Non-additive positive inotropic effects of amrinone and ouabain on cat papillary muscles

1984 ◽  
Vol 62 (9) ◽  
pp. 390-393 ◽  
Author(s):  
L. Brown ◽  
E. Erdmann
Keyword(s):  
Papillary Muscles ◽  
Inotropic Effects ◽  
Positive Inotropic Effects

scholarly journals The positive inotropic effects of OPC-18790, a new cardiotonic agent, in guinea-pig papillary muscles

1992 ◽  
Vol 58 ◽  
pp. 271
Author(s):  
Michio Yajima ◽  
Yoshihiro Hotta ◽  
Pao Chi Isao ◽  
Hiroaki Ando ◽  
Hirohiko Nomura ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Papillary Muscles ◽  
Inotropic Effects ◽  
Cardiotonic Agent ◽  
Positive Inotropic Effects

Influence of glucose metabolism on ouabain-induced changes in the transmembrane potential and contraction of human heart in vitro

1970 ◽  
Vol 48 (12) ◽  
pp. 801-812 ◽  
Author(s):  
K. Prasad ◽  
John C. Callaghan
Keyword(s):  
Action Potential ◽  
Heart Surgery ◽  
Open Heart Surgery ◽  
Metabolic Inhibitors ◽  
Papillary Muscles ◽  
Force Of Contraction ◽  
Inotropic Effects ◽  
M 10 ◽  
Positive Inotropic Effects ◽  
Induced Changes

Effects of glucose, anoxia, iodoacetate, and 2,4-dinitrophenol on the ouabin-induced changes in the simultaneously recorded transmembrane action potential and contraction of 72 human papillary muscle strips obtained from 36 patients undergoing corrective open heart surgery were investigated. Ouabain (10−8M, 10−9M, 10−10M) produced a shortening of the action potential duration (APD) and an increase in the force of contraction in the muscle. Non-oxygenated glucose-free solution, iodoacetate (10−5M), and 2,4-dinitrophenol (10−6M) produced partial to complete inhibition of the positive inotropic effects of ouabain (10−8M or 10−9M) in the papillary muscles. The shortening of the APD produced by ouabain was further enhanced in the presence of the above metabolic inhibitors. As the glucose level was raised (0, 5, 10, 20, 30 mM), anoxic papillary muscles responded to ouabain by a progressive increase in the force of contraction and a parallel increase in the APD. Glucose (30 mM) was effective in restoring the positive inotropic effects of ouabain in DNP-poisoned muscle while it was ineffective in doing so in the muscle poisoned with both IAA and DNP. These results indicate the requirement of energy for the positive inotropic effects of ouabain in cardiac muscle.

Interaction of Halothane with α- and β-Adrenoceptor Stimulations in Rat Myocardium

1997 ◽  
Vol 86 (1) ◽  
pp. 147-159 ◽  
Author(s):  
Jean-Luc Hanouz ◽  
Bruno MD Riou ◽  
Laurent Massias ◽  
Yves Lecarpentier ◽  
Pierre Coriat
Keyword(s):  
Positive Inotropic Effect ◽  
Negative Inotropic Effect ◽  
Left Ventricular ◽  
Inotropic Effect ◽  
Papillary Muscles ◽  
Inotropic Effects ◽  
Beta Adrenoceptor ◽  
Low Load ◽  
Positive Inotropic Effects

Background Halothane induces negative inotropic and lusitropic effects in myocardium. It has been suggested that halothane potentiates beta-adrenoceptor stimulation. However, its effects on the inotropic response to alpha-adrenoceptor stimulation and its effects on the lusitropic effects of alpha- and beta-adrenoceptor stimulation are unknown. Methods The effects of halothane (0.5 and 1 minimum alveolar concentration [MAC]) on the inotropic responses induced by phenylephrine (10(-8) to 10(-4) M) and isoproterenol (10(-8) to 10(-4) M) were studied in rat left ventricular papillary muscles in vitro (in Krebs-Henseleit solution at 29 degrees C, pH 7.40, with 0.5 mM calcium and stimulation frequency at 12 pulses/min). The lusitropic effects were studied in isotonic (R1) and isometric (R2) conditions. Results One MAC halothane induced a negative inotropic effect (54 +/- 3%, P < 0.05), increased R1 (109 +/- 3%, P < 0.05), and decreased R2 (88 +/- 2%, P < 0.05). In control groups, phenylephrine (137 +/- 7%, P > 0.05) and isoproterenol (162 +/- 6%, P < 0.05) induced a positive inotropic effect. Halothane did not significantly modify the positive inotropic effect of calcium, suggesting that it did not modify the inotropic reserve of papillary muscles. In contrast, 1 MAC halothane enhanced the positive inotropic effects of phenylephrine (237 +/- 19%, P < 0.05) and isoproterenol (205 +/- 11%, P < 0.05). Halothane did not modify the lusitropic effect of phenylephrine under high or low load. In contrast, 1 MAC halothane impaired the positive lusitropic effect of isoproterenol under low load (P < 0.05), whereas it did not modify the positive lusitropic effect of isoproterenol under high load. Conclusions At clinically relevant concentrations, halothane potentiated the positive inotropic effects of both alpha- and beta-adrenoceptor stimulation. Furthermore, halothane alters the positive lusitropic-effect of beta-adrenoceptor stimulation under low load.

