The role of the glia limitans in ADP-induced pial arteriolar relaxation in intact and ovariectomized female rats.
The role of the glia limitans in ADP-induced pial arteriolar relaxation in intact and ovariectomized female rats.
复制标题
胶质细胞限制在 ADP 诱导的完整和卵巢切除雌性大鼠软脑膜小动脉松弛中的作用。
DOI：
10.1152/ajpheart.00727.2004
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Pelligrino,DaleA
中科院分区：
文献类型：
--
作者：
Xu,Hao-Liang;Ye,Shuhua;Baughman,VernaL;Feinstein,DouglasL;Pelligrino,DaleA
We examined whether the glia limitans (GL) influences pial arteriolar relaxation elicited in vivo by the purinergic (P2Y1receptor) agonist ADP in female rats, and whether that influence is altered in ovariectomized (Ovx) females. A validated model for GL injury was used, topical application of the gliotoxinl-α-aminoadipic acid (l-αAAA), 24 h before the study. In both intact and Ovx females,l-αAAA had no effect on responses to the NO donor,S-nitroso-N-acetyl penicillamine, but ADP-induced pial arteriolar dilations were significantly reduced (by 33–90%), compared with vehicle-treated controls. WhenNG-nitro-l-arginine (l-NNA) was administered tol-αAAA-treated rats, the ADP response was virtually lost in intact females, but no further reductions were observed in the Ovx rats. On the other hand, inl-αAAA-treated Ovx females, when the gap junction blocker, Gap 27, was subsequently added to the suffusate, ADP reactivity fell to very low levels. In vehicle-treated control rats,l-NNA and Gap 27 reduced ADP reactivity by ∼50% in intact and Ovx females, respectively. An earlier study indicated that the endothelium was a key site of influence forl-NNA (intact) and Gap 27 (Ovx). Thus present and previous results imply that the ADP response in pial arterioles represents the additive actions of an endothelial and a GL component. That supposition was confirmed in the present study by the finding that combining endothelial and GL injury produced an essentially complete loss of ADP reactivity in both intact and Ovx females. Finally, topical application of the selective P2Y1antagonist, MRS-2179, was associated with a nearly complete suppression of the ADP response in both intact and Ovx females. These results suggest that1) ADP-induced pial arteriolar dilation involves additive contributions from P2Y1receptors present in both vascular endothelium and the GL;2) the influence of the GL component is not altered by ovariectomy; and3) the gap junction-dependent component of the ADP response in Ovx females is unlikely to include the GL and probably resides in the vessels themselves.
