Age-related changes in the renal dopaminergic system and expression of renal amino acid transporters in WKY and SHR rats

• Published in: Mechanisms of ageing and development Vol. 132; no. 6; pp. 298 - 304
• Main Authors: Pinto, Vanda, Amaral, João, Silva, Elisabete, Simão, Sónia, Cabral, José Miguel, Afonso, Joana, Serrão, Maria Paula, Gomes, Pedro, Pinho, Maria João, Soares-da-Silva, Patrício
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.06.2011; Elsevier
• Subjects: 3,4-Dihydroxyphenylacetic Acid - urine; Aging; Aging - metabolism; Amino Acid Transport System ASC - biosynthesis; Amino Acid Transport System y+ - biosynthesis; Amino acid transporters; Animals; Biological and medical sciences; Development. Metamorphosis. Moult. Ageing; Dopamine - urine; Fundamental and applied biological sciences. Psychology; Fusion Regulatory Protein 1, Light Chains - biosynthesis; Hypertension; Kidney Cortex - metabolism; Male; Minor Histocompatibility Antigens; Neurohumoral activity; Rats; Rats, Inbred SHR; Rats, Inbred WKY; Renal dopaminergic system; Vertebrates: anatomy and physiology, studies on body, several organs or systems; lAT1; Hypertension; lAT2; DOPAC; WKY; 4F2hc; COMT; Neurohumoral activity; SDS-PAGE; GFR; Ccr; Amino acid transporters; ANOVA; FE Na+; l-DOPA; Aging; Renal dopaminergic system; SEM; SHR; GAPDH; Senescence; Dopamine; Rat; Ageing; Rodentia; Cardiovascular disease; Catecholamine; Vertebrata; Mammalia; Aminoacid; Neurotransmitter; Age; Carrier protein
• ISSN: 0047-6374; 1872-6216
• DOI: 10.1016/j.mad.2011.06.003

► Systolic blood pressure (SBP) increased with age in both WKY and SHR but levels were more enhanced in aged SHR than in aged WKY. ► 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. ► Increases in neurohumoral parameters were observed in aged animals, however, neurohumoral activation was greater in aged SHR than in age-matched WKY. 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.