Perivascular innervation of penetrating brain parenchymal arterioles
Perivascular innervation of penetrating brain parenchymal arterioles
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DOI：
10.1097/00005344-200407000-00001
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发表时间：
2004-07-01
影响因子：
3
通讯作者：
Vitullo, L
中科院分区：
文献类型：
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作者：
Cipolla, MJ;Li, R;Vitullo, L
我们通过比较生肌活性和对神经递质的反应性，研究了脑软膜动脉的功能异质性，这些动脉是外神经支配的，而穿透脑实质小动脉（PA）是内在神经支配的。从雄性Wistar大鼠分离出软脑膜大脑中动脉（MCA，n = 6）和PA（n = 6）分支的MCA和穿透脑组织，并在体外研究加压条件下对5-羟色胺（5-HT），去甲肾上腺素（NA）和吲哚内酰胺-V（IL-V），蛋白激酶C（PKC）激动剂的反应性。在来自相同位置的单独一组血管中（n = 12），在蛋白基因产物9.5（PGP 9.5）染色后测定血管周围神经密度。PA显着小于MCA，并具有更大的肌张力在所有的压力研究。MCA对5-HT和NA都有浓度依赖性收缩反应，而PA对这两种神经递质几乎没有反应。MCA与PA在最大浓度下对5-HT和NA的收缩百分比分别为：31 +/- 6%与1.0 +/- 1.0%和13 +/- 5%与2.6 +/- 1.8%（P < 0.01）。然而，两种类型的血管收缩对IL-V激活PKC的反应性相似（41 +/- 4%对37 +/-7%，ns）。血管周围神经密度与反应性相关，使得MCA外膜内的静脉曲张纤维密集地支配;然而，PA具有非常少或没有外膜纤维。对神经递质的不同反应表明脑循环中存在显著的异质性。看来，在PA中，占主导地位的血管收缩刺激是内在肌源性张力，神经递质和内在神经支配的作用超出了控制CBF。
We investigated the functional heterogeneity of cerebral pial arteries that are extrinsically innervated versus penetrating brain parenchymal arterioles (PA) that are intrinsically innervated by comparing myogenic activity and reactivity to neurotransmitter. Pial middle cerebral arteries (MCA, n = 6) and PA (n = 6) that branched off the MCA and penetrated the brain tissue were isolated from male Wistar rats and studied in vitro under pressurized conditions for reactivity to serotonin (5-hydroxytryptamine, 5-HT), noradrenaline (NA), and indolactam-V (IL-V), a protein kinase C (PKC) agonist. In a separate group of vessels from the same locations (n = 12), perivascular nerve density was determined after staining for protein gene product 9.5 (PGP 9.5). PAs were significantly smaller than MCAs, and possessed greater myogenic tone at all pressures studied. MCAs reacted to both 5-HT and NA with concentration-dependent contraction, however, PA had little to no response to either neurotransmitter. The percent constriction to 5-HT and NA for MCA versus PA at the maximum concentration was: 31 +/- 6% versus 1.0 +/- 1.0% and 13 +/- 5% versus 2.6 +/- 1.8% (P < 0.01). However, both types of vessels contracted with similar reactivity to PKC activation with IL-V (41 +/- 4% versus 37 +/- 7%, ns). Perivascular nerve density correlated with reactivity such that MCAs were densely innervated with varicose fibers within the adventitia; however, PA had very few or no adventitial fibers. The differential response to neurotransmitter suggests that there is significant heterogeneity in the cerebral circulation. It appears that in PA, the dominant vasoconstricting stimulus is intrinsic myogenic tone and that the role of neurotransmitter and intrinsic innervation is beyond that of controlling CBF.