Experimental diabetes in rats abolished the reflex reduction of renal sympathetic nerve activity in response to acute volume expansion (1.9% vs -14%/mm Hg in controls).
Does experimental diabetes impair cardiopulmonary reflex control of circulation in rats?
Experimental diabetes in rats abolishes the cardiopulmonary reflex control of circulation during acute volume expansion, while responses to serotonin remain preserved.
Absolute Event Rate: 1.9% vs -14%
The aim of the present study was to evaluate the sensitivity of the cardiopulmonary receptors in experimental diabetes induced by streptozotocin by the use of 2 different methods: (1) administration of increasing doses of serotonin to analyze peak changes of arterial pressure and heart rate for each given dose in conscious intact normal and diabetic rats; (2) expanding blood volume with the use of dextran (6%) to produce similar increases in left ventricular end-diastolic pressure to quantify the arterial pressure, heart rate, and renal sympathetic nerve activity in sinoaortic, denervated, anesthetized normal and diabetic rats. Blood samples were collected to measure blood glucose. Diabetic rats showed hyperglycemia (22+/-0. 7 versus 7+/-0.2 mmol/L), reduced body weight (226+/-12 versus 260+/-4 g) and heart rate (294+/-14 versus 350+/-10 bpm), and similar arterial pressure (104+/-4 versus 113+/-4 mm Hg) when compared with control rats. Serotonin induced significant bradycardia and hypotension, which were similar and proportional to the dose injected in both groups. Mean arterial pressure and heart rate decreases in response to volume overload were significantly lower in diabetic than in control rats. The reflex reduction of the renal sympathetic nerve activity as expressed by percentage changes in nerve activity in response to increasing left end-diastolic pressure was abolished in diabetic animals (1.9+/-0.8% versus -14+/-4%/mm Hg in controls). These results showed an impairment of cardiopulmonary reflex control of circulation in diabetes during acute volume expansion. The normal responses to serotonin administration indicated that the cardiopulmonary reflex is still preserved in diabetic rats.
Oliveira et al. (Fri,) conducted a other in Experimental diabetes. Experimental diabetes vs. Normal control rats was evaluated on Reflex reduction of renal sympathetic nerve activity in response to increasing left end-diastolic pressure. Experimental diabetes in rats abolished the reflex reduction of renal sympathetic nerve activity in response to acute volume expansion (1.9% vs -14%/mm Hg in controls).
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