Cholet N, Bonvento G, Seylaz J
Laboratoire de Recherches Cérébrovasculaires, CNRS, Université Paris, France.
Brain Res. 1996 Feb 5;708(1-2):197-200. doi: 10.1016/0006-8993(95)01387-3.
Whether nitric oxide (NO) mediates--or not--the local cerebral blood flow (CBF) increases occurring during functional brain activation is still a controversial issue. In the present study, we sought to determine whether neuronal NO synthase is involved in the cerebrovascular response to activation of the trigeminal pathway in the rat. Local CBF was measured using the autoradiographic [14C]iodoantipyrine technique in control alpha-chloralose anesthetized rats and 30 min following administration of 7-nitroindazole (7-NI), an inhibitor of the neuronal NO synthase. Unilateral whiskers stroking increased local CBF in all six regions of the trigeminal pathway. Under 7-NI, CBF was slightly decreased and the vasodilatatory response to whisker stimulation was unaltered in the four trigeminal nuclei studied. In contrast, no significant vasodilatation was noted in the ventral posteromedial thalamic nucleus and somatosensory cortex. These results suggest that the neuronal NO synthase mediates the hyperemia associated with somatosensory activation in second order relay stations but not in the site of termination of primary afferents.
一氧化氮（NO）是否介导——或者不介导——功能性脑激活过程中发生的局部脑血流量（CBF）增加仍是一个有争议的问题。在本研究中，我们试图确定神经元型一氧化氮合酶是否参与大鼠三叉神经通路激活后的脑血管反应。在对照的α-氯醛糖麻醉大鼠以及给予神经元型一氧化氮合酶抑制剂7-硝基吲唑（7-NI）30分钟后的大鼠中，使用放射自显影[14C]碘安替比林技术测量局部脑血流量。单侧触须刺激可增加三叉神经通路所有六个区域的局部脑血流量。在7-NI作用下，在所研究的四个三叉神经核中，脑血流量略有下降，对触须刺激的血管舒张反应未改变。相比之下，丘脑腹后内侧核和体感皮层未观察到明显的血管舒张。这些结果表明，神经元型一氧化氮合酶介导二级中继站中与体感激活相关的充血，但不介导初级传入神经终末部位的充血。
