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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。
The contractile responses of noradrenalin (NE) to aortic and renal arteries in isolated rat represent the biological effects of α1B and α1A subtype adrenergic receptors (ARs), respectively. The sensitivity of α1-AR-mediated contractile effect was significantly decreased after 2 h of NE 10 μmol / L incubation. The desensitization degree of α1B subtype AR was significantly higher than that of α1A subtype AR. In the above-described NE-infused blood vessels, the degree of desensitization of α1B subtype AR was significantly reduced in the presence of neuropeptide Y (NPY) 0.5 μmol / L. Two-phase analysis of NE contraction aorta showed that desensitization mainly showed a prolongation of phase contractility, a decrease of contraction amplitude, and no significant change of tonic contraction. The phase shrinkage disappeared in the presence of NPY. Tip mechanism of α1B subtype AR desensitization is mainly related to the slowdown of intracellular Ca2 + mobilization.