大鼠窒息心脏骤停期间脑皮质β肾上腺素能受体和血中NO的变化

Changes of β-adrenoceptor in the cerebral cortex and blood nitric oxide during cardiac arrest in an asphyxiated rat model

目的研究心脏停搏期间脑皮质β肾上腺素能受体(β受体)的变化,检测心脏停搏前后血液NO浓度变化,探讨其意义。方法采用放射性配基结合分析方法,检测大鼠在窒息心脏停搏期间脑皮质β受体的变化。采用化学发光法,检测动物心脏停搏前后血中NO浓度的变化。将动物随机分为正常对照(A),手术对照(B),窒息10min(C)、20min(D)和30min(E)5组,每组6只。结果β受体数量D和E组分别与A、B、C组比较,差异极其显著(P<0.01)。各组间受体亲和力无明显变化。C组血中NO浓度与A、B组比较,差异极其显著(P<0.01)。结论在窒息心脏骤停早期,脑皮质β受体数量无明显变化,随着心脏停搏时间延长,其数量明显增加。心脏停搏以后,与心脏停搏前比较,血中NO浓度明显升高。

Objective Changes of β-adrenoceptor(β-AR)in the cerebral cortex and blood nitric oxide (NO)during asphyxiated cardiac arrest were investigated.Methods The β-AR of the membrane fraction of the cerebral cortex was analyzed by radioligand binding assay with the use of [3H]-DHA. The NO concentration was detected by the luminol chemiluminescence.The rats were divided into control(A),sham(B),asphyxiated 10 min(C), 20 min(D) and 30 min(E)group.Results The β-AR number in the cerebral cortex was (37.15±2.74)fmol/mg pr,(39.09±1.46)fmol/mg pr,(49.67±4.98)fmol/mg pr,(81.62±10.37)fmol/mg pr and (83.50±9.22) fmol/mg pr in the group A,B,C,D and E respectively.The β-AR number in group D and E was greater than that of group A,B and C respectively (P<0.01).The affinity(KD) of β-AR in the cerebral cortex among the groups didn't change.The NO concentration in blood in the group C (2 044.01±291.23) nmol/L was greater than that of the group A(1 156.12±258.16)nmol/L and B(1 299.17±269.44) nmol/L respectively(P<0.01).Conclusion The β-AR number in the rat cerebral cortex increased(up-regulation)after cardiac arrest with the cardiac arrest time prolonged.The NO in the blood increased significantly after cardiac arrest.