Enalapril Prevents Impaired Nitric Oxide Synthase-Dependent Dilatation of Cerebral Arterioles in Diabetic Rats

Anna K. Trauernicht, Hong Sun, Kaushik P Patel, William Mayhan

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Background and Purpose - Our goal was to identify the effects of chronic treatment with enalapril on cerebrovascular dysfunction and endothelial nitric oxide synthase (eNOS) protein in diabetic rats. Methods - Rats were assigned to 1 of 4 groups: nondiabetic, diabetic, nondiabetic/enalapril-treated, and diabetic/enalapril-treated groups. Rats assigned to the nondiabetic groups were injected with vehicle (sodium citrate buffer), and rats assigned to the diabetic groups were injected with streptozotocin (50 mg/kg IP). Enalapril (10 mg/kg per day) was administered in the drinking water and coincided with the injection of vehicle or streptozotocin. Two to 3 months later, we examined responses of pial arterioles to nitric oxide synthase (NOS)-dependent agonists (acetylcholine and ADP) and a NOS-independent agonist (nitroglycerin). After these functional studies, we harvested cerebral microvessels for Western blot analysis of eNOS protein. Results - We found that acetylcholine- and ADP-induced dilatation of pial arterioles was impaired in diabetic compared with nondiabetic rats. In addition, while enalapril did not alter responses in nondiabetic rats, enalapril prevented diabetes-induced impairment of NOS-dependent vasodilatation. Furthermore, eNOS protein was higher in diabetic than in nondiabetic rats, and enalapril did not produce a further increase in eNOS protein in enalapril-treated diabetic rats compared with untreated diabetic rats. Conclusions - These results suggest that enalapril prevents cerebrovascular dysfunction in diabetic rats. We speculate that the protective role of enalapril may be independent of an alteration in eNOS protein in cerebral microvessels.

Original languageEnglish (US)
Pages (from-to)2698-2703
Number of pages6
JournalStroke
Volume34
Issue number11
DOIs
StatePublished - Nov 1 2003

Fingerprint

Enalapril
Arterioles
Nitric Oxide Synthase
Dilatation
Nitric Oxide Synthase Type III
Streptozocin
Microvessels
Proteins
Adenosine Diphosphate
Cholinergic Agonists
Nitroglycerin
Vasodilation
Drinking Water
Acetylcholine
Buffers
Western Blotting
Injections

Keywords

  • Acetylcholine
  • Adenosine
  • Angiotensin converting enzyme inhibitors
  • Brain
  • Nitric oxide
  • Nitroglycerin
  • Rats
  • Stroke

ASJC Scopus subject areas

  • Clinical Neurology
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialized Nursing

Cite this

Enalapril Prevents Impaired Nitric Oxide Synthase-Dependent Dilatation of Cerebral Arterioles in Diabetic Rats. / Trauernicht, Anna K.; Sun, Hong; Patel, Kaushik P; Mayhan, William.

In: Stroke, Vol. 34, No. 11, 01.11.2003, p. 2698-2703.

Research output: Contribution to journalArticle

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abstract = "Background and Purpose - Our goal was to identify the effects of chronic treatment with enalapril on cerebrovascular dysfunction and endothelial nitric oxide synthase (eNOS) protein in diabetic rats. Methods - Rats were assigned to 1 of 4 groups: nondiabetic, diabetic, nondiabetic/enalapril-treated, and diabetic/enalapril-treated groups. Rats assigned to the nondiabetic groups were injected with vehicle (sodium citrate buffer), and rats assigned to the diabetic groups were injected with streptozotocin (50 mg/kg IP). Enalapril (10 mg/kg per day) was administered in the drinking water and coincided with the injection of vehicle or streptozotocin. Two to 3 months later, we examined responses of pial arterioles to nitric oxide synthase (NOS)-dependent agonists (acetylcholine and ADP) and a NOS-independent agonist (nitroglycerin). After these functional studies, we harvested cerebral microvessels for Western blot analysis of eNOS protein. Results - We found that acetylcholine- and ADP-induced dilatation of pial arterioles was impaired in diabetic compared with nondiabetic rats. In addition, while enalapril did not alter responses in nondiabetic rats, enalapril prevented diabetes-induced impairment of NOS-dependent vasodilatation. Furthermore, eNOS protein was higher in diabetic than in nondiabetic rats, and enalapril did not produce a further increase in eNOS protein in enalapril-treated diabetic rats compared with untreated diabetic rats. Conclusions - These results suggest that enalapril prevents cerebrovascular dysfunction in diabetic rats. We speculate that the protective role of enalapril may be independent of an alteration in eNOS protein in cerebral microvessels.",
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AU - Sun, Hong

AU - Patel, Kaushik P

AU - Mayhan, William

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