In vivo visualization of subendocardial arteriolar response in renovascular hypertensive hearts.
Time-sequential responses to endothelium-dependent and -independent vasodilators and angiotensin-converting enzyme (ACE) inhibitors were studied in the subendocardial arterioles (Endo) of canine renovascular hypertension (HT) compared with subepicardial arterioles (Epi; both <120 microm) by charge-coupled device intravital microscope. Vascular responses to acetylcholine, papaverine, and cilazaprilat were compared between normotensive (NT) and HT dogs [4 wk and 12 wk of HT (4wHT and 12wHT)]. The acetylcholine-induced vasodilation of Endo in both 4wHT and 12wHT was smaller than that of NT (both P < 0.01 vs. 4wHT and 12wHT), and that of Epi was smaller than that of NT only in 12wHT (P < 0.05). The papaverine-induced vasodilation of Endo, but not Epi, was impaired only in 12wHT (both P < 0.01 vs. NT and 4wHT). Vasodilation by cilazaprilat remained unchanged at 4wHT and 12wHT in both Epi and Endo. In conclusion, at the early stage, the endothelium-dependent response of Endo was impaired, whereas at the later stage, the endothelium-dependent and -independent responses of Endo and the endothelium-dependent response of Epi were impaired. However, the vasodilatory responses to the ACE inhibitor were maintained in both Endo and Epi of HT.
Yada
Toyotaka
T
Department of Medical Engineering and Systems Cardiology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan. yada@me.kawasaki-m.ac.jp
Goto
Masami
M
Hiramatsu
Osamu
O
Tachibana
Hiroyuki
H
Toyota
Eiji
E
Nakamoto
Hiroshi
H
Ogasawara
Yasuo
Y
Matsuda
Hiroto
H
Arakawa
Koki
K
Hayashi
Koichi
K
Suzuki
Hiromichi
H
Kajiya
Fumihiko
F
D000109:Acetylcholine / Q000494:pharmacology; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000494:pharmacology; D000818:Animals; D001160:Arterioles / Q000502:physiology; D017315:Cilazapril / Q000031:analogs & derivatives* / Q000494:pharmacology; D003331:Coronary Vessels / Q000503:physiopathology*; D004285:Dogs; D004699:Endocardium / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000502:physiology; D005260:Female; D006977:Hypertension, Renal / Q000503:physiopathology*; D008297:Male; D008853:Microscopy / Q000379:methods; D010208:Papaverine / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000494:pharmacology
D000806:Angiotensin-Converting Enzyme Inhibitors; D014665:Vasodilator Agents; D017315:Cilazapril; D010208:Papaverine; D000109:Acetylcholine; C045980:cilazaprilat