Reflex control of arterial pressure and heart rate in short-term streptozotocin diabetic rats

Dall’Ago, Pedro; Silva, V. O. K.; Angelis, Kátia De; Irigoyen, Maria Cláudia; Fazan, Rubens; Salgado, Hélio César

doi:10.1590/s0100-879x2002000700013

Cited by 47 publications

(31 citation statements)

References 19 publications

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“…We have previously described vagal function impairment in diabetic rats. 13,19,36,37 In the present study, exercise training increased vagal tonus in control rats. Furthermore, exercise training induced an attenuation of vagal tonus impairment in diabetic rats, because no difference was observed between TDO rats and SO rats.…”

Section: Discussionsupporting

confidence: 57%

Role of Exercise Training in Cardiovascular Autonomic Dysfunction and Mortality in Diabetic Ovariectomized Rats

Souza

Flues²,

Paulini³

et al. 2007

Hypertension

135

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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.

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Section: Discussionsupporting

confidence: 57%

Role of Exercise Training in Cardiovascular Autonomic Dysfunction and Mortality in Diabetic Ovariectomized Rats

Souza

Flues²,

Paulini³

et al. 2007

Hypertension

135

View full text Add to dashboard Cite

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“…In fact, our studies demonstrated that electric vagal stimulation, as well as myocardial muscarinic receptor stimulation by methacholine injections determined an increase in the bradycardic response of short-term STZ-induced diabetic animals, suggesting efferent pathway impairment in the reflex arc (43). The increased bradycardia induced by methacholine injection could represent hypersensitivity of receptors linked to the characteristic reduction in parasympathetic activity shown by these animals.…”

Section: Baroreflex Control In Experimental Diabetesmentioning

confidence: 53%

Cardiovascular control in experimental diabetes

Angelis

Schaan

Maeda

et al. 2002

Braz J Med Biol Res

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Several studies have reported impairment in cardiovascular function and control in diabetes. The studies cited in this review were carried out from a few days up to 3 months after streptozotocin administration and were concerned with the control of the circulation. We observed that early changes (5 days) in blood pressure control by different peripheral receptors were maintained for several months. Moreover, the impairment of reflex responses observed after baroreceptor and chemoreceptor stimulation was probably related to changes in the efferent limb of the reflex arc (sympathetic and parasympathetic), but changes also in the central nervous system could not be excluded. Changes in renal sympathetic nerve activity during volume expansion were blunted in streptozotocin-treated rats, indicating an adaptive natriuretic and diuretic response in the diabetic state. The improvement of diabetic cardiovascular dysfunction induced by exercise training seems to be related to changes in the autonomic nervous system. Complementary studies about the complex interaction between circulation control systems are clearly needed to adequately address the management of pathophysiological changes associated with diabetes.

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“…Autonomic nervous system dysfunction, indicated by an increase in vagal tone or a decline in sympathetic tone to the heart may reduce HR, as suggested by Jackson and Carrier in 1983 (15), but previous data from our laboratory showed that 5-day diabetic rats had in fact reduced vagal function, whereas their sympathetic tone was not significantly affected (12). Perhaps the enhanced bradycardia induced by electrical vagal stimulation or methacholine administration could account in part for the final result of lower HR (22). This bradycardia may also be caused by a change in the electrophysiological properties of the sinoatrial node, since intrinsic HR is reduced (12).…”

Section: Discussionmentioning

confidence: 99%

Relationship between cardiovascular dysfunction and hyperglycemia in streptozotocin-induced diabetes in rats

Schaan

Dall’Ago

Maeda

et al. 2004

Braz J Med Biol Res

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Streptozotocin (STZ)-induced diabetes in rats is characterized by cardiovascular dysfunction beginning 5 days after STZ injection, which may reflect functional or structural autonomic nervous system damage. We investigated cardiovascular and autonomic function, in rats weighing 166 ± 4 g,[5][6][7]14,30, 45, and 90 days after STZ injection (N = 24,33,27,14,and 13, respectively). Arterial pressure (AP), mean AP (MAP) variability (standard deviation of the mean of MAP, SDMMAP), heart rate (HR), HR variability (standard deviation of the normal pulse intervals, SDNN), and root mean square of successive difference of pulse intervals (RMSSD) were measured. STZ induced increased glycemia in diabetic rats vs control rats. Diabetes reduced resting HR from 363 ± 12 to 332 ± 5 bpm (P < 0.05) 5 to 7 days after STZ and reduced MAP from 121 ± 2 to 104 ± 5 mmHg (P = 0.007) 14 days after STZ. HR and MAP variability were lower in diabetic vs control rats 30-45 days after STZ injection (RMSSD decreased from 5.6 ± 0.9 to 3.4 ± 0.4 ms, P = 0.04 and SDMMAP from 6.6 ± 0.6 to 4.2 ± 0.6 mmHg, P = 0.005). Glycemia was negatively correlated with resting AP and HR (r = -0.41 and -0.40, P < 0.001) and with SDNN and SDMMAP indices (r = -0.34 and -0.49, P < 0.01). Even though STZ-diabetic rats presented bradycardia and hypotension early in the course of diabetes, their autonomic function was reduced only 30-45 days after STZ injection and these changes were negatively correlated with plasma glucose, suggesting a metabolic origin.

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Reflex control of arterial pressure and heart rate in short-term streptozotocin diabetic rats

Cited by 47 publications

References 19 publications

Role of Exercise Training in Cardiovascular Autonomic Dysfunction and Mortality in Diabetic Ovariectomized Rats

Role of Exercise Training in Cardiovascular Autonomic Dysfunction and Mortality in Diabetic Ovariectomized Rats

Cardiovascular control in experimental diabetes

Relationship between cardiovascular dysfunction and hyperglycemia in streptozotocin-induced diabetes in rats

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