbara Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Rombusch Martin Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Nawrath Hermann Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 665-672 0028-1298 346:6<665 1992 346 210 https://doi.org/10.1007/BF00168740 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00168740 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Jahnel Ulrich Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut NATIONALLICENCE 700 1- Kaufmann Barbara Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut NATIONALLICENCE 700 1- Rombusch Martin Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut NATIONALLICENCE 700 1- Nawrath Hermann Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 665-672 0028-1298 346:6<665 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer