scholarly journals Effects of High-Energy Phosphate Depletion and Repletion on the Dynamics and Electrocardiogram of Isolated Rat Hearts

1968 ◽  
Vol 23 (4) ◽  
pp. 519-530 ◽  
Author(s):  
JAMES SCHEUER ◽  
S. WILLIAM STEZOSKI
1991 ◽  
Vol 261 (6) ◽  
pp. H2082-H2090 ◽  
Author(s):  
M. Avkiran ◽  
M. J. Curtis

A novel dual lumen aortic cannula was designed and constructed to permit independent perfusion of left and right coronary beds in isolated rat hearts without necessitating the cannulation of individual arteries. Stability of the dual-perfusion preparation was shown to be similar to that of the conventional Langendorff preparation, in terms of coronary flow, heart rate, and high-energy phosphate content. The independence of left and right perfusion beds was confirmed by unilateral infusion of disulfine blue dye and spectrophotometric detection of the dye in ventricular homogenates. Transient cessation of flow to the left coronary bed resulted in severe ventricular arrhythmias upon reperfusion, as in conventional models of regional ischemia and reperfusion. The dual-perfusion model is technically undemanding, reproducible, inexpensive, and can be used in several species. It enables studies with 1) regional low flow ischemia, 2) regional zero-flow ischemia without coronary ligation (with attendant damage to vasculature), 3) selective application of drugs or interventions to the ischemic-reperfused zone, and 4) selective application of components of ischemia and reperfusion to a site anatomically relevant to ischemic heart disease.


2005 ◽  
Vol 288 (6) ◽  
pp. H3011-H3015 ◽  
Author(s):  
Kenya Nishizawa ◽  
Paul E. Wolkowicz ◽  
Tadashi Yamagishi ◽  
Ling-Ling Guo ◽  
Martin M. Pike

Whereas activation of ATP-dependent potassium (KATP) channels greatly improves postischemic myocardial recovery, the final effector mechanism for KATP channel-induced cardioprotection remains elusive. RhoA is a GTPase that regulates a variety of cellular processes known to be involved with KATP channel cardioprotection. Our goal was to determine whether the activity of a key rhoA effector, rho kinase (ROCK), is required for KATP channel-induced cardioprotection. Four groups of perfused rat hearts were subjected to 36 min of zero-flow ischemia and 44 min of reperfusion with continuous measurements of mechanical function and 31P NMR high-energy phosphate data: 1) untreated, 2) pinacidil (10 μM) to activate KATP channels, 3) fasudil (15 μM) to inhibit ROCK, and 4) both fasudil and pinacidil. Pinacidil significantly improved postischemic mechanical recovery [39 ± 16 vs. 108 ± 4 mmHg left ventricular diastolic pressure (LVDP), untreated and pinacidil, respectively]. Fasudil did not affect reperfusion LVDP (41 ± 13 mmHg) but completely blocked the marked improvement in mechanical recovery that occurred with pinacidil treatment (54 ± 15 mmHg). Substantial attenuation of the postischemic energetic recovery was also observed. These data support the hypothesis that ROCK activity plays a role in KATP channel-induced cardioprotection.


1992 ◽  
Vol 52 (5) ◽  
pp. 483-488 ◽  
Author(s):  
Robert H. Messier ◽  
Patrick W. Domkowski ◽  
Hamdy M. Aly ◽  
Anwar S. Abd-Elfattah ◽  
Donald G. Crescenzo ◽  
...  

1976 ◽  
Vol 230 (6) ◽  
pp. 1744-1750 ◽  
Author(s):  
TB Allison ◽  
SP Bruttig ◽  
Crass MF ◽  
RS Eliot ◽  
JC Shipp

Significant alterations in heart carbohydrate and lipid metabolism are present 48 h after intravenous injection of alloxan (60 mg/kg) in rats. It has been suggested that uncoupling of oxidative phosphorylation occurs in the alloxanized rat heart in vivo, whereas normal oxidative metabolism has been demonstrated in alloxan-diabetic rat hearts perfused in vitro under conditions of adequate oxygen delivery. We examined the hypothesis that high-energy phosphate metabolism might be adversely affected in the alloxan-diabetic rat heart in vivo. Phosphocreatine and ATP were reduced by 58 and 45%, respectively (P is less than 0.001). Also, oxygen-dissociation curves were shifted to the left by 4 mmHg, and the rate of oxygen release from blood was reduced by 21% (P is less than 0.01). Insulin administration normalized heart high-energy phosphate compounds. ATP production was accelerated in diabetic hearts perfused in vitro with a well-oxygenated buffer. These studies support the hypothesis that oxidative ATP production in the alloxan-diabetic rat heart is reduced and suggest that decreased oxygen delivery may have a regulatory role in the oxidative metabolism of the diabetic rat heart.


1997 ◽  
Vol 29 (5) ◽  
pp. 2358-2359
Author(s):  
M. Eugene ◽  
G. Bauza ◽  
L. Esteves-Lima ◽  
L. Le Moyec ◽  
I. Gandjbakhch

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