Cinnamaldehyde protects from the hypertension associated with diabetes

Here we investigated cinnamaldehyde (CA) effect on diabetes-induced hypertension. Insulin deficiency was induced by streptozotocin while, insulin resistance by fructose. Rats were left 8 weeks or 12 weeks after STZ or fructose administration respectively. CA (20 mg kg(-1) day(-1)) was daily administered in the last 6 weeks. Then, blood pressure (BP) was recorded. Isolated Aorta reactivity to phenylephrine (PE), KCl, acetylcholine (ACh) was studied as well as nitric oxide (NO) generation plus Ca(2+) influx. Insulin deficiency was associated with elevated BP, increased response to PE and KCl, decreased response to ACh and impaired NO generation. CA treatment prevented hyperglycemia and its associated impaired vascular reactivity. Insulin resistance was associated with elevated BP while, CA prevented this elevation. Insulin resistance increased response to PE and KCl, decreased response to ACh, while CA treatment normalized response to KCl and PE but not to ACh. Insulin resistance was accompanied with reduced NO generation but exaggerated Ca(2+) influx while CA restored normal Ca(2+) influx but did not affect NO generation. In conclusion, CA prevents development of hypertension in insulin deficiency and insulin resistance through normalization of vascular contractility in addition to its insulinotropic effect in insulin deficiency. (C) 2011 Elsevier Ltd. All rights reserved.