BLOOD-PRESSURE AND HEART-RATE RELATIONSHIPS DURING CERVICAL SYMPATHETIC AND VAGUS NERVE-STIMULATION IN STREPTOZOTOCIN-DIABETIC RATS

Linear regressions were calculated between blood pressure and heart rate changes during the stimulation of peripheral cut end of cervical sympathetic and vagus nerve in the streptozotocin diabetic rats (65 mg/kg) and age-matched controls. Slopes of blood pressure (mmHg, abscissa)-heart rate (beat/minute, ordinate) relationships of diabetic rats (9.87+/-1.46, mean+/-S.E.M., n=8) were significantly steeper (P < 0.05) than those of age-matched controls (5.12 +/- 0.63, n = 7). In the control rats, blood pressure and heart rate were rather equally changed during autonomic nerve stimulation. In contrast, in the diabetic rats, heart rate was markedly changed but blood pressure was little changed during the electrical stimulation of the cervical autonomic nerves. Chronotropic effect was exaggerated but inotropic one was disturbed in the heart of streptozotocin diabetic rat when cervical sympathetic nerve was stimulated.