12月与10周龄大鼠主动脉功能性α1肾上腺素受体亚型比较

COMPARISON OF FUNCTIONALα1-ADRENOCEPTOR SUBTYPES IN AORTAE BETWEEN 12 MONTHAND 10 WEEK-OLD RATS

本文采用离体血管收缩功能实验方法，比较12月与10周龄大鼠主动脉α1肾上腺素受体（α1－AR）及其亚型的分布。结果显示：12月龄大鼠与10周龄大鼠相比，去甲肾上腺素（NE）引起的最大收缩反应显著降低，而半效激动浓度（pD2）值无显著性改变；氯乙基可乐定（CEC，不可逆阻断。α1B－AR和α1D－AR亚型）对NE引起血管收缩的抑制作用明显减弱；WB4101（α1A－AR和α1D－AR选择性拮抗剂）抬抗NE缩血管效应的pA2值没有改变；BMY7378（α1D－AR选择性拮抗剂）的半效抑制浓度（pA2）值明显降低；Sertindole（α1A－AR选择性拮抗剂）的pA2值显著增大。上述结果提示，12月龄大鼠介导主动脉收缩效应的α1－AR由10周龄以。α1D－AR亚型为主转变为α1A－AR和α1D－AR亚型共同参与，且以α1A－AR亚型为主。

The distribution of al-adrenoceptor and its subtypes in isolated aortue was compared between 12 month- and 10 week-old Wistar rats by determinating vasoconstrictorresponses. In the 12 month-old rats, compared with the 10 week-old rats, (1) themaximal contraction induced by norepinephrine (NE) was reduced, without significantalteration of pD2 value; (2) the inhibitory effect of chlorethylclonidine (an irreversibleantagonist forα1B andα1D subtype) on NE-induced contraction was weaker 3 (3) usingNE as an agonist, the pA2 value for WB4101 (an α1A- and α1D-selective antagonist)was not changed, but the pA2 value for BMY7378 (an α1D-selective antagonist) was decreased, while the pA2 value for sertindole (an α1A-selective antagonist) was increased.Thus, differently from the 10 week-old rats in which only α1D-adrenoceptors mediateNE-induced contraction in aortae, both α1A- and α1D- adrenoceptors (mainly α1A) mediate the response in the 12 month-old rats.