Macia R A, Matthews W D, Lafferty J, DeMarinis R M
Naunyn Schmiedebergs Arch Pharmacol. 1984 Apr;325(4):306-9. doi: 10.1007/BF00504373.
The postsynaptic alpha-adrenoceptors in the isolated rat aorta have been characterized according to the sensitivity of the tissue to selective alpha 1- and alpha 2-adrenoceptor agonists and antagonists. The potency (-log EC50) order of the non-selective alpha-agonist norepinephrine and relatively selective agonists was as follows: norepinephrine (alpha 1 = alpha 2; 7.30); clonidine (alpha 2 greater than alpha 1; 7.01); phenylephrine (alpha 1 greater than alpha 2; 6.99), SK & F 89748--A (alpha 1 greater than alpha 2; 6.65); BHT-920 (alpha 2 much greater than alpha 1; 5.56) and M-7 (alpha 2 greater than alpha 1; 4.66). The isolated rat aorta was 12-200-fold more sensitive to the alpha 1-adrenoceptor agonists phenylephrine and SK & F 89748-A, than to the alpha 2-agonists, BHT-920 and M-7. Prazosin is 245-1259-fold more potent than rauwolscine as an antagonist of contractions induced by various alpha 1- and alpha 2-agonists in the rat aorta. These data indicate that constriction of the smooth muscle of the rat aorta to alpha-adrenergic agonists is mediated through alpha 1- but not alpha 2-adrenoceptors.
根据组织对选择性α1和α2肾上腺素能激动剂及拮抗剂的敏感性，对分离出的大鼠主动脉中的突触后α肾上腺素能受体进行了特性描述。非选择性α激动剂去甲肾上腺素和相对选择性激动剂的效价（-log EC50）顺序如下：去甲肾上腺素（α1 = α2；7.30）；可乐定（α2大于α1；7.01）；去氧肾上腺素（α1大于α2；6.99），SK&F 89748 - A（α1大于α2；6.65）；BHT - 920（α2远大于α1；5.56）和M -7（α2大于α1；4.66）。分离出的大鼠主动脉对α1肾上腺素能激动剂去氧肾上腺素和SK&F 89748 - A的敏感性比对α2激动剂BHT - 920和M -7高12 - 200倍。在大鼠主动脉中，作为各种α1和α2激动剂诱导的收缩的拮抗剂，哌唑嗪的效力比萝芙素高245 - 1259倍。这些数据表明，大鼠主动脉平滑肌对α肾上腺素能激动剂的收缩是通过α1而非α2肾上腺素能受体介导的。
