Effects of Diabetic Hyperglycemia on Central Ang-(1-7)-Mas-R-nNOS Pathways in Spontaneously Hypertensive Rats

Area of Science:

• Neuroscience
• Cardiovascular Science
• Endocrinology

Background:

• Hypertension is a leading cause of stroke.
• Diabetes exacerbates hypertension and stroke risk.
• The central angiotensin-(1-7) pathway's role in diabetic hypertension is unclear.

Purpose of the Study:

• To investigate the central angiotensin-(1-7) pathway in spontaneously hypertensive rats with diabetic hyperglycemia.
• To determine the link between central angiotensin-(1-7) and stroke risk markers.
• To assess the effect of angiotensin-(1-7) on blood pressure in this model.

Main Methods:

• Western Blot and ELISA to measure protein expression of Ang-(1-7) and Mas-R-nNOS in rat brain.
• Induction of diabetic hyperglycemia using streptozotocin (STZ).
• Analysis of plasma brain natriuretic peptide (BNP) and arterial blood pressure.

Main Results:

• STZ administration attenuated central Ang-(1-7) levels and downregulated the Ang-(1-7)-Mas-R-nNOS pathway, especially in spontaneously hypertensive rats.
• Inhibition of oxidative stress improved Ang-(1-7) levels in diabetic spontaneously hypertensive rats.
• Central Ang-(1-7) stimulation or oxidative stress blockade lowered systolic blood pressure in diabetic spontaneously hypertensive rats.

Conclusions:

• The Ang-(1-7) signaling pathway plays a role in adaptive responses to diabetic hypertension.
• Enhancing the Ang-(1-7)-Mas-R-nNOS system may prevent cardiovascular and cerebrovascular dysfunction in hypertensive individuals, particularly those with diabetes.