Category Archives: Myocardium

Kinetics of purine release from ischemic isolated guinea pig heart (part 14)

Further studies of the release and metabolism of adenosine by ischemic hearts of various species are a prerequisite to designing a new class of cardioprotective drugs that act through endogenous adenosine and its metabolites. The cardioprotective properties of inosine , … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 13)

Surprisingly, insufficient attention has been given to purines other than adenosine , although some of them possess interesting biological properties. Inosine has a cardioprotective effect and coronary vasodilatory action , and it potentiates adenosine-induced vasodilation . Uric acid is a … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 12)

An improvement in adenosine measurement in epicardial surface transudate has been introduced , and a threefold increase in the interstitial level of adenosine following 30 s of global ischemia was reported . Our data are in surprisingly good agreement with … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 11)

  Many studies have provided abundant evidence for enhanced adenosine production during myocardial ischemia or hypoxia, but in most of these the time of insult was within a range of minutes . The question of whether there is a threshold … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 10)

The principal findings are as follows: 1. The basal release of adenosine from perfused guinea pig hearts was very low, at the limit of detection, whereas the release of adenosine metabolites was much higher and easily detectable by HPLC. Uric … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 9)

DISCUSSION TPR from ischemic hearts did not increase linearly in parallel with the duration of ischemia (Figure 3). Basal TPR (30.9±1.4 nmol/min, n=33) and TPR observed following 15, 30 and 60 s of coronary occlusion did not differ significantly, whereas … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 8)

In control hearts uric acid was the major component of TPR (92%) (Figure 2). During the first minute of reperfusion after brief ischemia (15 to 30 s), uric acid still accounted for 80% to 90% of TPR; after long lasting … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 7)

One minute ischemia was followed by a five- to sixfold rise in inosine and in hypoxanthine plus xanthine release, and by a twofold rise in uric acid release (Figure 1C). Interestingly, adenosine release increased significantly after coronary occlusion lasting as … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 6)

The basal level of adenosine in the effluent was either not detectable (in 16 of 33 hearts) or just above the limit of detection, ie, 0.1 nmol/min (in 17 of 33 hearts). Metabolites of adenosine – inosine, hypoxanthine plus xanthine, … Continue reading

Kinetics of purine release from ischemic isolated guinea pig heart (part 5)

RESULTS Calculations and data analysis: Release of purine metabolites in the effluent was expressed in nmol/min (the product of metabolite concentration, in nmol/mL, and coronary flow rate, in mL/min).Total purine release (TPR) consisted of the release of adenosine plus inosine … Continue reading