Role of locus coeruleus in cerebral circulation and catecholamine metabolism

(1)蓝斑神经元活动响应高碳酸血症引起的大脑同动力变化。当吸入二氧化碳时，观察到蓝斑座同侧大脑皮质组织血流量显著增加。动作电位频率在CO2吸入开始后逐渐升高，在40秒内达到显著水平，最高可达147 (]SY.+-。[) 50秒时控制值的22%。停止吸入二氧化碳可使动作电位的频率逐渐恢复到控制水平。(2)蓝斑刺激引起的脑实质内血管收缩。受刺激侧脑血容量（CBV）在20Hz刺激开始后逐渐下降，在80秒时达到显著水平，最大值为-0.15 (]SY.+-。[) 140秒时控制值的0.05vol% （p<0.05）。对侧CBV也明显减少。50hz刺激也导致双侧CBV减少。(3)蓝斑改变蛛网膜下腔出血后脑实质内血管收缩活动。蓝斑刺激时CBV明显下降；比控制值（6.3 vol%）减少0.14 （]SY.+-）。[) 0.04 vol%在80秒（p<0.05）， 0.15 (] SY.+-。[) 0.03 vol%在120秒。停止刺激后，CBV逐渐恢复。(4)微透析技术分析儿茶酚胺。采用高压液相色谱法对微透析大脑皮层灌注液进行分析。我们成功地在同一样品中检测去甲肾上腺素，多巴胺，DOPAC， HVA，血清素和5-HIAA。

(1)Neuronal activities in locus ceruleus respond to cerebral homodynamic changes induced by hypercapnia.When CO2 inhalation was applied, the significant increase in blood flow of the cerebral cortical tissue ipsilateral to the locus ceruleus was observed. The frequency of action potentials showed a gradual increase following the start of CO2 inhalation and reached a significant level by 40 seconds with maximum of 147 (〕SY.+-.〔) 22 % of the control value at 50 seconds. The cessation of CO2 inhalation induced a gradual recovery in the frequency of the action potential to the control level.(2)Cerebral intraparenchymal vasoconstriction induced by locus ceruleus stimulation.Cerebral blood volume(CBV) on the stimulated side gradually decreased following the start of 20Hz stimulation and reached a significant level by 80 seconds with a maximum of -0.15 (〕SY.+-.〔) 0.05vol% of the control value(p<0.05) at 140 seconds. CBV on the contralateral side was also reduced significantly. 50 Hz stimulation also resulted in a reduction in CBV bilaterally.(3)Locus ceruleus alters intraparenchymal vasoconrtrictive activities following subarachnoid hemorrhage.The CBV deresased significantly during the stimulation of locus ceruleus ; the decrease from the control value(6.3 vol%) was 0.14 (〕SY.+-.〔) 0.04 vol% at 80 seconds(p<0.05), 0.15 (〕SY.+-.〔) 0.03 vol% at 120 seconds. After the cessation of the stimulation, CBV showed a gradual recovery.(4)Catecholamine analysis by microdialysis technique.Perfusate from the cerebral cortex using microdialysis was analyzed by using high pressure liquid chromatography. We succeed in detectig norepinephrine, dopamine, DOPAC, HVA, serotonin, and 5-HIAA in same sample.