Abstract
The effects of choline and choline esters(acetylcholine, methacholine, carbachol, bethanechol) on motility of isolated rabbit jejunum segment were examined and $pD_2$ values of each drugs were compared. The results were as follows. In choline, there were revealed that maximum effective concentration was $10^{-2}M$, $ED_{50}$ was $2.4{\times}10^{-3}M$, and $pD_2$ value was 2.619. In acetylcholine, there were revealed that maximum effective concentration was $10^{-4}M$, effect was hardly showin in $10^{-9}M$ concentration, $ED_{50}$ was $0.5{\times}10^{-5}M$, and $pD_2$ value was 5.154. In methacholine, there were revealed that maximum effective concentration was $10^{-5}M$, effect was hardly shown in $10^{-9}M$ concentration, $ED_{50}$ was $9{\times}10^{-7}M$, and $pD_2$ value was 6.045. In carbachol, there were revealed that maximum effective concentration was $10^{-5}M$, effect was hardly shown in $10^{-11}M$ concentration, $ED_{50}$ was $5.7{\times}10^{-7}M$, and $pD_2$ value was 6.244. In bethanechol, there were revealed that maximum effective concentration was $10^{-4}M$, effect was hardly shown in $10^{-8}M$ concentration, $ED_{50}$ was $3.3{\times}10^{-6}M$, and $pD_2$ value was 5.480. Choline and choline esters caused contraction on motility of isolated rabbit jejunum segment. The order of $pD_2$ values of drugs was carbachol, methacholine, bethanechol, acetylcholine and choline (in the descending order of potency).
Choline과 choline esters인 acetylcholine, methacholine, carbachol, bethanechol이 토끼의 적출장관 운동에 미치는 영향과 각 약물의 $pD_2$값을 산출하여 각각 비교를 하였다. Choline은 최대유효농도가 $10^{-2}M$이었으며 $ED_{50}$은 $2.4{\times}10^{-3}M$이었고 $pD_2$값은 2.619이었다. Acetylcholine은 최대유효농도가 $10^{-4}M$이었으며 $10^{-9}M$에서는 거의 효과가 나타나지 않았고 $ED_{50}$은 $0.5{\times}10^{-5}M$이었고 $pD_2$값은 5.154이었다. Methacholine은 최대유효농도가 $10^{-5}M$이었으며 $10^{-9}M$에서는 거의 효과가 나타나지 않았고 $ED_{50}$은 $9{\times}10^{-5}M$이었고 $pD_2$값은 6.045이었다. Carbachol은 최대유효농도가 $10^{-5}M$이었으며 $10^{-11}M$에서는 거의 효과가 나타나지 않았고 $ED_{50}$은 $5.7{\times}10^{-7}M$이었고 $pD_2$값은 6.244이었다. Bethanechol은 최대유효농도가 $10^{-4}M$이었으며 $10^{-8}M$에서는 거의 효과가 나타나지 않았고 $ED_{50}$은 $3.3{\times}10^{-6}M$이었고 $pD_2$값은 5.480이었다. Choline esters는 토끼의 적출장관 운동에 대하여 수축을 일으켰으며 각 약물의 potency의 순서는 carbachol이 가장 강하게 나타났고 methacholine, bethanechol, acetylcholine, choline의 순으로 나타났다.
(College of Veterinary Medicine, Kyungpook National University)