Renal dopaminergic system activity in rats with different sodium content in the diet

  • Verónica De Luca Sarobe Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas Alfredo Lanari, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires (CONICET-UBA), Buenos Aires
  • Luis Di Ciano Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas Alfredo Lanari, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires (CONICET-UBA), Buenos Aires
  • Andrea M. Carranza Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas Alfredo Lanari, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires (CONICET-UBA), Buenos Aires
  • Gloria Levin Laboratorio de Catecolaminas, Hospital de Niños Ricardo Gutiérrez, Centro de Investigaciones Endocrinológicas Dr. César Bergadá, Consejo Nacional de Investigaciones Científicas y Técnicas, (CONICET), Buenos Aires
  • Elvira Arrizurieta Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas Alfredo Lanari, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires (CONICET-UBA), Buenos Aires
  • Fernando R. Ibarra Laboratorio de Riñón Experimental, Instituto de Investigaciones Médicas Alfredo Lanari, Consejo Nacional de Investigaciones Científicas y Técnicas, Universidad de Buenos Aires (CONICET-UBA), Buenos Aires
Keywords: renal dopamine, sodium, natriuresis, monoamine oxidase enzymes, catechol-O-methyltransferase, D1 receptors, Wistar rats, Na excretion

Abstract

Introduction: Renal dopamine (DA) regulates water and sodium excretion and, doing so, controls blood pressure. Renal epithelial cells produce DA by decarboxylation of filtered l-dopa and inactivate DA by monoamineoxidase (MAO) and catechol-O-methyl transferase (COMT). Dopamine interacts with specific receptors (D1R and D2R). Objective: The aim of this work is to study urinary DA excretion (UDA*V) and MAO and COMT activities in rats under different sodium intake. Four groups according to Na+ intake and treatment were studied: Normal (NS, NaCl 0.24%), Low (BS, 0.02%) and High sodium (HS, 1%) for 5 days. In group four, NS, BS and HS rats received SCH 23390 (1 mg/kg SC), D1R antagonist, the last three days. Results: UDA*V (ng/d/100g bwt) was lower in BS 571±30 vs NS 730±45, p< 0.01 and was increased in HS to 1443±203 p<0.01vs NS and p<0.001 vs BS. In BS rats MAO activity (nmol/mg/h) increased in renal cortex to 9.44±0.55 vs NS 7.66±0.52, p<0.05, while MAO decreased in HS cortex to 6.3±0.25, p<0.05 vs NS; COMT activity (pmol/mg/h), increased in cortex of BS rats to 15.67±1.23 vs 11.04±0.13 in NS group, p<0.05. Regardless Na+ intake, MAO was always higher in cortex than in renal medulla, while COMT did not show differences between cortex and medulla. SCH 23390 markedly decreased diuresis and natriuresis in HS rats and Na+ excretion in NS and increased systolic pressure in BS. Conclusion: Dopamine and Na+ excretion are positively related to Na+ intake. MAO and COMT are involved in this response mainly mediated by D1R stimulation.

Published
2010-12-01
How to Cite
1.
De Luca Sarobe V, Di Ciano L, Carranza AM, Levin G, Arrizurieta E, Ibarra FR. Renal dopaminergic system activity in rats with different sodium content in the diet. Rev Nefrol Dial Traspl. [Internet]. 2010Dec.1 [cited 2024Dec.23];30(4):153-60. Available from: http://revistarenal.org.ar/index.php/rndt/article/view/268
Section
Original Article