Contractile effects of cardiac neuropeptides in isolated canine atrial and ventricular muscles

1989 ◽  
Vol 257 (4) ◽  
pp. H1082-H1087 ◽  
Author(s):  
D. F. Rigel ◽  
I. L. Grupp ◽  
A. Balasubramaniam ◽  
G. Grupp
Keyword(s):  
Isometric Force ◽  
Contractile Force ◽  
Adrenergic Blockade ◽  
Canine Heart ◽  
Inotropic Action ◽  
Inotropic Effects ◽  
Calcitonin Gene ◽  
Positive Inotropic Effects ◽  
The Right ◽  
Ventricular Trabeculae

Contractile effects of the cardiac neuropeptides vasoactive intestinal polypeptide (VIP), peptide histidine isoleucine (PHI), neuropeptide Y (NPY), calcitonin gene-related peptide (CGRP), and neurotensin (NT) were compared with those of l-isoproterenol (ISO) in isolated canine atrial and ventricular trabeculae muscles stimulated to contract at 1 Hz. In ventricular muscles, ISO, VIP, and PHI augmented developed isometric force by approximately 100%. VIP and PHI were three times and 1/10, respectively, as potent as ISO. VIP also exhibited positive inotropic effects in atrial trabeculae. The contractile responses to VIP were unchanged after beta-adrenergic blockade with nadolol at a concentration (10 microM) that shifted the ISO dose-response curve two to three orders of magnitude to the right. In atrial and ventricular trabeculae, NPY (1 microM) attenuated contractile force by 36 +/- 8 and 30 +/- 4%, respectively. Each peptide also caused comparable increases or decreases in the rate of development of force and the rate of relaxation. CGRP and NT caused no significant changes in developed force in either atrial or ventricular muscles in concentrations up to 1 microM. Our results indicate a potential positive inotropic action of endogenous VIP and PHI and a cardiodepressant effect of endogenous NPY in the canine heart.

scholarly journals Coronary vasodilation and positive inotropism by urocortin in the isolated rat heart

2001 ◽  
Vol 169 (1) ◽  
pp. 177-183 ◽  
Author(s):  
K Terui ◽  
A Higashiyama ◽  
N Horiba ◽  
KI Furukawa ◽  
S Motomura ◽  
...  
Keyword(s):  
Rat Heart ◽  
Isolated Rat Heart ◽  
Coronary Vasodilation ◽  
Duration Of Action ◽  
Inotropic Effects ◽  
Vasodilator Effect ◽  
Cardiac Effects ◽  
Positive Inotropic Effects ◽  
Isolated Rat

Corticotropin-releasing factor (CRF) has a coronary vasodilator effect and a positive inotropic effect on the isolated rat heart. Recently, expression of CRF receptor type 2 (CRF-R2) has been demonstrated in the heart. In addition, urocortin (Ucn), a new member of the CRF family, has been reported to have much greater affinity for CRF-R2 than CRF. It is suggested that the cardiac effects of Ucn may be more potent than those of CRF. We compared the effect of Ucn with that of CRF on isolated rat heart. The effects of Ucn were then analyzed to determine whether these effects were mediated by CRF receptors and/or any other mediators under the following conditions: perfusion buffer containing (1) alpha-helical CRF 9-41, (2) indomethacin, (3) N(G)-nitro-l -arginine methylester and (4) propranolol. Ucn exhibited a greater effect with a longer duration of action than CRF. Indomethacin significantly attenuated the vasodilator effects of Ucn (P<0.05). CRF receptor antagonist diminished both coronary vasodilation and the positive inotropic effects of Ucn (P<0.05). These results suggest that the cardiac effects of Ucn may be mediated by a CRF receptor, and prostaglandins may be involved in the vasodilator effect.

Sign in / Sign up

Export Citation Format

Share Document