一氧化氮和内皮衍生超极化因子对大鼠离体肠系膜动脉床中激动剂刺激的内皮依赖性舒张相对贡献的性别差异。

Sex differences in the relative contributions of nitric oxide and EDHF to agonist-stimulated endothelium-dependent relaxations in the rat isolated mesenteric arterial bed.

作者信息

McCulloch A I, Randall M D

机构信息

Department of Physiology and Pharmacology, University of Nottingham Medical School, Queen's Medical Centre.

出版信息

Br J Pharmacol. 1998 Apr;123(8):1700-6. doi: 10.1038/sj.bjp.0701781.

DOI:10.1038/sj.bjp.0701781

PMID:9605578

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1565335/

Abstract

We have used the isolated, buffer-perfused, superior mesenteric arterial bed of male and female rats to assess the relative contributions of nitric oxide (NO) and the endothelium-derived hyperpolarizing factor (EDHF) to endothelium-dependent relaxations to carbachol. 2. Carbachol caused dose-related relaxations of methoxamine-induced tone in mesenteric vascular beds from male rats described by an ED50(M) of 0.43+/-0.15 nmol and a maximum relaxation (Rmax(M) of 89.6+/-1.2% (n=28) which were not significantly different from those observed in mesenteries from female rats (ED50(F)=0.72+/-0.19 nmol and Rax(F)=90.7+/-0.9%; n=22). 3. In the males, the addition of 100 microM NG-nitro-L-arginine methyl ester (L-NAME) caused the dose-response curve to carbachol to be significantly (P<0.001) shifted to the right 15 fold (ED50(M)=6.45+/-3.53 nmol) and significantly (P<0.01) reduced Rmax(M) (79.7+/-2.8%, n=13). By contrast, L-NAME had no effect on vasorelaxation to carbachol in mesenteries from female rats (ED50(f)= 0.89+/-0.19 nmol, Rmax(F)=86.9+/-2.3%, n=9). 4. Raising tone with 60 mM KCl significantly reduced the maximum relaxation to carbachol in mesenteries from male rats 2 fold (Rmax(M)=40.3+/-9.2%, n=4; P<0.001) and female rats by 1.5 fold (Rmax(F)=55.3+/-3.3%, n=6; P<0.001), compared with methoxamine-induced tone. The potency of carbachol was also significantly reduced 1.2 fold in preparations from males (ED50(M)=0.87+/-0.26 nmol; P<0.01) but not the females (ED50(F)=4.04+/-1.46 nmol). In the presence of both 60 mM KCl and L-NAME, the vasorelaxation to carbachol was completely abolished in mesenteries from both groups. 5. The cannabinoid receptor antagonist SR141716A (1 microM), which is also a putative EDHF antagonist, had no significant effect on the responses to carbachol in mesenteries from males or females (ED50(M)=1.41+/-0.74 nmol, Rmax(M)=89.4+/-2.5%, n=7; ED50(F)=2.17+/-0.95 nmol, Rmax(F)=89.9+/-1.8%, n=9). In mesenteries from male rats, in the presence of 100 microM L-NAME, SR141716A significantly (P<0.05) shifted the dose-response curve to carbachol 8 fold further to the right than that seen in the presence of L-NAME alone (ED50(M)= 53.8+/-36.8 nmol) without affecting Rmax(M) (72.4+/-4.8%, n=10). In mesenteries from female rats, the combined presence of L-NAME and SR141716A, significantly (P < 0.01) shifted the dose-response curve to carbachol 7.5 fold, (ED50(F)=6.66+/-2.46 nmol), as compared to L-NAME alone and significantly (P<0.001) decreased Rmax(F) (70.1+/-5.5%, n=8). 6. Vasorelaxations to the nitric oxide donor sodium nitroprusside (SNP), to the endogenous cannabinoid, anandamide (a putative EDHF) and to the ATP-sensitive potassium channel activator, levcromakalim, did not differ significantly between male and female mesenteric vascular beds. 7. The continuous presence of sodium nitroprusside (SNP; 20-60 nM) had no effect on vasorelaxation to carbachol in mesenteries from either males or females. In the presence of L-NAME, SNP significantly (P<0.05) reduced the potency of carbachol 6 fold, without affecting the maximal relaxation in mesenteries from male rats (ED50(M)=40.9+/-19.6 nmol, Rmax(M)=79.4+/-2.5%, n=11). Similarly in mesenteries from female rats, the ED50(F) was also significantly (P<0.01) increased 7 fold (6.24+/-2.02 nmol), while the Rmax(F) was unaffected (81.9+/-11.0%; n=4). 8 The results of the present investigation demonstrate that the relative contributions of agonist-stimulated NO and EDHF to endothelium-dependent relaxations in the rat isolated mesenteric arterial bed, differ between males and females. Specifically, although both NO and EDHF appear to contribute towards endothelium-dependent relaxations in males and females, blockade of NO synthesis alone has no effect in the female. This suggests that EDHF is functionally more important in females; one possible explanation for this is that in the absence of NO, the recently identified ability of EDHF to compensate for the loss of NO, is functio

