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目的应用氢清除法测定局部脑组织血流（ｒＣＢＦ）及观测软脑膜血管微循环，探讨电刺激兔中缝背核（ＤＲＮ）对脑皮质微血流的影响及其机理。方法选用健康家兔３３只、随机分为四组。单纯刺激组（ｎ＝１５）．单纯刺激ＤＲＮ后，连续观察３０ｍｉｎ内局部脑组织血流（ｒＣＢＦ，ｎ＝１０）或软脑膜血管微循环的变化（ｎ＝５）。尼莫地平组（ｎ＝６），在电刺激ＤＲＮ之前先静注尼莫地平（５μｇ／ｋｇ）。切断颈交感神经组（ｎ＝６）。切断两侧预交感神经后、再刺激 ＤＲＮ，破坏兰斑核组（ＬＣ， ｎ＝６），破坏同侧兰斑核后再刺激ＤＲＮ，分别观察ｒＣＢＦ的变化。结果电刺激ＤＲＮ后脑皮质ｒＣＢＦ减少４４．２％（Ｐ＜０．０１），软脑膜微动脉管径缩小，血流速度减慢，血流量减少，作用持续 １５ｍｉｎ。而尼莫地平可取消其作用。切断颈交感神经或破坏ＬＣ后再刺激ＤＲＮ，ｒＣＢＦ分别减少１５．８％和１６．６％（Ｐ＜０．０５）。ｒＣＢＦ降低幅度均小于正常动物。电刺激ＤＲＮ对半球脑血流动力学无显著影响。结论电刺激中缝背核可致兔脑皮质微动脉收缩，局部组织血流减少、其途径有二；一是中枢性５－ＨＴ能神经元兴奋引起的直接缩血管作用；二是通过激活中枢和外周去甲肾上腺素能神经系统引起
Objective To determine the local cerebral blood flow (rCBF) and observe the pia mater microcirculation by hydrogen scavenging, and to explore the effect and mechanism of electrical stimulation of dorsal raphe nucleus (DRN) on cerebral microcirculation. Methods 33 healthy rabbits were randomly divided into four groups. Stimulation alone group (n = 15). After stimulation of DRN, the changes of local cerebral blood flow (rCBF, n = 10) or pia mater microcirculation within 30 min were observed continuously (n = 5). The nimodipine group (n = 6) received nimodipine (5 μg / kg) intravenously before electrical stimulation of DRN. Cervical sympathetic ganglia were cut (n = 6). After cutting off the pre-sympathetic nerves on both sides, stimulating DRN, destroying the blue plaque group (LC, n = 6), destroying the ipsilateral plaque and stimulating the DRN again to observe the changes of rCBF. Results The rCBF of cerebral cortex decreased 44.2% (P <0.01) after electrical stimulation of DRN. The diameter of pia mater microvessel decreased, blood flow decreased and blood flow decreased for 15 minutes. And nimodipine can cancel its role. The ratio of rCBF decreased 15.8% and 16.6% (P <0.05) respectively after cutting off the cervical sympathetic nerve or destroying the LC. rCBF decreased less than normal animals. Electrical stimulation of DRN had no significant effect on hemodynamics of hemispheres. Conclusions Electrical dorsal raphe nucleus can induce the contraction of arteriolar microvessels in the cerebral cortex and decrease the blood flow in the local tissues. There are two routes: one is the direct vasoconstriction induced by the excitement of the central 5-HT neurons; the other is through activation of the central and Peripheral noradrenergic nervous system caused