title: Field trial of GABA-fortified rice plants and oral administration of milled rice in spontaneously hypertensive rats.
abstract: Hypertension is one of the most critical risk factors accompanying cardiovascular diseases. γ-Aminobutyric acid (GABA) is a non-protein amino acid that functions as a major neurotransmitter in mammals and also as a blood-pressure lowering agent. We previously produced GABA-fortified rice lines of a popular Japonica rice cultivar 'Koshihikari' by genetic manipulation of GABA shunt-related genes. In the study reported here, we grew these same novel rice lines in a field trial and administered the milled rice orally to rats. The yield parameters of the transgenic rice plants were almost unchanged compared to those of untransformed cv. 'Koshihikari' plants, while the rice grains of the transgenic plants contained a high GABA content (3.5 g GABA/kg brown rice; 0.75-0.85 GABA g/kg milled rice) in a greenhouse trial. Oral administration of a diet containing 2.5% GABA-fortified rice, with a daily intake for 8 weeks, had an approximately 20 mmHg anti-hypertensive effect in spontaneous hypertensive rats but not in normotensive Wistar-Kyoto rats. These results suggest that GABA-fortified rice may be applicable as a staple food to control or prevent hypertension.
authors.affiliation: Department of Biological Science, Shimane University, Nishikawatsu 1060, Matsue, Shimane, 690-8504, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Kowaka
authors.forename: Yasuka
authors.initials: Y
authors.lastname: Shimajiri
authors.forename: Kouhei
authors.initials: K
authors.lastname: Kawakami
authors.forename: Miki
authors.initials: M
authors.lastname: Tongu
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Akama
mesh_terms: D000284:Administration, Oral; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D005527:Food, Fortified; D006973:Hypertension / Q000178:diet therapy*; D008297:Male; D012275:Oryza / Q000737:chemistry / Q000235:genetics*; D030821:Plants, Genetically Modified; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D000596:Amino Acids; D005680:gamma-Aminobutyric Acid