Published online Feb 14, 2018. doi: 10.3748/wjg.v24.i6.693
Peer-review started: September 14, 2017
First decision: October 24, 2017
Revised: November 6, 2017
Accepted: November 28, 2017
Article in press: November 28, 2017
Published online: February 14, 2018
To elucidate the mechanism of patchouli alcohol (PA) in treatment of rat models of diarrhea-predominant irritable bowel syndrome (IBS-D).
We studied the effects of PA on colonic spontaneous motility using its cumulative log concentration (3 × 10−7 mol/L to 1 × 10−4 mol/L). We then determined the responses of the proximal and distal colon segments of rats to the following stimuli: (1) carbachol (1 × 10−9 mol/L to 1 × 10−5 mol/L); (2) neurotransmitter antagonists including Nω-nitro-
PA exerted a concentration-dependent inhibitory effect on the spontaneous contraction of the colonic longitudinal smooth muscle, and the half maximal effective concentration (EC50) was 41.9 μmol/L. In comparison with the KCl-treated IBS-D group, the contractile response (mg contractions) in the PA + KCl-treated IBS-D group (11.87 ± 3.34) was significantly decreased in the peak tension (P < 0.01). Compared with CCh-treated IBS-D rat colon, the cholinergic contractile response of IBS-D rat colonic smooth muscle (EC50 = 0.94 μmol/L) was significantly decreased by PA (EC50 = 37.43 μmol/L) (P < 0.05). Lack of nitrergic neurotransmitter release in stress-induced IBS-D rats showed contraction effects on colonic smooth muscle. Pretreatment with PA resulted in inhibitory effect on
PA application may serve as a new therapeutic approach for IBS-D.
Core tip: We reported the results from an isolated colonic smooth muscle experiment in a chronic wrap-restraint stress-induced rat model of diarrhea-predominant irritable bowel syndrome (IBS-D). The model enabled us to study the possible mechanisms underlying IBS-D and the inhibitory effects of patchouli alcohol (PA) on an isolated IBS-D rat colon. This study demonstrated for the first time that the PA was involved in cholinergic and nonadrenergic, noncholinergic neurotransmitter regulation in the enteric nervous system (ENS) in vitro. PA acts as a neurotransmitter agent in ENS. The results suggest that PA is a new treatment option for IBS-D.