摘要

我们使用了雄性和雌性大鼠分离的、经缓冲液灌注的肠系膜上动脉床，以评估一氧化氮（NO）和内皮衍生超极化因子（EDHF）对卡巴胆碱引起的内皮依赖性舒张的相对贡献。2. 卡巴胆碱使雄性大鼠肠系膜血管床中去氧肾上腺素诱导的张力产生剂量依赖性舒张，其半数有效剂量（ED50(M)）为0.43±0.15 nmol，最大舒张率（Rmax(M)）为89.6±1.2%（n = 28），与雌性大鼠肠系膜中的情况无显著差异（ED50(F)=0.72±0.19 nmol，Rmax(F)=90.7±0.9%；n = 22）。3. 在雄性大鼠中，加入100 μM NG-硝基-L-精氨酸甲酯（L-NAME）使卡巴胆碱的剂量反应曲线显著（P<0.001）右移15倍（ED50(M)=6.45±3.53 nmol），并显著（P<0.01）降低Rmax(M)（79.7±2.8%，n = 13）。相比之下，L-NAME对雌性大鼠肠系膜中卡巴胆碱引起的血管舒张无影响（ED50(f)=0.89±0.19 nmol，Rmax(F)=86.9±2.3%，n = 9）。4. 使用60 mM KCl升高张力可使雄性大鼠肠系膜中卡巴胆碱的最大舒张率显著降低2倍（Rmax(M)=40.3±9.2%，n = 4；P<0.001），雌性大鼠降低1.5倍（Rmax(F)=55.3±3.3%，n = 6；P<0.001），与去氧肾上腺素诱导的张力相比。卡巴胆碱的效力在雄性大鼠制备物中也显著降低1.2倍（ED50(M)=0.87±0.26 nmol；P<0.01），但在雌性大鼠中未降低（ED�0(F)=[4.04±1.46 nmol]）。在同时存在60 mM KCl和L-NAME的情况下，两组肠系膜中对卡巴胆碱的血管舒张均完全被消除。5. 大麻素受体拮抗剂SR141716A（1 μM），它也是一种假定的EDHF拮抗剂，对雄性或雌性大鼠肠系膜中对卡巴胆碱的反应无显著影响（ED50(M)=1.41±0.74 nmol，Rmax(M)=89.4±2.5%，n = 7；ED50(F)=2.17±0.95 nmol，Rmax(F)=89.9±1.8%，n = 9）。在雄性大鼠肠系膜中，在存在100 μM L-NAME的情况下，SR141716A使卡巴胆碱的剂量反应曲线显著（P<0.05）进一步右移8倍，比仅存在L-NAME时（ED50(M)=53.8±[36.8 nmol]）更显著，且不影响Rmax(M)（72.4±4.8%，n = 10）。在雌性大鼠肠系膜中，L-NAME和SR141716A共同存在时，与仅存在L-NAME相比，卡巴胆碱的剂量反应曲线显著（P<0.01）右移7.5倍（ED50(F)=6.66±2.46 nmol），且显著（P<0.001）降低Rmax(F)（70.1±5.5%，n = 8）。6. 对一氧化氮供体硝普钠（SNP）、内源性大麻素、花生四烯乙醇胺（一种假定的EDHF）以及ATP敏感性钾通道激活剂利克罗卡利姆的血管舒张反应，在雄性和雌性肠系膜血管床之间无显著差异。7. 持续存在硝普钠（SNP；20 - 60 nM）对雄性或雌性大鼠肠系膜中卡巴胆碱引起的血管舒张无影响。在存在L-NAME的情况下，SNP显著（P<0.05）降低卡巴胆碱的效力6倍，且不影响雄性大鼠肠系膜中的最大舒张率（ED50(M)=40.9±19.6 nmol，Rmax(M)=79.4±2.5%，n = 11）。同样，在雌性大鼠肠系膜中，ED50(F)也显著（P<0.01）升高7倍（6.24±2.02 nmol），而Rmax(F)未受影响（81.9±11.0%；n = 4）。8. 本研究结果表明，在大鼠离体肠系膜动脉床中，激动剂刺激产生的NO和EDHF对内皮依赖性舒张的相对贡献在雄性和雌性之间存在差异。具体而言，尽管NO和EDHF似乎在雄性和雌性中均对内皮依赖性舒张有贡献，但单独阻断NO合成对雌性无影响。这表明EDHF在雌性中功能上更重要；对此的一种可能解释是，在没有NO的情况下，最近发现的EDHF补偿NO缺失的能力发挥了作用。