Abstract-Diabetes and menopause markedly increase the risk of cardiovascular disease in women. The objective of the present study was to investigate the effects of exercise training on cardiovascular autonomic dysfunction and on total mortality in diabetic female rats undergoing ovarian hormone deprivation. Female Wistar rats were divided into ovariectomized groups: sedentary and trained controls and sedentary and trained diabetic rats (streptozotocin, 50 mg/kg IV). Trained groups were submitted to an exercise training protocol on a treadmill (8 weeks). The baroreflex sensitivity was evaluated by heart rate responses to arterial pressure changes. Heart rate variability was determined using the SD of the basal heart rate. Vagal and sympathetic tonus were evaluated by pharmacological blockade. Diabetes impaired baroreflex sensitivity (Ϸ55%), vagal tonus (Ϸ68%), and heart rate variability (Ϸ38%). Exercise training improved baroreflex sensitivity and heart rate variability in control and diabetic groups in relation to their sedentary groups. Trained control rats presented increased vagal tonus compared with that of sedentary ones. The sympathetic tonus was reduced in the trained diabetic group as compared with that of other studied groups. Significant correlations were obtained between heart rate variability and vagal tonus with baroreflex sensitivity. Mortality, assessed during the training period, was reduced in trained diabetic (25%) rats compared with mortality in sedentary diabetic rats (60%). Together, these findings suggest that decreases in baroreflex sensitivity and heart rate variability may be related to increased mortality in female diabetic subjects and that improved autonomic regulation induced by exercise training may contribute to decreased mortality in this population.

Background: Because cardiomyopathy is the leading cause of death in diabetic patients, the determination of myocardial function in diabetes mellitus is essential. In the present study, we provide an integrated approach, using noninvasive echocardiography and invasive hemodynamics to assess early changes in myocardial function of diabetic rats.

Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.

Studies were conducted in rats to determine the effect of maternal diabetes and the consequent hyperglycemia on cardiovascular function in the offspring. Diabetes was induced in pregnant Wistar rats through streptozotocin injection (50 mg/kg). Cardiovascular parameters were measured in 2-mo-old offspring animals of diabetic (OD, n ϭ 12) and control rats (OC, n ϭ 8). Arterial pressure (AP), heart rate (HR), baroreflex sensitivity, and vascular responsiveness to phenylephrine (PH) and sodium nitroprusside (SN) were measured. Angiotensinconverting enzyme (ACE) activity in heart, kidney, and lung was determined. OD rats exhibited increases in systolic AP (138 Ϯ 8 vs. 119 Ϯ 6 mmHg, OD vs. OC), with no change in HR (342 Ϯ 21 vs. 364 Ϯ 39 beats per minute (bpm), OD vs. OC). The reflex tachycardia elicited by SN was reduced in OD rats, as indicated by the slope of the linear regression (Ϫ2.2 Ϯ 0.4 vs. Ϫ3.6 Ϯ 0.8 bpm/mmHg, OD vs. OC). Vascular responsiveness to PH was increased 63% in OD rats compared with OC. OD rats showed increases in ACE activity in heart, kidney, and lung (1.13 Ϯ 0.24, 3.04 Ϯ 0.86, 40.8 Ϯ 8.9 vs. 0.73 Ϯ 0.19, 1.7 Ϯ 0.45, 28.1 Ϯ 6 nmol His-Leu ⅐ min Ϫ1 mg protein Ϫ1 , OD vs. OC). Results suggest that diabetes during pregnancy affects cardiovascular function in offspring, seen as hypertension, baroreflex dysfunction, and activation of tissue renin-angiotensin system. cardiovascular; heart rate; development; angiotensin-converting enzyme; renin-angiotensin system; hyperglycemia EVIDENCE SUGGESTS THAT THE mother's lifestyle may have longlasting effects on offspring. For example, smoking, alcohol consumption, and presence of disease states such as diabetes and hypertension during pregnancy all affect fetal development (8,27). Alterations in fetal development could contribute to pathologies in the adult. With regard to diabetes, even when treated, the maternal disease has profound consequences on the fetus, seen as changes in brain, pancreas, lung, kidney, and heart (2, 14, 21, 44).To study diabetes in the experimental setting, chemical toxins have been widely used. Streptozotocin (STZ) is a pancreatic toxin that induces hyperglycemia, hypoinsulinemia, polyuria, and weight loss in rats (9,28,38,45). When STZinduced hyperglycemia is present during pregnancy, there are changes in fetal development and metabolism, including growth restriction and abnormal pancreatic function (5, 22, 36). Epidemiological and animal studies have shown that low birth weight increases the incidence of cardiovascular disease and diabetes mellitus in adulthood (3). Intrauterine growth restriction produced by placental insufficiency in pregnant rats was associated with marked elevation in blood pressure of the offspring (1). Adult offspring of STZ-diabetic rats also showed signs of cardiovascular dysfunction, seen as a reduced response to endothelium-dependent vasodilators and enhanced norepinephrine-induced vasoconstriction (23).There is evidence for an association between the development of diabetes and the activation of the reni...