Hemodynamic and autonomic response to acute hemorrhage in streptozotocin-induced diabetic rats

Abstract

BackgroundThe various autonomic control systems lead to characteristic changes in heart rate (HR) and blood pressure (BP) during acute hemorrhage. However, cardiovascular autonomic neuropathy due to diabetes mellitus may interfere with the normal compensation for hemorrhage.Materials and methodsA controlled graded bleeding (6 - 36% loss of estimated total blood volume: ETBV) was performed in streptozotocin-induced diabetic rats (STZ rats) under a conscious state. Hemodynamic and autonomic responses to acute hemorrhage were examined using analysis of BP-HR variability. The effects of dextran treatment after hemorrhage were also examined.ResultsA significant reduction in mean arterial pressure began at 12% ETBV loss in STZ rats and 18% in the control rats, respectively. When blood loss reached 18% of TEBV, the decrease in HR was prominent in STD rats due to the activation of a parasympathetic drive, as indicated by the increase in high frequency (HF; 0.75~3.0 Hz) power in HR variability, while in the control rats this response was not observed. The administration of dextran prevented the activation of the parasympathetic drive in STZ rats during hemorrhaging. In the control rats, the dextran treatment sustained the initial increase in HR with reduced HF power in HR variability.ConclusionSTZ rats showed different hemodynamic and autonomic responses to acute hemorrhage from the control rats. STZ rats were prone to develop bradycardiac hypotension characterized by marked parasympathetic activation during hemorrhaging. This finding suggests enhancement of the Bezold-Jarisch reflex in STZ rats. Dextran treatment to maintain a normovolemic hemorrhage state inhibits this reflex.

The Effects of Green Tea Consumption on Cardiometabolic Alterations Induced by Experimental Diabetes

“…In the present study, we observed in rats with STZ-induced diabetes a reduction in AP and HR associated with a decrease in HRV and APV as previously described [10, 41, 42]. On the other hand, there are reports of increased blood pressure [43–45] or no change in STZ-induced diabetic rats [46].…”

Renal denervation in an animal model of diabetes and hypertension: Impact on the autonomic nervous system and nephropathy

“…Thus the net effect was that the sympathovagal balance was reduced in these rats, which was also shown in non-hypertensive diabetic rats [31]. Again, renal denervation compensated this derangement, resulting in a sympathovagal balance almost at the levels of the controls (SHR).…”

Impaired blood pressure recovery to hemorrhage in obese Zucker rats with orthopedic trauma

“…2A). A similar decrease in heart rates after losing Ͼ18% of total blood volume was recently demonstrated in the streptozotocin-treated type 1 diabetic rats due to elevated Bezold-Jarish reflex and decreased baroreflex (4). Although an impaired baroreflex is demonstrated in OZ (6, 17, and 37), whether the decreased heart rate following moderate hemorrhage in OZ is the result of altered baroreflex control and/or an elevated Bezold-Jarish reflex has not been determined.…”