Spontaneously diabetic BB/W rats were compared with age-matched regular Wistar and nondiabetic BB/W rats to determine whether the presence of diabetes would alter cardiovascular regulation appreciably. Systolic and mean blood pressures measured with the tail-cuff method from 12 to 26 wk of age tended to be slightly higher in diabetic than nondiabetic BB/W rats, but the differences were not significant. Mean pressures recorded from indwelling catheters in the same rats at 28 wk of age also did not differ significantly, thereby verifying that the diabetic rats were not hypertensive. To measure baroreflex sensitivity, heart-rate responses were elicited reflexly by elevating blood pressure with phenylephrine or lowering it with sodium nitroprusside. Although reflex bradycardia elicited with phenylephrine was the same, reflex tachycardia elicited with sodium nitroprusside was more pronounced in diabetic BB/W than other rats. Underlying autonomic mechanisms were then assessed by repeating the baroreflex tests after either cholinergic blockade with methylatropine or β-adrenergic blockade with propranolol. Magnitude of reflex bradycardia after inhibition by either cholinergic or β-adrenergic blockade still did not differ between rat groups but that of reflex tachycardia remained significantly stronger in diabetic BB/W than other rats. These results collectively show that, although diabetic BB/W rats remained normotensive, they had enhanced reflex tachycardia that persisted even after efferent autonomic blockade. The failure to develop higher pressures with time further indicates that without additional manipulation, these rats cannot be used experimentally to simulate the simultaneous presence of hypertension in diabetic patients.
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Original Articles| November 01 1991
Normotensive Diabetic BB/W Rats Show Enhanced Reflex Tachycardia
Address correspondence and reprint requests to Dr. Ruben D. Buiiag, Department of Pharmacology, University of Kansas Medical Center, 39th and Rainbow Boulevard, Kansas City, KS 66103.
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Dora Krizsan-Agbas, Ruben D Buñag; Normotensive Diabetic BB/W Rats Show Enhanced Reflex Tachycardia. Diabetes 1 November 1991; 40 (11): 1504–1510. https://doi.org/10.2337/diab.40.11.1504
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