Kwok Y H, Mitchelson F
Can J Physiol Pharmacol. 1982 Feb;60(2):193-200. doi: 10.1139/y82-030.
The antimuscarinic activity of amitriptyline, mianserin, and viloxazine was compared with atropine in guinea-pig ileal longitudinal muscle. The pA2 values obtained using carbachol (CCh) as agonist were as follows: atropine, 9.55; amitriptyline, 7.50; mianserin, 6.40; and viloxazine, 4.91. Responses to transmural electrical stimulation (1-50 Hz) were more resistant than those produced by CCh to inhibition by atropine and the antidepressants. This did not appear to be due to a selective inhibition of prejunctional inhibitory muscarinic receptors, as a pA2 of 8.73 was obtained with atropine for the depression of oxotremorine-induced inhibition of acetylcholine (ACh) output. Amitriptyline (10 micrometers) caused a 2.4-fold increase in ACh output and was 200-fold weaker than atropine at doubling ACh output in the longitudinal muscle stimulated at 0.3 Hz. Mianserin (10 micrometers) and viloxazine (1-10 micrometers) did not significantly affect ACh output. It is suggested that the antidepressants exhibits a greater affinity for the postjunctional muscarinic receptors in the guinea-pig ileal longitudinal muscle.
在豚鼠回肠纵肌中，将阿米替林、米安色林和维洛沙嗪的抗毒蕈碱活性与阿托品进行了比较。以卡巴胆碱（CCh）作为激动剂获得的pA2值如下：阿托品为9.55；阿米替林为7.50；米安色林为6.40；维洛沙嗪为4.91。对跨壁电刺激（1 - 50Hz）的反应比CCh所产生的反应对阿托品和抗抑郁药的抑制作用更具抗性。这似乎不是由于对节前抑制性毒蕈碱受体的选择性抑制，因为阿托品对奥索震颤素诱导的乙酰胆碱（ACh）释放抑制作用的pA2值为8.73。阿米替林（10微摩尔）使ACh释放增加2.4倍，在0.3Hz刺激的纵肌中使ACh释放加倍时，其效力比阿托品弱200倍。米安色林（10微摩尔）和维洛沙嗪（1 - 10微摩尔）对ACh释放没有显著影响。提示这些抗抑郁药对豚鼠回肠纵肌中的节后毒蕈碱受体具有更高的亲和力。
