scholarly journals Negative Inotropic Effect of Cyclic AMP on the Isolated Canine Heart Muscle

1973 ◽  
Vol 110 (4) ◽  
pp. 409-410
Author(s):  
NAOFUMI IWATSUKI ◽  
KENICHI IWATSUKI
Keyword(s):  
Cyclic Amp ◽  
Heart Muscle ◽  
Negative Inotropic Effect ◽  
Inotropic Effect ◽  
Canine Heart

scholarly journals Evaluation of Negative Inotropic Effects of a Isoquinoline Alkaloid N-14

2021 ◽  
Vol 4 (3) ◽  
pp. 01-05
Author(s):  
Inoyat Jumayev
Keyword(s):  
Muscle Contraction ◽  
Papillary Muscle ◽  
Heart Muscle ◽  
Rat Heart ◽  
Cyclopiazonic Acid ◽  
Negative Inotropic Effect ◽  
Isoquinoline Alkaloid ◽  
Inotropic Effect ◽  
Inotropic Effects ◽  
Negative Inotropic Effects

In studies, the alkaloid 1-(2-Chloro-4,5-methylenedioxyphenyl)-2-hydroxyethyl-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline (N-14) had a negative inotropic effect on the activity of the papillary muscle contraction of the rat heart detected. Ca2+ ions from SR play an important role in the process of contraction of the heart muscle. With this in mind, the negative inotropic effect of the N-14 alkaloid was investigated with the modification of the accumulation processes of Ca2+ ions to SR. To clarify this, we examined the effects of the alkaloid being studied on SERCA2a and RyR2. To do this, the inhibitor of SERCA2a - cyclopiazonic acid (CPA) and RyR activator caffeine, which provide the accumulation of Ca2+ ions in SR, were used.

Relationship between the Effect on Calcium Turnover and Early Cardiotoxicity of Doxorubicin and 4'-EPI-Doxorubicin in Guinea Pig Heart Muscle

1980 ◽  
Vol 66 (6) ◽  
pp. 689-697 ◽  
Author(s):  
Fabrizio Villani ◽  
Luigia Favalli ◽  
Francesco Piccinini
Keyword(s):  
Guinea Pig ◽  
Heart Muscle ◽  
Myocardial Contractility ◽  
Negative Inotropic Effect ◽  
Experimental Models ◽  
Inotropic Effect ◽  
General Mechanism ◽  
Guinea Pig Heart ◽  
Membrane Bound ◽  
Guinea Pig Atria

Doxorubicin and 4'-epi-doxorubicin, two anthracycline derivatives with different cardiotoxic effects in experimental models, were found to decrease myocardial contractility in isolated guinea pig atria by significantly modifying calcium turnover. This effect seems to be mainly localized on the fast exchanging membrane-bound calcium, while these drugs do not significantly influence the intracellular stores of calcium. 4'-epi-doxorubicin, which induces a less negative inotropic effect than doxorubicin, produces a smaller inhibition of calcium turnover. This supports the hypothesis that the inhibition of calcium turnover and particularly of the fast exchanging calcium compartment is a general mechanism involved in the early anthracycline-induced cardiotoxicity.

Negative Inotropic Effect of Basic Fibroblast Growth Factor on Adult Rat Cardiac Myocyte

Circulation ◽  
1997 ◽  
Vol 96 (8) ◽  
pp. 2501-2504 ◽  
Author(s):  
Yuji Ishibashi ◽  
Yoshitoshi Urabe ◽  
Hiroyuki Tsutsui ◽  
Shintaro Kinugawa ◽  
Masaru Sugimachi ◽  
...  
Keyword(s):  
Growth Factor ◽  
Fibroblast Growth Factor ◽  
Basic Fibroblast Growth Factor ◽  
Cardiac Myocyte ◽  
Negative Inotropic Effect ◽  
Inotropic Effect ◽  
Fibroblast Growth ◽  
Adult Rat

Functional and autoradiographic characterization of dopamine D2-like receptors in the guinea pig heart

