title: Age-related changes in the renal dopaminergic system and expression of renal amino acid transporters in WKY and SHR rats.
abstract: This study examined age-related changes in renal dopaminergic activity and expression of amino acid transporters potentially involved in renal tubular uptake of l-DOPA in Wistar Kyoto (WKY) and spontaneously hypertensive rats. Aging (from 13 to 91 weeks) was accompanied by increases in systolic blood pressure (SBP) in both WKY and SHR. The sum of urinary dopamine and DOPAC and the urinary dopamine/l-DOPA ratio were increased in aged SHR but not in aged WKY. The urinary dopamine/renal delivery of l-DOPA ratio was increased in both rat strains with aging. LAT2 abundance was increased in aged WKY and SHR. The expression of 4F2hc was markedly elevated in aged SHR but not in aged WKY. ASCT2 was upregulated in both aged WKY and SHR. Plasma aldosterone levels and urinary noradrenaline levels were increased in aged WKY and SHR though levels of both entities were more elevated in aged SHR. Activation of the renal dopaminergic system is more pronounced in aged SHR than in aged WKY and is associated with an upregulation of renal cortical ASCT2 in WKY and of LAT2/4F2hc and ASCT2 in SHR. This activation may be the consequence of a counter-regulatory mechanism for stimuli leading to sodium reabsorption.
authors.affiliation: Institute of Pharmacology & Therapeutics, Faulty of Medicine, University of Porto, 4200-319 Porto, Portugal.
authors.forename: Vanda
authors.initials: V
authors.lastname: Pinto
authors.forename: João
authors.initials: J
authors.lastname: Amaral
authors.forename: Elisabete
authors.initials: E
authors.lastname: Silva
authors.forename: Sónia
authors.initials: S
authors.lastname: Simão
authors.forename: José Miguel
authors.initials: JM
authors.lastname: Cabral
authors.forename: Joana
authors.initials: J
authors.lastname: Afonso
authors.forename: Maria Paula
authors.initials: MP
authors.lastname: Serrão
authors.forename: Pedro
authors.initials: P
authors.lastname: Gomes
authors.forename: Maria João
authors.initials: MJ
authors.lastname: Pinho
authors.forename: Patrício
authors.initials: P
authors.lastname: Soares-da-Silva
mesh_terms: D015102:3,4-Dihydroxyphenylacetic Acid / Q000652:urine; D000375:Aging / Q000378:metabolism*; D026962:Amino Acid Transport System ASC / Q000096:biosynthesis*; D027182:Amino Acid Transport System y+ / Q000096:biosynthesis*; D000818:Animals; D004298:Dopamine / Q000652:urine*; D027301:Fusion Regulatory Protein 1, Light Chains / Q000096:biosynthesis*; D007672:Kidney Cortex / Q000378:metabolism*; D008297:Male; D015778:Minor Histocompatibility Antigens; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D026962:Amino Acid Transport System ASC; D027182:Amino Acid Transport System y+; D027301:Fusion Regulatory Protein 1, Light Chains; D015778:Minor Histocompatibility Antigens; C498849:Slc1a5 protein, rat; C486582:Slc7a8 protein, rat; D015102:3,4-Dihydroxyphenylacetic Acid; D004298:Dopamine