We addressed the hypothesis that hypercaloric diets induce hyperkinetic hypertension irrespective of day-night cycle and locomotor activity that is associated with altered cardiac myosin isozymes. Normotensive rats with implanted radiotelemetry pressure transducers were fed increasing amounts of coconut fat (8, 16, and 24%, each for 2 wk) corresponding to 20–47% of total calories from fat. Thereafter, increasing amounts of sucrose (16, 32, and 50%) and fructose (50%) were added to the 24% fat diet corresponding to 13–40% of total calories from sugar. In contrast to the fat diets, the 32% and 50% sucrose diets as well as the 50% fructose diets increased ( P < 0.05) blood pressure (systolic maximum +13 mmHg, diastolic maximum +4 mmHg, mean maximum +7 mmHg) and heart rate (maximum +50 beats/min) irrespective of the day-night cycle and the unaltered locomotor activity. Furthermore, body weight increased ( P < 0.05) during the 32% and 50% sucrose feedings. The increased blood pressure and heart rate normalized after rats were fed a regular chow. We concluded that an excessive caloric intake results in hyperkinetic hypertension that increases the myosin V1proportion.
A versatile telemetry system for continuous measurement of heart rate, body temperature and locomotor activity in free-ranging ruminants