摘要
目的观察20-羟廿碳四烯酸（20-HETE）在低碳酸血症犬脑血管收缩中的作用,探讨低碳酸血症时脑动脉收缩的机制。方法11条健康成年杂种犬,麻醉下开颅,在PETCO2 40 mm Hg时、过度通气致PETCO2 20 mm Hg时、恢复正常通气PETCO2加mm Hg后加入20-HETE阻断剂17-octadecynoic acid（17-ODYA）并过度通气致PETCO2 20 mm Hg时、加入外源性20-HETE并过度通气致PETCO2 20 mm Hg时,分别于各状态1、5、15、30、60min时测量大脑中动脉、小动脉的直径。结果整个实验过程体温和血液动力学维持稳定。与PETCO2 40 mm Hg时相比,过度通气致PETCO2 20 mm Hg时小动脉直径缩小（P＜0．05）;17-ODYA局部给药并过度通气致PETCO 20 mm Hg时小动脉直径差异无统计学意义（P＞0．05）;外源性20-HETE局部给药并过度通气时小动脉直径缩小（P＜0．05）;在上述各种状态时大脑中动脉直径均无明显变化（P＞0．05）。结论犬低碳酸血症时,20-HETE可能是诱发脑小动脉收缩的机制之一。
Objective To investigate the role 20-hydroxyeicosatetraenoic acid （20-HETE） plays in the cerebral vasoconstriction induced by hypocapnia. Methods Eleven mongrel dogs aged 2-3 yr weighing 14-16 kg were selected, and anesthesia was induced with pentobarbital, fentanyl and vecuronium, and maintained with inhalation of isoflurane. After tracheal intubation dogs were mechanically ventilated with pure oxygen. PETCO2 was maintained at 40 mm Hg. Femoral artery and vein were cannulated for fluid administration, BP monitoring and blood sampling. ECG was continuously monitored. Rectal temperature was maintained at 38.5-39.5℃. A hole of 4 cm in diameter was made in the skull midway between left eye and ear canal. The dura mater was opened and middle cerebral artery （MCA） and its branch were exposed and kept moist by dripping with artificial cerebral spinal fluid. A special microscope was used to measure the diameter of MCA and the branch. The following steps were followed： （A） the baseline values of BP, HR and diameter of MCA and its branch were recorded; （B） PETCO2 was reduced to 20 mm Hg by hyperventilation, HR, BP and diameter of MCA and the branch were recorded at 1, 5, 15, 30 and 60 minof hypecapnia; （C） 17-octadecynoic （17-ODYA） （a 20-HETE blocker） 1 μmol/L was dripping onto MCA and its branch at 1 ml/min and the changes in BP, HR and diameter of MCA and the branch were observed for 60 min, then （D） 20-HETE 3 μmol/L was dripped onto MCA at 1 ml/min and observation was made for 60 min. Results There was no significant change in BP, HR and diameter of MCA throughout the 4 steps of the experiment. The arteriole （the branch of MCA） was significantly constricted during hypocapnia （PETCO2 = 20 mm Hg） as compared to the baseline. The arteriole did not constrict during hypocapnia in the presence of 17-ODYA, but constricted again when 20-HETE was added. Conclusion 20-HETE is involved in the mechanism of vasoconstriction of cerebral arterioles induced by hypocapnia in dogs.
出处
《中华麻醉学杂志》
CAS
CSCD
北大核心
2007年第3期278-281,共4页
Chinese Journal of Anesthesiology
基金
黑龙江省自然科学基金项目（D0316）
