- Meeting abstract
The effect of insulin and enalapril on the potentiation of bradykinin-induced vasodilation by angiotensin-(1–7) in diabetes mellitus
Critical Care volume 7, Article number: P128 (2003)
In control normoglycemic rats, angiotensin-(1–7) [Ang-(1–7)] potentiates the bradykinin (BK)-induced vasodilation. We studied the effects of insulin and enalapril in the Ang-(1–7) and BK interaction in diabetes mellitus.
Design and methods
After 30 days of alloxan (40 mg/kg, intravenously), arteriolar reactivity was determined in vivo by intravital microscopy in anesthetized diabetic rats. The increase in arteriolar diameter (%) was measured before and after topical application of BK (1 pmol) and of Ang-(1–7) (100 pmol) + BK. Animals were treated acutely (4 IU, 4 hours before) or chronically (2 IU, 12 days) with insulin. The effect of enalapril (10 mg/kg per 21 days) and tetraethylammonium (90 pmol, topically), a potassium channel blocker, was also tested.
In diabetic rats, topical application of BK induced a small vasodilation (2.5 ± 0.8%), which was augmented by acute insulin (5.6 ± 0.8%, P < 0.05), chronic insulin (4.3 ± 0.2%, P < 0.05) and enalapril (5.3 ± 0.3%, P < 0.05) treatments. The Ang-(1–7) + BK association did not modify the BK-induced vasodilation in diabetic rats (2.5 ± 0.8 vs 3.4 ± 1.0%), in rats acutely treated with insulin (5.6 ± 0.8% vs 6.0 ± 0.8%) and in enalapril-treated animals (5.3 ± 0.3% vs 6.2 ± 0.2%). However, in animals with chronic insulin treatment, BK responses were potentiated by Ang-(1–7) (8.3 ± 0.5%, P < 0.05), and this potentiating effect was reversed in the presence of tetraethylammonium (5.5 ± 0.7%, P < 0.05).
These data may indicate that membrane hyperpolarization may contribute to the restoring effect of insulin on the potentiation of BK-induced vasodilation by Ang-(1–7) on diabetic microvessels.
Support by PRONEX and FAPESP.
Rights and permissions
About this article
Cite this article
Oliveira, M., Carvalho, M., Nigro, D. et al. The effect of insulin and enalapril on the potentiation of bradykinin-induced vasodilation by angiotensin-(1–7) in diabetes mellitus. Crit Care 7 (Suppl 3), P128 (2003). https://doi.org/10.1186/cc2324
- Potassium Channel
- Topical Application