ABSTRACT
Introduction:
Cardiotonics and calcium channel blockers are drugs that alter intracellular Ca2+ and can affect the heart.
Objective:
To evaluate the effects of administration of verapamil and digoxin on heart morphology of rats subjected to interval training (IT).
Methods:
Male Wistar rats were divided into groups (n = 8): Control, Digoxin (30.0µg.kg-1/day), Verapamil (5.0 mg.kg-1/day), Trained, Trained+digoxin and Trained+verapamil. The IT was performed on a treadmill (60 min/day/60 days) concurrently with the drugs administration. Fragments of the left ventricle (LV) were collected for histological analysis.
Results:
Digoxin and verapamil increased the total area of the LV (p<0.002), capillary/LV area (p<0.01) and cardiomyocytes area (p<2.8e-10), and in the latter variable, verapamil promoted even greater effect than digoxin. The IT increased LV/BW (p<4e-05), the inner diameter of the LV (p<2.7e-6), the area of cardiomyocytes (p<1.8e-6), and reduced the [Lac] (p<2.6e-5). There was interaction between IT and drugs in the total area (p<9.8e-5), capillaries (p<0.04), cell/area (p<0.004) and cardiomyocytes area (p <2.0e-16).
Conclusions:
Digoxin promoted cardiomyocyte hypertrophy and when associated with IT, potentiated the hypertrophy. Verapamil was more efficient in increasing the cardiomyocytes area compared with digoxin, but only when isolated.
Keywords:
cardiotonic agents; calcium channel blockers; motor activity; heart
