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Inhibiting endocannabinoid biosynthesis: a novel approach to the treatment of constipation
Author(s) -
Bashashati M,
Nasser Y,
Keenan C M,
Ho W,
Piscitelli F,
Nalli M,
Mackie K,
Storr M A,
Di Marzo V,
Sharkey K A
Publication year - 2015
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/bph.13114
Subject(s) - endocannabinoid system , diacylglycerol lipase , medicine , endocrinology , enteric nervous system , cholinergic , myenteric plexus , monoacylglycerol lipase , biology , pharmacology , biochemistry , receptor , immunohistochemistry
Background and Purpose Endocannabinoids are a family of lipid mediators involved in the regulation of gastrointestinal ( GI ) motility. The expression, localization and function of their biosynthetic enzymes in the GI tract are not well understood. Here, we examined the expression, localization and function of the enzyme diacylglycerol lipase‐α ( DAGL α), which is involved in biosynthesis of the endocannabinoid 2‐arachidonoylglycerol (2‐ AG ). Experimental Approach Cannabinoid CB 1 receptor‐deficient, wild‐type control and C 3 H / H e J mice, a genetically constipated strain, were used. The distribution of DAGL α in the enteric nervous system was examined by immunohistochemistry. Effects of the DAGL inhibitors, orlistat and OMDM ‐188 on pharmacologically induced GI hypomotility were assessed by measuring intestinal contractility in vitro and whole gut transit or faecal output in vivo . Endocannabinoid levels were measured by mass spectrometry. Key Results DAGL α was expressed throughout the GI tract. In the intestine, unlike DAGL β, DAGL α immunoreactivity was prominently expressed in the enteric nervous system. In the myenteric plexus, it was colocalized with the vesicular acetylcholine transporter in cholinergic nerves. In normal mice, inhibiting DAGL reversed both pharmacologically reduced intestinal contractility and pharmacologically prolonged whole gut transit. Moreover, inhibiting DAGL normalized faecal output in constipated C 3 H / H e J mice. In colons incubated with scopolamine, 2‐ AG was elevated while inhibiting DAGL normalized 2‐ AG levels. Conclusions and Implications DAGL α was expressed in the enteric nervous system of mice and its inhibition reversed slowed GI motility, intestinal contractility and constipation through 2‐ AG and CB 1 receptor‐mediated mechanisms. Our data suggest that DAGL α inhibitors may be promising candidates for the treatment of constipation.