• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.6
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• pp.1518-1524
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• 2008

Ponciri Fructus (PF), the immature fruit of Poncirus trifoliata, has been used for treatment of constipation in Korean traditional medicine. It has been reported that PF has a prokinetic effect on gastrointestinal tract, but little is known about the effect on colonic contraction. The aim of this study was to investigate the effect of PF on spontaneous contractions of proximal and distal colon in rats. The aqueous extract of PF was centrifuged and filtered and its supernatant was used for in vitro motility study. The removed colon from rats was divided into proximal and distal segments. Each segment was mounted in a 10 ml organ bath and measured the change of the spontaneous contraction with increasing dose (1, 5, 10, 50, 100, 500, $1000{\mu}g/ml$) of PF extract administration. Also the effect of PF on the spontaneous contraction was measured under treatment of atropine, acetylcholine (Ach), and tetrodotoxin (TTX). PF increased the spontaneous phasic contraction of distal colon dose dependently, but there was no change in proximal colon. The contractile response induced by PF in distal colon was lower than that of Ach and was partially blocked by atropine ($10^{-6}M$). TTX increased the spontaneous contraction and it was reinforced with Ach addition. But the extract of PF had no or little contractile effect of TTX in colon. PF increased spontaneous contractions selectively in distal colon. The prokinetic effect of PF may be due to enhancement of cholinergic related excitatory neural system.