Polymorphonuclear leukocytes (PMNs) functions in SHR, l-NAME- and DOCA/salt-induced hypertensive rats

Ohmori, Masami; Kitoh, Yasuhiko; Harada, Kazuhiro; Sugimoto, Koh‐ichi; Fujimura, Akio

doi:10.1097/00004872-200018060-00007

Cited by 11 publications

(14 citation statements)

References 20 publications

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“…Vascular tissues are also a rich source of ROS including H 2 O 2 . In SHR, polymorphonuclear leukocytes are more capable of producing superoxide than those from WKY rats (Ohmori et al, 2000), and vascular tissues including mesenteric arterioles have a higher level of ROS (Suzuki et al, 1995;Wu et al, 2002). Therefore, local H 2 O 2 might reach a level that can initiate K þ channel activation in the vasculature.…”

Section: Discussionmentioning

confidence: 99%

“…In the spontaneously hypertensive rats (SHR), a widely used animal model of human essential hypertension, a higher level of ROS and lipid peroxidation in mesenteric arterioles and myocardium was reported (Ito et al, 1992;Suzuki et al, 1995). Polymorphonuclear leukocytes of SHR produced more superoxide than that of WKY (Ohmori et al, 2000). In other hypertensive animal models, a higher production of ROS was found in deoxycorticosterone acetate-salt hypertensive rats, Dahl hypertensive rats, and in angiotensin II-or renovascular ligation-induced hypertensive rats (Rajagopalan et al, 1996;Swei et al, 1997;Harrison et al, 1999;Somers et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

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Vascular relaxation response to hydrogen peroxide is impaired in hypertension

Gao

Zhang

Hirota

et al. 2004

British J Pharmacology

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1 In phenylephrine (1 mM)-precontracted rat superior mesenteric arteries (MA), hydrogen peroxide (H 2 O 2 , 0.3 and 1 mM) caused a biphasic response: a transient contraction followed by a relaxation. In the presence of thromboxane A 2 /prostaglandin H 2 (TP) receptor antagonist (SQ 29548), the contractile component of the biphasic response was abolished. The relaxation response to H 2 O 2 was smaller in spontaneously hypertensive rats (SHR) when compared with normotensive Wistar-Kyoto rats (WKY). 2 The mechanisms for the attenuated relaxation to H 2 O 2 in the SHR were studied. KCl (40 mM) prevented the relaxation response. Calcium-dependent K þ channel (K Ca ) blockers (tetraethylammonium chloride, TEA; iberiotoxin, and charybdotoxin) showed a greater inhibition of H 2 O 2 relaxation in SHR than in WKY, whereas voltage-dependent K þ -channel (K v ) blocker 4-aminopyridine was more effective in inhibiting the relaxation in WKY than in SHR. 3 H 2 O 2 (1 mM) greatly enhanced the frequency and intensity of the spontaneous transient outward K þ currents in SHR MA, and the effects of H 2 O 2 were inhibited by iberiotoxin, while in WKY MA the K þ currents induced by H 2 O 2 were mainly of the K v type. The consequence of the activation of different types of K þ channel was that the net increase in mean outward K þ current density in response to H 2 O 2 was smaller in SHR than in WKY, which may account for the attenuated relaxation response to H 2 O 2 in the SHR. 4 The contractile responses of MA to TEA, iberiotoxin, and charybdotoxin were greater in SHR than in WKY. 5 In summary, an attenuated relaxation response to H 2 O 2 was found in SHR MA when compared to WKY. In contrast to the activation of K v channels in WKY, H 2 O 2 markedly enhanced K Ca activity in SHR, resulting in an attenuation of the increase in mean outward K þ current density in response to H 2 O 2 . These results suggest that alteration in K þ channel activation by reactive oxygen species may play a role in the development of hypertension in SHR.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Vascular relaxation response to hydrogen peroxide is impaired in hypertension

Gao

Zhang

Hirota

et al. 2004

British J Pharmacology

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show abstract

“…Three types of hypertensive rat models 10 were used in this study. Male SHR/Izm (SHR) and WKY/Izm (WKY, most appropriate control animal of SHR), and Wistar rats (Japan SLC Ltd., Sizuoka, Japan) were maintained under a specific pathogen-free room with a 12-h light/dark cycle (7 AM light on and 7 PM light off) in the animal center of Jichi Medical School.…”

Section: Hypertensive and Their Control Ratsmentioning

confidence: 99%

“…10 Average of three stable systolic BP and pulse rate values were regarded as representative BP and pulse rate, respectively.…”

Section: Measurements Of Systolic Bp and Pulse Ratementioning

confidence: 99%

“…8 -10 In a previous study, we also found that the PMNs functions did not elevate in N-nitro-L-arginine methyl ester (L-NAME)-treated or deoxycorticosterone acetate (DOCA)/salt-treated rats. 10 Ischemia-reperfusion (I/R) injury is induced and modified by several factors including nitric oxide-endothelin imbalance and elevations of inflammatory cytokines (TNF-␣ and IL-6), free radicals, and phagocytes (macrophages, monocytes, and PMNs). [11][12][13] The removal of PMNs from blood circulation and treatment with PMNs antibody are shown to ameliorate hepatic damages induced by I/R, which indicate that PMNs are partially involved in the initiation and development of the injuries.…”

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confidence: 99%

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