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研究α_1肾上腺素受体(α_1-AR)不同亚型之间激动剂诱导的减敏和利血平化诱导的增敏过程的差别.方法:采用大鼠离体血管收缩功能实验,观察主动脉、肾动脉和肠系膜动脉在CEC 100 μmol·L~(-1)温育30 min后,NE介导的累积浓度收缩曲线(CCRC)的变化,以观察不同血管的亚型差异;在观察减敏时,血管用NE 10 μmol·L~(-1)预温育1 h,洗出后做NE的CCRC;在观察增敏的差异时,大鼠用reserpine 4 mg·kg~(-1)ip 48 h后,观察NE诱导的CCRC的变化.本实验在灌流液中含yohimbine和propranolol以阻断α_2-和β-AR,这样NE仅激活α_1-AR.结果:CEC 100 μmol·L~(-1)温育30 min,使NE介导的主动脉,肠系膜动脉的最大收缩分别降低82.5±3.0％和54.2±9.5％,而对肾动脉则无影响,再次肯定主动脉主要含α_(1B)-AR,肾动脉主要含α_(1A)-AR,肠系膜动脉兼含两种亚型.NE 10 μmol·L~(-1)温育1 h后,NE介导的主动脉,肾动脉和肠系膜动脉收缩的敏感性降低,EC_(50)分别增加了14.4±5.9,1.8±0.8和7.3±1.8倍;而在利血平化大鼠NE介导肾动脉收缩反应增加了56％,主动脉则无变化.结论:α_(1B)-AR亚型介导的反应易发生减敏;a_(1A)-AR亚型介导的反应易发生增敏.
To investigate the difference of agonist-induced desensitization and reserpine-induced sensitization between different subtypes of α 1 -adrenoceptor (α 1-AR) .Methods: Rat vasoconstriction was used to observe the effects of aorta, Renal artery and mesenteric artery were incubated with CEC 100 μmol·L -1 for 30 min to observe the changes of CCRC in different groups. , And the blood vessels were preincubated with NE 10 μmol·L -1 for 1 h and then washed out for NE CCRC. When the difference in sensitization was observed, rats were treated with reserpine 4 mg · kg -1 ip 48 h, the change of CCRC induced by NE was observed.In this experiment, yohimbine and propranolol were contained in the perfusate to block α_2- and β-AR, so that NE only activated α_1-AR.Results: CEC 100 μmol·L -1 ) For 30 min, the maximal contractions of NE-mediated aorta and mesenteric artery were reduced by 82.5 ± 3.0% and 54.2 ± 9.5%, respectively, but not to the renal artery. AR, the renal arteries mainly contain α_ (1A) -AR, the mesenteric artery and the two subtypes, NE-mediated aorta, renal artery and mesenteric artery after 1 h incubation with NE 10 μmol·L -1 Systolic sensitivity decreased , And EC 50 increased by 14.4 ± 5.9, 1.8 ± 0.8 and 7.3 ± 1.8 times, respectively, while NE-mediated renal artery contractile response increased by 56% in reserpine-deprived rats and no changes in aorta.Conclusion: (1B) -AR subtype-mediated reaction prone to desensitization; a_ (1A) -AR subtype-mediated reaction susceptible to sensitization.