scholarly journals Slowing of shortening velocity of rat cardiac myocytes by adenosine receptor stimulation regardless of beta-adrenergic stimulation.

1995 ◽  
Vol 486 (3) ◽  
pp. 679-688 ◽  
Author(s):  
K T Strang ◽  
R M Mentzer ◽  
R L Moss
Keyword(s):  
Cardiac Myocytes ◽  
Adenosine Receptor ◽  
Adrenergic Stimulation ◽  
Shortening Velocity ◽  
Receptor Stimulation ◽  
Beta Adrenergic ◽  
Rat Cardiac Myocytes

scholarly journals Different effects of alpha- and beta-adrenergic stimulation on cytosolic pH and myofilament responsiveness to Ca2+ in cardiac myocytes.

1992 ◽  
Vol 71 (4) ◽  
pp. 870-882 ◽  
Author(s):  
G Gambassi ◽  
H A Spurgeon ◽  
E G Lakatta ◽  
P S Blank ◽  
M C Capogrossi
Keyword(s):  
Cardiac Myocytes ◽  
Adrenergic Stimulation ◽  
Cytosolic Ph ◽  
Beta Adrenergic

Differential sensitization of cardiac actions of adenosine in rats after chronic theophylline treatment

1993 ◽  
Vol 264 (5) ◽  
pp. H1634-H1643 ◽  
Author(s):  
H. T. Lee ◽  
C. I. Thompson ◽  
J. Linden ◽  
F. L. Belloni
Keyword(s):  
Adenosine Receptor ◽  
Radioligand Binding ◽  
Specific Binding ◽  
Maximal Response ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic ◽  
Adenosine Receptor Agonists ◽  
Receptor Agonists ◽  
Competition Binding ◽  
Isolated Atria

To determine the effect of chronic adenosine receptor blockade on atrial responsiveness, we administered theophylline to rats in their drinking water (0.6 mg/ml) for 2 wk. Inotropic and chronotropic responses to the adenosine receptor agonists N6-cyclopentyladenosine (CPA) and 5'-(N-ethylcarboxamido)-adenosine (NECA) were then measured in isolated atria from treated and control animals. The indirect (antiadrenergic) actions of CPA and NECA on force and rate, measured during beta-adrenergic receptor stimulation by isoproterenol, were markedly sensitized (2- to 10-fold reductions in the agonist concentration needed to obtain a half-maximal response) after theophylline. The sensitization was homologous because inotropic and chronotropic responses to carbachol were not affected by theophylline. The direct negative inotropic and chronotropic actions of CPA and NECA, measured without concomitant beta-adrenergic stimulation, were not sensitized after theophylline. The number of atrial A1-receptors, measured by antagonist radioligand binding (maximum specific binding at saturation), was increased by 22% in theophylline-treated rats [66.2 +/- 3.4 vs. 54.3 +/- 1.9 (control) fmol/mg protein, P < 0.05]. Competition binding indicated that the fraction of coupled (high-affinity) receptors was unchanged. The number of ventricular A1-receptors was increased to a similar extent without any change in coupling. Thus chronic dietary theophylline upregulated cardiac A1-adenosine receptors without changing coupling state or affinity and sensitized rat atria to the indirect, antiadrenergic, inhibitory inotropic and chronotropic actions of adenosine receptor agonists.

Differences in affinity of cardiac beta-adrenergic receptors for [3H]dihydroalprenolol

1986 ◽  
Vol 250 (3) ◽  
pp. H490-H497
Author(s):  
K. H. Muntz ◽  
T. A. Calianos ◽  
D. T. Vandermolen ◽  
J. T. Willerson ◽  
L. M. Buja
Keyword(s):  
Cardiac Myocytes ◽  
Adrenergic Receptors ◽  
Dissociation Constants ◽  
Specific Binding ◽  
Scatchard Analysis ◽  
Adrenergic Stimulation ◽  
Beta Adrenergic Receptors ◽  
Beta Adrenergic ◽  
Number Of Binding Sites ◽  
Tissue Compartments

We performed quantitative light microscopic autoradiography of [3H]dihydroalprenolol (DHA) binding to frozen sections of canine myocardium to test the hypothesis that there are differences in the density or affinity of beta-adrenergic receptors on various tissue compartments. In one study, with concentrations of [3H]DHA from 0.34 to 5.1 nM, specific binding to cardiac myocytes was saturable, whereas nonspecific binding was linear with ligand concentration. Arterioles had more specific grain counts than muscle cells (P less than 0.0001), and Scatchard analysis showed that the arterioles had a much higher affinity for [3H]DHA than myocytes. In a second study with lower concentrations of [3H]DHA (0.19-1.98 nM), binding to the arterioles saturated, whereas binding to the cardiac myocytes did not. Specific binding to arterioles was significantly higher (P less than 0.0001) than binding to myocytes at all concentrations of [3H]DHA. The dissociation constants for the subendocardial and subepicardial myocytes were 1.57 and 1.71 nM, respectively, while the dissociation constant for the arterioles was 0.26 nM. The maximum number of binding sites was 911 grains/0.9 X 10(-2) mm2 for subepicardial myocytes, 936 for subendocardial myocytes, and 986 for arterioles. The large nerves accompanying an epicardial artery also demonstrated specific [3H]DHA binding. Thus this study has demonstrated major differences in the distribution and affinity of beta-adrenergic receptors, which may help to explain various physiological responses to beta-adrenergic stimulation.

Adrenergic Stimulation Regulates Na+/Ca2+Exchanger Expression in Rat Cardiac Myocytes

2000 ◽  
Vol 32 (4) ◽  
pp. 611-620 ◽  
Author(s):  
Kish L Golden ◽  
Q Ivy Fan ◽  
Bin Chen ◽  
Jun Ren ◽  
Jessica O»Connor ◽  
...  
Keyword(s):  
Cardiac Myocytes ◽  
Adrenergic Stimulation ◽  
Rat Cardiac Myocytes

scholarly journals NO donors potentiate the β‐adrenergic stimulation of I Ca,L and the muscarinic activation of I K,ACh in rat cardiac myocytes

2002 ◽  
Vol 540 (2) ◽  
pp. 411-424 ◽  
Author(s):  
Najah Abi‐Gerges ◽  
Gabor Szabo ◽  
Angela S. Otero ◽  
Rodolphe Fischmeister ◽  
Pierre‐François Méry
Keyword(s):  
Cardiac Myocytes ◽  
Adrenergic Stimulation ◽  
No Donors ◽  
Rat Cardiac Myocytes ◽  
Stimulation Of
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