scholarly journals The inotropic effects of ammonia on isolated perfused rat hearts and the mechanisms involved

2011 ◽  
Vol 214 (23) ◽  
pp. 4048-4054 ◽  
Author(s):  
Q. Zhang ◽  
Z. Meng
Keyword(s):  
Inotropic Effects ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts

Impaired cardiac function in rats with healed myocardial infarction: cellular vs. myocardial mechanisms

1994 ◽  
Vol 266 (1) ◽  
pp. C29-C36 ◽  
Author(s):  
J. Y. Cheung ◽  
T. I. Musch ◽  
H. Misawa ◽  
A. Semanchick ◽  
M. Elensky ◽  
...  
Keyword(s):  
Systolic Dysfunction ◽  
Systolic Pressure ◽  
Left Ventricular ◽  
Lv Function ◽  
Inotropic Effects ◽  
Cell Shortening ◽  
Subendocardial Ischemia ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts

The inotropic responsiveness of isolated perfused rat hearts and single left ventricular (LV) myocytes to extracellular Ca2+ ([Ca2+]o) was examined 3 wk after ligation of left main coronary artery. Myocytes isolated from myocardial infarcted (MI) hearts were 10% longer. At [Ca2+]o of 1.1 mM, cell shortening as well as intracellular Ca2+ concentration dynamics were similar between MI and sham LV myocytes. At [Ca2+]o of 4.9 mM, maximal extent of cell shortening was significantly less in MI myocytes (16 +/- 1 vs. 22 +/- 1%), and peak intracellular Ca2+ concentration was also substantially lower. Thus, under conditions of high [Ca2+]o, decreased sarcolemmal Ca2+ influx and Ca2+ release during excitation-contraction may contribute to systolic dysfunction in MI hearts. Perfused working hearts and isovolumic heart preparations with infarcted LV displayed depressed maximal systolic pressure and decreased sensitivity to the inotropic effects of [Ca2+]o. Our data also indicate that, in addition to possible abnormalities in the contractile response of single myocytes, global factors such as loss of functional myocardium, altered chamber geometry, tissue fibrosis, and/or subendocardial ischemia contributed to depressed LV function in post-MI hearts perfused at physiological [Ca2+]o.

Chaotic Heart Rate Dynamics in Isolated Perfused Rat Hearts

1989 ◽  
pp. 215-224 ◽  
Author(s):  
Joseph P. Zbilut ◽  
Gottfried Mayer-Kress ◽  
Paul A. Sobotka ◽  
Michael O’Toole ◽  
John X. Thomas
Keyword(s):  
Heart Rate ◽  
Rat Hearts ◽  
Heart Rate Dynamics ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts

Glucocorticoid receptor activation in isolated perfused rat hearts

1989 ◽  
Vol 256 (2) ◽  
pp. C219-C225 ◽  
Author(s):  
S. M. Czerwinski ◽  
E. E. McKee ◽  
R. C. Hickson
Keyword(s):  
Glucocorticoid Receptor ◽  
Triamcinolone Acetonide ◽  
Deae Cellulose ◽  
Potassium Phosphate ◽  
Receptor Activation ◽  
Receptor Complexes ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Cellulose Binding ◽  
Isolated Perfused Rat Hearts

The formation of unactivated and activated glucocorticoid receptor complexes was studied in intact, isolated, perfused rat hearts in the presence of [3H]triamcinolone acetonide. Receptor activation, as quantified by the DNA-cellulose-binding assay, began to increase within 30 s of perfusion and reached a final steady-state level (t 1/2 = 4.6 min) with 46% of the steroid-receptor complexes bound to DNA-cellulose. With the use of a linear potassium phosphate (KP) gradient (5-400 mM), unactivated receptors eluted from DEAE-cellulose anion exchange columns at approximately 250 mM KP. Two activated receptor forms appeared, which eluted either in the wash fraction (binder IB) or between 50 and 100 mM KP (binder II) and occurred with half times of 1.3 and 2.7 min, respectively. Postperfusion cytosol preparation did not markedly influence the results as receptor binding was reduced by 10% or less when a 100-fold excess of unlabeled triamcinolone acetonide was included in the homogenizing buffer. We conclude from these results that glucocorticoids are able to exert a direct effect on the heart through binding to their own receptor in the absence of endogenous hormones. The time dependency of receptor activation supports a physiological role for this process. However, activation rates, determined from conformational changes associated with altered DEAE-cellulose elution profiles and appearance of activated receptor forms, occur earlier and may not be coordinated with the rate of activation as quantified by DNA-cellulose binding.

Monitoring of mitochondrial membrane potential in isolated perfused rat heart

1984 ◽  
Vol 247 (4) ◽  
pp. H508-H516
Author(s):  
R. A. Kauppinen ◽  
I. E. Hassinen
Keyword(s):  
Membrane Potential ◽  
Mitochondrial Membrane Potential ◽  
Mitochondrial Membrane ◽  
Optical Methods ◽  
Perfused Heart ◽  
Rat Hearts ◽  
Carbonyl Cyanide ◽  
Perfused Rat Hearts ◽  
Beating Rate ◽  
Isolated Perfused Rat Hearts

Optical methods were tested for measuring the membrane potential changes of mitochondria in isolated perfused rat hearts. Safranin was found to be rapidly taken up by the Langendorff-perfused heart, and after loading with the dye there was practically no washout of the stain during perfusion with Krebs-Ringer bicarbonate solution. Staining with safranin induced the appearance of an intense absorption band in the reflectance spectrum of the heart, but the absorbance spectrum changes were not useful for monitoring the mitochondrial membrane potential changes because of interference by endogenous hemoproteins. The fluorescence intensity, however, responded in a manner which indicated that its changes originated from dye attached to the mitochondria. A decrease of the fluorescence was found on energizing the mitochondria by decreasing the cellular energy consumption by arrest induced by 18 mM K+ or by decreasing the beating rate of an electrically paced heart from 5 Hz to the endogenous ventricular frequency of 1.5 Hz. In hearts arrested by Ca2+ depletion, 18 mM K+ did not affect the safranin fluorescence. This was taken to indicate that under these conditions the safranin fluorescence was not sensitive to the plasma membrane potential. The uncoupler carbonyl cyanide m-chlorophenylhydrazone induced an intense enhancement of safranin fluorescence in the perfused heart, demonstrating that the probe is sensitive to mitochondrial membrane potential.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Effects and mechanisms of curcumin on the hemodynamic variablesof isolated perfused rat hearts

2016 ◽  
Vol 46 ◽  
pp. 166-173 ◽  
Author(s):  
Erkan KILINÇ ◽  
Ziya KAYGISIZ ◽  
Bedri Selim BENEK ◽  
Kenan GÜMÜŞTEKİN
Keyword(s):  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts
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