title: L-Arginine L-Glutamate Enhances Gastric Motor Function in Rats and Dogs and Improves Delayed Gastric Emptying in Dogs.
abstract: Amino acids are not only constituents of proteins, but also have multiple physiologic functions. Recent findings have revealed that ingested amino acids either activate luminal receptors or are metabolized, causing physiologic reactions in the gastrointestinal (GI) tract. We examined the effect of oral L-arginine L-glutamate (ArgGlu), a pharmaceutical amino acid salt used i.v. for the treatment of hyperammonemia, on gastric motor function in rats and dogs. Gastric emptying was determined using phenol red and13C-breath test methods, whereas gastric relaxation was determined using the barostat method. ArgGlu (10-30 mg/kg, p.o.) dose-dependently promoted gastric emptying in rats. This effect was dependent on vagus nerve activation and comparable to that of the prokinetic mosapride. Intragastric ArgGlu (3-30 mg/kg intragastrically) also dose-dependently enhanced adaptive relaxation of rat stomachs, which was negated not by vagotomy of gastric branches, but by pretreatment with N omega-nitro-L-arginine methyl ester (20 mg/kg i.v.), a nitric oxide synthase inhibitor. Its relaxing effect on the stomach was also confirmed in dogs and was equally as efficacious as treatment with sumatriptan (1-3 mg/kg s.c.). ArgGlu (30 mg/kg p.o.) significantly reduced the half gastric emptying time in clonidine-induced delayed gastric emptying of solids in dogs, and its effect was comparable to that of cisapride (3 mg/kg p.o.). This study demonstrated that the pharmaceutical ingredient ArgGlu, currently used i.v., enhanced gastric motor function when administered orally, suggesting that it could be a new oral medicine indicated for treatment of upper GI hypofunction or dysfunction like functional dyspepsia.
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Ikumi
authors.initials: I
authors.lastname: Ishibashi-Shiraishi
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Shiraishi
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Shinichi
authors.initials: S
authors.lastname: Fujita
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Saori
authors.initials: S
authors.lastname: Ogawa
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kaneko
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Research Institute, EA Pharma (formerly known as Ajinomoto Pharmaceuticals), Kanagawa, Japan tatsuro_tanaka@eapharma.co.jp.
authors.forename: Tatsuro
authors.initials: T
authors.lastname: Tanaka
mesh_terms: D000284:Administration, Oral; D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology*; D003000:Clonidine / Q000494:pharmacology; D004285:Dogs; D005260:Female; D005746:Gastric Emptying / Q000187:drug effects*; D018698:Glutamic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects; D051381:Rats; D013270:Stomach / Q000187:drug effects* / Q000502:physiology*
chemical_list: D018698:Glutamic Acid; D001120:Arginine; D003000:Clonidine