caa a22 4500 477120830 CHVBK 20180405111636.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00408662 doi (NATIONALLICENCE)springer-10.1007/BF00408662 The effect of insulin-like growth factor-1 on adult rat cardiac contractility [Elektronische Daten] [Nicholas Freestone, Samo Ribaric, William Mason] There is increasing evidence that insulin-like growth factor-1 (IGF-1) may play a role in both physiological and pathophysiological events in the mammalian myocardium. The present study investigated the acute effects of IGF-I on isometric force development in isolated rat cardiac muscle and on intracellular calcium (Ca2+) handling in isolated cardiac myocytes. IGF-I had a positive inotropic effect on rat ventricular papillary muscles increasing force development by 17.8 ± 4.6%, 18.5 ± 5.8% and 11.9 ± 4.9% (n = 12-20) at concentrations of 1, 10 and 100 ng/ml respectively. Isoprenaline increased tension in these papillary muscles by 56.7 ± 7.7% at a concentration of 100 nM (n = 22). In comparison, insulin increased papillary muscle force development by 11.6 ± 3.2%, 17.7 ± 4.1% and 19.7 ± 5.6% at concentrations of 1, 10 and 100 nM respectively (n = 16-20). In the single cardiac myocyte IGF-1 increased, the peak cytosolic free Ca2+ concentration, the amplitude of the Ca2+ transient and the time to peak Ca2+ as measured with the fluorescent bioprobe Indo-1 AM. The positive inotropic response to IGF-1 by rat ventricular muscle is therefore associated with a rise in free, peak cytosolic Ca2+ in isolated cardiac myocytes. Increasing insulin concentrations (1-1000 nM) elicited a progressive elevation in isometric force and free, cytosolic Ca2+. In contrast, in the presence of IGF-1, the maximal rise in isometric force and free cytosolic Ca2+ were both observed at 10 ng/ml. Recent reports have suggested that IGF-1 may act on the mammalian myocardium when administered chronically, but this study is amongst the first to demonstrate an acute effect of IGF-I on the mammalian heart. IGF-1 may prove then to be a novel cardioactive agent in both normal and pathophysiological states. Kluwer Academic Publishers, 1996 IGF-I nationallicence cardiac myocytes nationallicence inotropic nationallicence calcium fluorescence nationallicence isometric force nationallicence Freestone Nicholas Laboratory of Neural and Secretory Signalling, Department of Neurobiology, Babraham Institute, Babraham, Cambridge, UK aut Ribaric Samo Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia aut Mason William Laboratory of Neural and Secretory Signalling, Department of Neurobiology, Babraham Institute, Babraham, Cambridge, UK aut Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 163-164/1(1996-03-01), 223-229 0300-8177 163-164:1<223 1996 163-164 11010 https://doi.org/10.1007/BF00408662 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00408662 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Freestone Nicholas Laboratory of Neural and Secretory Signalling, Department of Neurobiology, Babraham Institute, Babraham, Cambridge, UK aut NATIONALLICENCE 700 1- Ribaric Samo Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia aut NATIONALLICENCE 700 1- Mason William Laboratory of Neural and Secretory Signalling, Department of Neurobiology, Babraham Institute, Babraham, Cambridge, UK aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 163-164/1(1996-03-01), 223-229 0300-8177 163-164:1<223 1996 163-164 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer