The effects of calcium antagonists on extracellular potassium accumulation during global ischaemia in isolated perfused rat hearts

1991 ◽  
Vol 5 (6) ◽  
pp. 1035-1041 ◽  
Author(s):  
J. B. Heijnis ◽  
R. Coronel ◽  
P. A. van Zwieten
Keyword(s):  
Calcium Antagonists ◽  
Extracellular Potassium ◽  
Potassium Accumulation ◽  
Global Ischaemia ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Isolated Perfused Rat Hearts

scholarly journals Activity of phosphorylase in total global ischaemia in the rat heart A phosphorus-31 nuclear-magnetic-resonance study

1981 ◽  
Vol 196 (1) ◽  
pp. 171-178 ◽  
Author(s):  
I A Bailey ◽  
S R Williams ◽  
G K Radda ◽  
D G Gadian
Keyword(s):  
Inhibitory Effect ◽  
Heart Tissue ◽  
Nuclear Magnetic Resonance Study ◽  
Cytosolic Ph ◽  
Global Ischaemia ◽  
Rat Hearts ◽  
Perfused Rat Hearts ◽  
Tissue Acidosis ◽  
Good Agreement

1. The uptake and subsequent phosphorylation of deoxyglucose into perfused rat hearts was monitored by 31P n.m.r. 2. The accumulated deoxyglucose 6-phosphate provided (a) an independent method for measuring cytosolic pH in the normoxic and ischaemic heart tissue and (b) a way of studying the activity of phosphorylase during ischaemia. 3. The cytosolic pH measured from the 31P n.m.r. resonance position of deoxyglucose 6-phosphate is in good agreement under all conditions studied with that obtained previously from the Pi resonances. This eliminates any possible doubts about the use of Pi for measuring intracellular pH. 4. Deoxyglucose 6-phosphate in vitro inhibits phosphorylase b but not phosphorylase a. Its inhibitory effect on glycogenolysis during ischaemia is monitored by measuring tissue acidosis by n.m.r. In the initial stages of ischaemia phosphorylase activity is not inhibited, whereas after about 5 min approx. 50% of the activity is inhibited. These observations are interpreted in terms of the relative contributions of phosphorylase a and the AMP-dependent phosphorylase b activities during ischaemia.

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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