【摘要】 以离体大鼠主动脉与肾动脉对去甲肾上腺素（ＮＥ）的收缩反应分别代表α１Ｂ与α１Ａ亚型肾上腺素受体（ＡＲ）激动时的生物学效应。血管经ＮＥ１０μｍｏｌ／Ｌ温育２ｈ后，α１－ＡＲ介导收缩效应的敏感性显著降低，其中α１Ｂ亚型ＡＲ的脱敏程度显著大于α１Ａ亚型ＡＲ。上述经ＮＥ温育的血管，在神经肽Ｙ（ＮＰＹ）０．５μｍｏｌ／Ｌ存在时，α１Ｂ亚型ＡＲ的脱敏程度显著减轻。ＮＥ收缩主动脉的两时相分析表明，脱敏时主要表现为相性收缩时间延长，收缩幅度降低，而紧张性收缩并无显著改变；在ＮＰＹ存在时上述相性收缩改变消失。提示α１Ｂ亚型ＡＲ脱敏的机制主要与细胞内Ｃａ２＋动员减慢减少有关。更多还原

【Abstract】 Vasoconstrictive responses to norepinephrine (NE) in isolated rat aorta and renal artery were respectively taken to represent the biological responses mediated by α1B and α1A subtype adrenoceptor (AR). After blood vessels were incubated with 10 μmol/L NE for 2 h, α1-AR mediated vasocontraction was desensitized significantly, α1B-AR being more marked than α1-AR. In the presence of 0. 5 μmol/L neuropeptide Y (NPY), desensitization of α1B-AR was attenuated significantly. In rat aorta the NE-mediated contraction comprised both phasic and tonic elements. After the incubation with NE, the phasic contraction period was prolonged but magnitude decreased, while no change was found for the tonic contraction. In the presence of NPY, the changes of phasic contraction caused by NE preincubation disappeared. It is suggested that retardation and deduction of intracellular Ca2+ release were involved in the mechanism for desensitization of α1B-AR.更多还原