Butler M, Jenkinson D H
Eur J Pharmacol. 1978 Dec 1;52(3-4):303-11. doi: 10.1016/0014-2999(78)90283-2.
The effectiveness of WB 4101, a recently described alpha-adrenoceptor antagonist, in blocking an excitatory and two inhibitory responses to alpha-receptor activation was studied. One of the inhibitory responses was the reduction by the selective alpha-agonist amidephrine of carbachol contractures of isolated guinea-pig taenia caeci. WB 4101 antagonised this inhibition with a Schild plot slope of 0.99 and a pA2 of 8.9. The same pA2 value was obtained for blockade of the contractile effect of amidephrine and noradrenaline on the rat vas deferens. WB 4101 was, however, several hundred times less active in antagonising the inhibitory effect of clonidine on the twitch response of the vas deferens to field stimulation. Incidental observations were that the twitch was increased by low concentrations of amidephrine, and by relatively high concentrations of WB 4101. Because of its potency and postsynaptic selectivity, WB 4101 should be useful for adrenoceptor classification.
研究了最近描述的α-肾上腺素能受体拮抗剂WB 4101在阻断对α受体激活的一种兴奋性反应和两种抑制性反应方面的有效性。其中一种抑制性反应是选择性α激动剂酰胺福林对离体豚鼠盲肠带的卡巴胆碱挛缩的抑制作用。WB 4101拮抗这种抑制作用，其Schild图斜率为0.99，pA2为8.9。在阻断酰胺福林和去甲肾上腺素对大鼠输精管的收缩作用时也得到了相同的pA2值。然而，WB 4101在拮抗可乐定对输精管场刺激抽搐反应的抑制作用方面的活性要低数百倍。偶然观察到低浓度的酰胺福林和相对高浓度的WB 4101会增加抽搐。由于其效力和突触后选择性，WB 4101应该有助于肾上腺素能受体的分类。
