title: Monosodium glutamate intake affect the function of the kidney through NMDA receptor.
abstract: OBJECTIVE
  We investigated whether the chronic intake of monosodium glutamate (MSG) with food affects kidney function, and renal response to glycine. We also established if the NMDA receptors are involved in the changes observed.
  
  
  METHODS
  Male Wistar rats (5weeks old) were fed a diet supplemented with MSG (3g/kg b.w./day), five days a week, and spontaneous ingestion of a 1% MSG solution during 16weeks. NaCl rats were fed a diet with NaCl (1g/kg b.w./day) and 0.35% NaCl solution at the same frequency and time. Control group was fed with normal chow and tap water. We utilized clearance techniques to examine glomerular filtration rate (GFR) and cortical renal plasma flow (CRPF) response to glycine and glycine+MK-801 (antagonist NMDA-R), and we determined NMDA-R1 in kidney by immunohistochemistry.
  
  
  RESULTS
  The addition of MSG in the diet of rats increased both GFR and CRPF with an increase of absolute sodium reabsorption. However, hyperfiltration was accompanied with a normal response to glycine infusion. Immunostain of kidney demonstrate that the NMDA receptor is upregulated in rats fed with MSG diet. NMDA-R antagonist MK-801 significantly reduced both the GFR and CRPF; however the percentage of reduction was significantly higher in the group MSG. MK-801 also reduces fractional excretion of water, sodium and potassium in the three groups.
  
  
  CONCLUSIONS
  Renal NMDAR may be conditioned by the addition of MSG in the diet, favoring the hyperfiltration and simultaneously Na retention in the body.
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina. Electronic address: smahieu@fbcb.unl.edu.ar.
authors.forename: Stella
authors.initials: S
authors.lastname: Mahieu
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: Maximiliano
authors.initials: M
authors.lastname: Klug
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: Néstor
authors.initials: N
authors.lastname: Millen
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: Ana
authors.initials: A
authors.lastname: Fabro
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: Adriana
authors.initials: A
authors.lastname: Benmelej
authors.affiliation: Laboratorio de Investigaciones Nutricionales, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.
authors.forename: Maria Del Carmen
authors.initials: Mdel C
authors.lastname: Contini
mesh_terms: D000818:Animals; D016291:Dizocilpine Maleate / Q000494:pharmacology; D005919:Glomerular Filtration Rate / Q000187:drug effects / Q000502:physiology; D007668:Kidney / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis* / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D012970:Sodium Glutamate / Q000008:administration & dosage*
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; D012970:Sodium Glutamate
keywords: Glycine; Monosodium glutamate; NMDA-R; Renal functions