Impaired response of perforating arteries to hypercapnia in chronic hyperglycemia.
Diabetes mellitus increases the risk of cerebrovascular disease, the effects of hypercapnia on CBF (cerebral blood flow) and cerebrovascular reactivity during diabetes are still inconsistent. Here, we have established a new microangiographic technique using synchrotron radiation (SPring-8, Japan), which enabled us to visualize rat cerebral vessels with high spatial resolution in real time. The goal of the study presented here was to identify the effects of chronic hyperglycemia on hypercapnia-induced vascular responses (endothelium-dependent vasodilatation) and nitric oxide (NO) donor- induced vascular responses (endothelium-independent) of perforating arteries and of the deeply located large cerebral arteries. We found a significant vasodilatation of rat perforating arteries after hypercapnia with a maximum diameter of approximately 140% of baseline in normal Wistar rats. Chronic hyperglycemia impaired vasodilatation of perforating arteries in genetically diabetic GK rats. SNP (sodium nitroprusside) caused a similar vasodilatation of perforating vessels in normal and chronic hyperglycemia, indicating that endothelium-dependent vasodilatation of perforating arteries may be specifically impaired in chronic hyperglycemia. Possible impairment of endothelium-dependent vasodilatation in perforating vessels during chronic hyperglycemia may cause decreased vascular reserve capacity of perforating artery, resulting in the increased ischemic insults and cerebrovascular diseases in diabetes.
Oizumi
Ximena-Sayuri
XS
Division of Internal and Geriatric Medicine, Kobe University Graduate School of Medicine, Japan.
Akisaki
Taichi
T
Kouta
Yoshiyuki
Y
Song
Xiu Z
XZ
Takata
Toshihiro
T
Kondoh
Takeshi
T
Umetani
Keiji
K
Hirano
Masatsugu
M
Yamasaki
Katsuhito
K
Kohmura
Eiji
E
Yokono
Koichi
K
Sakurai
Takashi
T
D000818:Animals; D001921:Brain / Q000098:blood supply; D002245:Carbon Dioxide / Q000008:administration & dosage; D002536:Cerebral Arteries / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000503:physiopathology; D006935:Hypercapnia / Q000503:physiopathology*; D006943:Hyperglycemia / Q000503:physiopathology*; D008297:Male; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D014664:Vasodilation / Q000187:drug effects
D020030:Nitric Oxide Donors; D002245:Carbon Dioxide; D009599:Nitroprusside