caa a22 4500 469078618 CHVBK 20180323132942.0 cr unu---uuuuu 170328e19921101xx s 000 0 eng 10.1007/BF00169000 doi (NATIONALLICENCE)springer-10.1007/BF00169000 Positive inotropic response to 5-HT in human atrial but not in ventricular heart muscle [Elektronische Daten] [Ulrich Jahnel, Johanna Rupp, Rudolf Ertl, Hermann Nawrath] Summary: The effects of 5-hydroxytryptamine (5-HT) on force of contraction (FC), action potential (AP) and calcium current (ICa) were studied in human right atrial and left ventricular heart muscle. 5-HT exerted a concentration-dependent increase in FC in multicellular atrial preparations; the EC50 was approximately 3 × 10−7 mol/l. Maximal increases in FC (252±58% of control values; means ± SEM, n=6) were obtained at 5-HT 10−5 mol/l. At this concentration, ICa was increased four- to sevenfold in enzymatically isolated atrial myocytes. In contrast, ventricular preparations did not respond to 5-HT; FC, AP and ICa remained unaffected. In the same preparations, FC was increased by isoprenaline three- to fourfold. These results confirm the observation that 5-HT induces a positive inotropic effect in the human atrium, possibly mediated by activation of the adenylyl cyclase — cyclic AMP system. Our study demonstrates, however, the complete lack of functional 5-HT receptors, with respect to changes in FC, in the human ventricle. Since the positive inotropic effect of 5-HT in the human heart is obviously restricted to the atrium, our findings question the concept of developing 5-HT receptor agonists for the treatment of heart failure. Springer-Verlag, 1992 Human heart nationallicence Force of contraction nationallicence 5-Hydroxytryptamine nationallicence Ca2+ current nationallicence Jahnel Ulrich Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Rupp Johanna Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut Ertl Rudolf 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 346/5(1992-11-01), 482-485 0028-1298 346:5<482 1992 346 210 https://doi.org/10.1007/BF00169000 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00169000 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- Rupp Johanna Pharmakologisches Institut der Universität Mainz, Obere Zahlbacher Strasse 67, W-6500, Mainz, Federal Republic of Germany aut NATIONALLICENCE 700 1- Ertl Rudolf 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 346/5(1992-11-01), 482-485 0028-1298 346:5<482 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer