多巴胺对内毒素孵育兔肺体动脉血管环张力的影响

目的 比较不同浓度多巴胺对大肠杆菌内毒素脂多糖(LPS)孵育的离体兔肺动脉、体动脉血管张力的影响.方法 选择6只雄性大耳白兔,制备离体肺动脉环和体动脉环各36个.把36个肺动脉环随机分为6组,测试不同浓度多巴胺(4×10-5、8×10-5、16×10-5 μmol/L)对正常肺动脉张力的影响(分别为PN-DOPA4、PN-DOPA8、PN-DOPA16组)及对LPS孵育后肺动脉张力的影响(分别为PL-DOPA4、PL-DOPA8、PL-DOPA16组).体动脉分组与肺动脉分组方法相同,包括正常组(SN-DOPA4、SN-DOPA8、SN-DOPA16)及内毒素组(SL-DOPA4、SL-DOPA8、SL-DOPA16).结果 ①多巴胺对PN-DOPA4及SN-DOPA4组中的血管环均有一定的舒张作用;对PN-DOPA8、PN-DOPA16、SN-DOPA8和SN-DOPA16组的血管环均有收缩作用,随着浓度的加大而升高.②LPS孵育后,多巴胺对PL-DOPA4和SL-DOPA4组血管环舒张作用消失,变为收缩[(22.60±6.68)%比-(2.25±0.58)%,(3.80±0.52)%比-(3.65±0.75)%,P<0.05和P<0.01],对PL-DOPA8组收缩幅度较PN-DOPA8组减少(14.52±0.59)%(P<0.05);对SL-DOPA8组收缩幅度较SN-DOPA8组增高(25.90±1.75)%(P<0.05);对PL-DOPA16组和SL-DOPA16组的张力无显著影响.③LPS孵育后,DOPA4组的肺动脉张力变化(PL/PN)较体动脉张力变化(SL/SN)明显(-10.90±5.06比-1.00±0.24,P<0.05);在DOPA8组SL/SN较明显(1.80±0.35比0.48±0.17,P<0.01).结论 低浓度的多巴胺对正常肺动脉及体动脉血管环有舒张作用;在LPS孵育后,低浓度的多巴胺对肺动脉及体动脉环的作用由舒张变为收缩,且对肺动脉环的张力变化影响最大;不同浓度的多巴胺对LPS孵育后的肺动脉及体动脉血管环均有收缩作用.

The comparison of the vasoactive effects of dopamine on isolated rabbit pulmonary and systemic arteries after incubation with lipopolysaccharide

Objective To compare the vasoactive effects of dopamine (DOPA) of different concentrations on isolated rabbit pulmonary and systemic arteries after incubation with lipopolysaccharide (LPS). Methods Six white male rabbits were used. Thirty-six pulmonary arterial rings and 36 systemic arterial rings were prepared. The 36 pulmonary arterial rings were divided into six groups to determine the effect of different concentrations of DOPA (4×10-5,8×10-5,16×10-5 μmol/L) on the tension of the normal pulmonary artery (PN-DOPA4, PN-DOPA8, PN-DOPA16 groups, respectively), and the tension of the pulmonary artery rings after being incubated with LPS (PL-DOPA4, PL-DOPA8, PL-DOPA16 groups, respectively). The 36 systemic arterial rings were also divided into six groups as the pulmonary arterial rings, including normal groups (SN-DOPA4, SN-DOPA8, SN-DOPA16) and LPS groups (SL-DOPA4, SL-DOPA8, SL-DOPA16). Results ① DOPA relaxed the arterial rings in PN-DOPA4 and SN-DOPA4 groups, while it produced contraction in PN-DOPA8, PN-DOPA16, SN-DOPA8 and SN-DOPA16 groups, and the contraction was more marked with the increase in concentration of DOPA. ② After preincubation with LPS, the relaxation property of DOPA in PL-DOPA4 and SL-DOPA4 groups was observed to be reversed to contraction (22.60±6.68)% vs.-(2.25±0.58)%, (3.80±0.52)% vs. -(3.65±0.75)%, P<0.05 and P<0.01]; the contraction response of DOPA in PL-DOPA8 group decreased compared with PN-DOPA8 group by (14.52±0.59)% (P<0.05), while increased by (25.90±1.75)% in SL-DOPA8 group compared with SN-DOPA8 group (P<0.05), and no response was observed in PL-DOPA16 and SL-DOPA16 groups. ③After reincubation with LPS, changes in pulmonary arterial tension (PL/PN) in DOPA4 group were more obvious than those in systemic arterial tension (SL/SN, -10.90±5.06 vs. -1.00±0.24, P<0.05), while the SL/SN in DOPA8 group were more obvious (1.80±0.35 vs. 0.48±0.17, P<0.01).Conclusion DOPA in low concentrations had the function of relaxation on the pulmonary arterial and systemic arterial rings. After the arterial rings are preincubated with LPS, the relaxation response of DOPA of low concentrations is changed to be vaso-contraction, and the changes in pulmonary arterial rings are most marked. DOPA of different concentrations all produce contraction effect on LPS-preincubated arterial rings.