Impaired nitric oxide-independent dilation of renal afferent arterioles in spontaneously hypertensive rats

Koichi Hayashi, Hiroto Matsuda, Takahiko Nagahama, Keiji Fujiwara, Yuri Ozawa, Eiji Kubota, Masanori Honda, Hirobumi Tokuyama, Takao Saruta

研究成果: Article査読

18 被引用数 (Scopus)

抄録

Sustained hypertension alters vasomotor regulation in various vascular beds. We studied whether nitric oxide (NO) dependent and NO-independent vasodilator mechanisms are altered in renal microvessels in hypertension. To directly visualize the renal microcirculation, the isolated perfused hydronephrotic rat kidney model was used. After pretreatment with indomethacin (100 μmol/l), afferent arterioles were constricted by norepinephrine (NE) or by increasing renal arterial pressure (i.e., myogenic constriction; from 80 to 180 mmHg). Acetylcholine (ACH) was then added, and the renal microvascular response was assessed by computer-assisted video image analysis. A similar protocol was conducted in the presence of nitro-L-arginine methylester (L-NAME; 100 μmol/l). During NE constriction, ACH caused dose-dependent and sustained vasodilation of the afferent arteriole, similar in magnitude in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR). In the presence of L-NAME, ACH (0.01-1 μmol/l) elicited only transient dilation, and the degree of vasodilation was very low in SHR. During myogenic constriction, afferent arterioles from WKY and SHR kidneys responded to ACH with only transient vasodilation, which was unaffected by NO inhibition; the transient vasodilative responses elicited by ACH (0.1-1 μmol/l) were smaller in SHR than in WKY. In conclusion, ACH has both sustained and transient vasodilative effects on the afferent arteriole. Sustained vasodilation is attributed to NO generation, which is similar in WKY and SHR. In contrast, transient vasodilation, mediated by NO-independent vasodilator factors, is impaired in SHR. Deranged vasodilatory mechanisms in hypertension may disturb the renal microcirculation, which may result in renal injury.

本文言語English
ページ(範囲)31-37
ページ数7
ジャーナルHypertension Research - Clinical and Experimental
22
1
DOI
出版ステータスPublished - 1999 3月

ASJC Scopus subject areas

  • 内科学
  • 生理学
  • 循環器および心血管医学

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