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Titolo:
Role of intrarenal alpha(2)-adrenoceptors in the renal responses to xylazine in rats
Autore:
Menegaz, RG; Kapusta, DR; Cabral, AM;
Indirizzi:
Univ Fed Espirito Santo, Dept Ciencias Fisiol, BR-29040090 Vitoria, