caa a22 4500 469078073 CHVBK 20180323132941.0 cr unu---uuuuu 170328e19921201xx s 000 0 eng 10.1007/BF00168739 doi (NATIONALLICENCE)springer-10.1007/BF00168739 Characterization of the antagonism with metoprolol, ICI 147,798, pindolol, mepindolol and bopindolol on the responses of the rat left atria to isoprenaline [Elektronische Daten] [Ailsa Surman, Sheila Doggrell] Summary: The aim of the study was to determine whether the antagonism with pindolol, mepindolol and bopindolol at the β1-adrenoceptor of the rat left atria, a tissue with plenty of spare β1-adrenoceptors for isopren aline maximum responses, was readily reversible or not. The effects of these drugs were compared to those of metoprolol, a readily reversible, and of ICI 147,798, an irreversible β-adrenoceptor antagonist. Metoprolol at 10−7 and 10−6 M, ICI 147,798, pindolol, bopindolol (all at 10−8 and 10−7 M) and mepindolol at 10−9 and 10−8M inhibited the cardiac stimulation responses to a small extent, which is indicative of membrane stabilizing activity, and also caused surmountable antagonism of isoprenaline responses. The inhibitory effects on the isoprenaline responses of metoprolol and pindolol were readily reversible, that of mepindolol was slowly reversible and those of ICI 147,798 and bopindolol were not reversed in 3 h. The inhibitory effects on isoprenaline responses of metoprolol at 10−6 M, pindolol and bopindolol at 10−7 M and mepindolol at 10−8 M were at equilibrium, which is indicative of reversible, whereas the inhibitory effects of ICI 147,798 were increased, which is indicative of irreversible antagonism, when the β-blocker treatment time was increased from 1 to 2 h. We conclude that the antagonism with pindolol at the β1-adrenocep-tors of the rat left atria is readily reversible, that of mepindolol is slowly reversible and that of bopindolol is very slowly reversible. Springer-Verlag, 1992 Pindolol nationallicence Mepindolol nationallicence Bopindolol nationallicence β1-Adrenoceptors nationallicence Rat left atria nationallicence Surman Ailsa Department of Pharmacology, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand aut Doggrell Sheila Department of Pharmacology, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand aut Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 657-664 0028-1298 346:6<657 1992 346 210 https://doi.org/10.1007/BF00168739 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00168739 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Surman Ailsa Department of Pharmacology, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand aut NATIONALLICENCE 700 1- Doggrell Sheila Department of Pharmacology, School of Medicine, University of Auckland, Private Bag 92019, Auckland, New Zealand aut NATIONALLICENCE 773 0- Naunyn-Schmiedeberg's Archives of Pharmacology Springer-Verlag 346/6(1992-12-01), 657-664 0028-1298 346:6<657 1992 346 210 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer