CB1, CB2, PPARα, TRPV1, GPR119 and GPR55 receptors were found to be expressed in the gastrointestinal tract. Endocannabinoids such as AEA, PEA, and OEA are biosynthesized in the gastrointestinal tract where they play a role in controlling several gastrointestinal processes through the binding of the endocannabinoid receptors (Borrelli & Izzo, 2009; Izzo, Muccioli, Ruggieri, & Schicho, 2015; Taschler, Hasenoehrl, Storr, & Schicho, 2016).
In rats, plant cannabinoids can also help in controlling the transit and motility of the gastrointestinal tract (Shook & Burks, 1989).
It was shown that G Protein-Coupled Receptor 12 plays a role in the modulation of metastasis process in cancer cells and CBD functions as an inverse agonist for this receptor (Brown, Laun, & Song, 2017).
It was shown that THC may help alleviate nausea and vomiting symptoms connected to gastric cancer (Gonzalez-Rosales & Walsh, 1997).
It was shown that AEA addition to the human gastric cancer cell line, HGC-27, stimulated cell proliferation at lower AEA concentrations, while cell proliferation was strongly inhibited through the induction of apoptosis at higher concentrations. A combination of high doses of AEA with the anticancer drug Paclitaxel exhibited a synergistic effect on cell growth, reducing gastric cancer cell viability (Miyato et al., 2009).
In both animal models and in vitro assays of gastric cancer, synthetic CB1 agonist WIN 55,212-2 was shown to exhibit antineoplastic and antiproliferative activity and has been suggested as an alternative to 5-Fluorouracil resistant gastric cancer cells (Oh et al., 2013; Park et al., 2011; X. Xian et al., 2016; X.-S. Xian et al., 2010; X.-S. Xian, Park, Choi, & Park, 2013).
In an in vitro study, it was demonstrated that cannabinoid receptor agonists such as anandamide (AEA), (R)-(+)-methanandamide (Meth-AEA), and CP 55,940 (CP) showed similar effects in decreasing cell viability of gastric cancer cells, highlighting the therapeutic potential of these receptor agonists in gastric cancer cells (Ortega et al., 2016).