2002 ◽  
Vol 80 (6) ◽  
pp. 578-587 ◽  
Author(s):  
María de Jesús Gómez ◽  
Guy Rousseau ◽  
Réginald Nadeau ◽  
Roberto Berra ◽  
Gonzalo Flores ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Western Blot ◽  
Dopamine Receptors ◽  
Negative Inotropic Effect ◽  
Cyclase Activity ◽  
Inotropic Effect ◽  
Receptor Subtypes ◽  
Guinea Pig Heart ◽  
Additional Information ◽  
The Right

Dopamine receptors include the D1- (D1 and D5 subtypes) and D2-like (D2, D3, and D4 subtypes) families. D1-like receptors are positively and D2-like receptors negatively coupled to the adenylyl cyclase. Dopamine D2-like (D4 subtype) receptors have been identified in human and rat hearts. However the presence of D2 and D3 receptor subtypes is unclear. Furthermore, their role in cardiac functions is unknown. By autoradiographic studies of guinea pig hearts, we identified D3 and D4 receptors, using the selective radioligands [3H]-7-OH-DPAT and [3H]emonapride (YM-09151-2 plus raclopride). Western blot analysis confirmed D3 and D4 receptors in the right and left ventricle of the same species. Selective agonists of D3 and D4 receptors (±)-7-OH-DPAT and PD 168 077 (10–9 to 10–5 M, respectively) induced a significant negative chronotropic and inotropic effect in the isolated guinea pig heart preparation. Negative inotropic effect induced by PD 168 077 was associated with an inhibition in cyclase activity. No changes in cyclase activity were found with (±)-7-OH-DPAT. The aim of this study is to support the presence of D3 and D4 receptors in the heart. Although our results suggest that D3 and D4 receptors are functionally active in the heart, we need additional information with an antagonist and an agonist of improved potency and selectivity to understand the respective roles of D3 and D4 receptors in the cardiac functions.Key words: Dopamine receptors (D2, D3, D4 subtypes), autoradiography, Western blot, cAMP, heart.

Cholinergic stimulation modulates negative inotropic effect of cocaine on ferret ventricular myocardium

1996 ◽  
Vol 270 (2) ◽  
pp. H678-H684
Author(s):  
L. Miao ◽  
Z. Qiu ◽  
J. P. Morgan
Keyword(s):  
Response Curve ◽  
Negative Inotropic Effect ◽  
Ventricular Myocardium ◽  
Inotropic Effect ◽  
Dependent Manner ◽  
Cholinergic Stimulation ◽  
Concentration Dependent Manner ◽  
Cell Shortening ◽  
Inotropic State ◽  
Concentration Response Curve

We tested the hypothesis that the negative inotropic effect (NIE) of cocaine is mediated, at least in part, by cholinergic stimulation and can be correlated with the degree of adenosine 3',5'-cyclic monophosphate (cAMP) dependency of the inotropic state. Cardiac myocytes were isolated from left ventricles of ferrets and loaded with the fluorescent Ca2+ indicator indo 1. Cells were placed in physiological solution containing 2.0 mM Ca2+ and stimulated at 0.5 Hz and 30 degrees C. Cocaine decreased peak cell shortening and peak intracellular Ca2+ in a concentration-dependent manner (10(-8)-10(-4) M). The concentration-response curve of cocaine was shifted significantly downward compared with those of lidocaine and procaine in the same range of concentrations. Atropine (10(-6) M) shifted the concentration-response curve of cocaine, but not those of lidocaine and procaine, rightward, with a pA2 value (7.66) similar to that obtained with carbachol (7.99). With prior addition of isoproterenol (ISO, 10(-8) M) or increased Ca2+ (4.0 mM) to increase cell shortening to the same degree (approximately 60%), cocaine and carbachol decreased contractility to a significantly greater extent in ISO-stimulated myocytes. To clarify whether these treatments changed responsiveness of the contractile elements to Ca2+, the effect of 2,3-butanedione monoxime, an agent that interferes with the interaction of myosin and actin, was tested with previous addition of ISO or increased Ca2+, and no differential effect occurred. Therefore, we postulate that 1) the NIE of cocaine on myocytes is caused by decreased Ca2+ availability; 2) this effect is due to specific stimulation of cholinergic receptors in addition to other direct myocardial (probably local anesthetic) effects; and 3) the NIE correlates with the level of cAMP dependence of the inotropic state.

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