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Alterations in cardiac performance in experimentally-induced diabetes
Pharmacology
|January 1, 1983
Summary
Streptozotocin (STZ) treatment in rats depressed atrial function but enhanced ventricular function. While isoproterenol sensitivity remained unchanged, ventricles showed calcium supersensitivity, suggesting altered calcium utilization in cardiac tissue.
Area of Science:
- Cardiovascular Physiology
- Endocrinology
- Pharmacology
Background:
- Diabetes mellitus is associated with cardiac dysfunction.
- Streptozotocin (STZ) is a commonly used agent to induce diabetes in animal models.
- Understanding the cardiac effects of STZ is crucial for diabetes research.
Purpose of the Study:
- To investigate the functional and biochemical responses of cardiac tissue to STZ treatment.
- To assess the effects of STZ on atrial and ventricular function.
- To determine alterations in beta-adrenoceptor sensitivity and calcium handling post-STZ.
Main Methods:
- Cardiac tissue (atria and ventricles) isolated from STZ-treated and control rats.
- Assessment of responses to isoproterenol (ISO) and calcium.
- Determination of beta-adrenoceptor number (Bmax) and affinity.
Main Results:
- STZ treatment depressed atrial function but enhanced right ventricular function 4 weeks post-treatment.
- No alteration in ISO sensitivity was observed in either tissue.
- Atrial calcium sensitivity was unchanged, while ventricular tissue exhibited calcium supersensitivity.
- A 36% decrease in beta-adrenoceptor Bmax without affinity change was noted after STZ.
Conclusions:
- STZ-induced diabetes alters cardiac function, specifically depressing atrial activity and enhancing ventricular performance.
- Ventricular enhancement is linked to altered calcium utilization, indicated by supersensitivity to calcium.
- Changes in beta-adrenoceptor density may contribute to the observed functional modifications in STZ-treated rats.