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Titolo:
Aging, high salt intake, and renal dopaminergic activity in Fischer 344 rats
Autore:
Vieira-Coelho, MA; Hussain, T; Kansra, V; Serrao, MP; Guimaraes, JT; Pestana, M; Soares-da-Silva, P; Lokhandwala, MF;
Indirizzi:
Univ Houston, Coll Pharm, Inst Cardiovasc Studies, Houston, TX 77204 USA Univ Houston Houston TX USA 77204 rdiovasc Studies, Houston, TX 77204 USA Univ Porto, Inst Pharmacol & Therapeut, Fac Med, P-4100 Porto, Portugal Univ Porto Porto Portugal P-4100 rapeut, Fac Med, P-4100 Porto, Portugal
Titolo Testata:
HYPERTENSION
fascicolo: 4, volume: 34, anno: 1999,
parte:, 1
pagine: 666 - 672
SICI:
0194-911X(199910)34:4<666:AHSIAR>2.0.ZU;2-1
Fonte:
ISI
Lingua:
ENG
Soggetto:
SPONTANEOUSLY HYPERTENSIVE RATS; ADENYLATE-CYCLASE; URINARY-EXCRETION; PROXIMAL TUBULES; ATPASE ACTIVITY; SYSTEM ACTIVITY; DA(1) RECEPTOR; C ACTIVITY; KIDNEY; FAILS;
Keywords:
aging; kidney; dopamine; sodium; Na+, K+-ATPase;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Clinical Medicine
Life Sciences
Citazioni:
32
Recensione:
Indirizzi per estratti:
Indirizzo: Lokhandwala, MF Univ Houston, Coll Pharm, Inst Cardiovasc Studies, Houston, TX 77204 USA Univ Houston Houston TX USA 77204 , Houston, TX 77204 USA
Citazione:
M.A. Vieira-Coelho et al., "Aging, high salt intake, and renal dopaminergic activity in Fischer 344 rats", HYPERTENSIO, 34(4), 1999, pp. 666-672

Abstract

The present study examined renal dopaminergic activity and its response tohigh salt (HS) intake in adult (6-month-old) and old (24-month-old) Fischer 344 rats, Daily urinary excretion of L-3,4-dihydroxyphenylalanine (L-DOPA), dopamine, and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) andhomovanillic acid was similar in adult and old rats; by contrast, daily urinary excretion of norepinephrine in old rats was almost twice that in adult animals. HS intake (1% NaCl) over a period of 24 hours resulted in a 2-fold increase in the urinary excretion of dopamine, DOPAC, and norepinephrinein adult animals but not in old animals, Norepinephrine and L-DOPA plasma levels did not change during HS intake and were similar in both groups of rats. The natriuretic response to an HS intake in old rats (from 4.7+/-0.4 to 10.7+/-2.0 nmol . kg(-1) . d(-1); Delta=6.0+/-0.9 nmol . kg(-1) . d(-1)) was less than in adult rats (from 5.2+/-0.4 to 13.5+/-2.5 nmol . kg(-1) . d(-1); Delta=8.3+/-0.8 nmol . kg(-1) . d(-1)). A diuretic response to HS intake was observed in adult rats (from 20.9+/-2.3 to 37.6+/-2.8 mL . kg(-1) .d(-1)) but not in old rats (from 37.7+/-5.7 to 42.3+/-6.0 mL . kg(-1) . d(-1)). Dopamine levels and dopamine/L-DOPA ratios in the renal cortex of oldrats were greater than in adult rats. HS intake increased both dopamine levels and dopamine/L-DOPA ratios in the renal cortex of adult rats but not in old rats. Aromatic L-amino acid decarboxylase activity was higher in old rats than in adult rats; HS intake increased L-amino acid decarboxylase activity (nmol . mg protein(-1) 15 min(-1)) in adult rats (from 67+/-1 to 93+/-1) but not in old rats (from 86+/-2 to 87+/-2), Dopamine inhibited Na+,K+-ATPase activity in proximal tubules obtained from adult rats, but it failedto exert such an inhibitory effect in old rats. It is concluded that renaldopaminergic tonus in old rats is higher than in adult rats but fails to respond to HS intake as observed in adult rats. This may be due in part to the inability of dopamine to inhibit Na+,K+-ATPase activity in old rats.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 11/07/20 alle ore 10:55:19