title: Synchronization by food access modifies the daily variations in expression and activity of liver GABA transaminase.
abstract: Daytime restricted feeding (DRF) is an experimental protocol that influences the circadian timing system and underlies the expression of a biological clock known as the food entrained oscillator (FEO). Liver is the organ that reacts most rapidly to food restriction by adjusting the functional relationship between the molecular circadian clock and the metabolic networks. γ-Aminobutyric acid (GABA) is a signaling molecule in the liver, and able to modulate the cell cycle and apoptosis. This study was aimed at characterizing the expression and activity of the mostly mitochondrial enzyme GABA transaminase (GABA-T) during DRF/FEO expression. We found that DRF promotes a sustained increase of GABA-T in the liver homogenate and mitochondrial fraction throughout the entire day-night cycle. The higher amount of GABA-T promoted by DRF was not associated to changes in GABA-T mRNA or GABA-T activity. The GABA-T activity in the mitochondrial fraction even tended to decrease during the light period. We concluded that DRF influences the daily variations of GABA-T mRNA levels, stability, and catalytic activity of GABA-T. These data suggest that the liver GABAergic system responds to a metabolic challenge such as DRF and the concomitant appearance of the FEO.
authors.affiliation: Instituto de Neurobiología, Campus UNAM-Juriquilla, 76230 Querétaro, QRO, Mexico.
authors.forename: Dalia
authors.initials: D
authors.lastname: De Ita-Pérez
authors.affiliation: Instituto de Neurobiología, Campus UNAM-Juriquilla, 76230 Querétaro, QRO, Mexico.
authors.forename: Isabel
authors.identifier: 0000-0002-6731-9468
authors.initials: I
authors.lastname: Méndez
authors.affiliation: Instituto de Neurobiología, Campus UNAM-Juriquilla, 76230 Querétaro, QRO, Mexico.
authors.forename: Olivia
authors.initials: O
authors.lastname: Vázquez-Martínez
authors.affiliation: Instituto de Neurobiología, Campus UNAM-Juriquilla, 76230 Querétaro, QRO, Mexico.
authors.forename: Mónica
authors.initials: M
authors.lastname: Villalobos-Leal
authors.affiliation: Instituto de Neurobiología, Campus UNAM-Juriquilla, 76230 Querétaro, QRO, Mexico.
authors.forename: Mauricio
authors.identifier: 0000-0002-9019-8246
authors.initials: M
authors.lastname: Díaz-Muñoz
mesh_terms: D000612:4-Aminobutyrate Transaminase / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D031204:Caloric Restriction; D002940:Circadian Rhythm; D015971:Gene Expression Regulation, Enzymologic; D008099:Liver / Q000201:enzymology*; D008297:Male; D008928:Mitochondria / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017208:Rats, Wistar; D013347:Subcellular Fractions / Q000378:metabolism; D005680:gamma-Aminobutyric Acid
chemical_list: D012333:RNA, Messenger; D005680:gamma-Aminobutyric Acid; D000612:4-Aminobutyrate Transaminase