Cohen M L, Shaar C J, Colbert W E
J Cardiovasc Pharmacol. 1984 Nov-Dec;6(6):1245-8.
LY171555 is the active enantiomer of the racemate LY141865, a selective DA2-receptor agonist. LY171555 (10(-7)-10(-4) M) inhibited the twitch response to field stimulation in the adrenergically innervated rat vas deferens, a response due to activation of alpha 2-receptors as evidenced by total blockade with yohimbine (10(-6) M). The dopamine receptor antagonist sulpiride (10(-5) M) produced a small shift in the concentration-response curve to LY171555, consistent with the modest alpha 2-antagonist activity of sulpiride. LY171555 (10(-10)-10(-8) M) inhibited prolactin release from the anterior pituitary in vitro, a response due to activation of DA2-receptors as indicated by total blockade with sulpiride (10(-6) M). Thus, in addition to its predominant DA2-agonist activity, LY171555 can activate alpha 2-receptors in concentrations similar to those necessary for activation of histamine H2-receptors. Such concentrations were approximately 2,250-fold higher than necessary for DA2-receptor activation.
LY171555是消旋体LY141865的活性对映体，一种选择性DA2受体激动剂。LY171555（10^-7 - 10^-4 M）抑制去甲肾上腺素能神经支配的大鼠输精管对场刺激的抽搐反应，育亨宾（10^-6 M）完全阻断证明该反应是由α2受体激活引起的。多巴胺受体拮抗剂舒必利（10^-5 M）使LY171555的浓度-反应曲线略有偏移，这与舒必利适度的α2拮抗剂活性一致。LY171555（10^-10 - 10^-8 M）在体外抑制垂体前叶催乳素的释放，舒必利（10^-6 M）完全阻断表明该反应是由DA2受体激活引起的。因此，除了其主要的DA2激动剂活性外，LY171555还能以与激活组胺H2受体所需浓度相似的浓度激活α2受体。这些浓度比激活DA2受体所需浓度高约2250倍。
