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Positive inotropic action of saponins on isolated atrial and papillary muscles from the guinea‐pig
Author(s) -
Enomoto Yoshikazu,
Ito Katsuaki,
Kawagoe Yasushi,
Mono Yasunori,
Yamasaki Yasundo
Publication year - 1986
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1986.tb09494.x
Subject(s) - practolol , isoprenaline , inotrope , chronotropic , chemistry , ouabain , contraction (grammar) , medicine , endocrinology , haemolysis , reserpine , propranolol , guinea pig , sodium , heart rate , organic chemistry , stimulation , blood pressure , immunology
1 The effects of several saponins of animal and plant origin on the contractile activity of atrial and papillary muscles of the guinea‐pig were tested. In a concentration of 1 × 10 −5 M, holothurin‐A (HL‐A), holothurin‐B, echinoside‐A, echinoside‐B and sakuraso‐saponin (Saku) exhibited positive inotropic and chronotropic actions whereas desacyl‐jego‐saponin and ginsenoside‐Rd did not. 2 Saponins having a positive inotropic action caused haemolysis of rabbit erythrocytes whereas those without inotropic action did not cause haemolysis. 3 The positive inotropic action of saponins was not affected by practolol, chlorpheniramine, cimetidine and indomethacin. 4 Verapamil (10 −6 M) inhibited the inotropic actions due to HL‐A and isoprenaline (10 −8 M) to the same extent but had a small efect on those due to ouabain (10 −7 M). 5 In high K + (30 mM K + ) medium where the action potential and the contraction were depressed, HL‐A, Saku and isoprenaline restored the action potential and the contraction of the ‘slow response’ type whereas ouabain failed to do so. 6 In normal medium HL‐A and Saku reduced the resting membrane potential by 15–20 mV. 7 These results suggest that modification of the Ca channel is involved in the positive inotropic action of saponins.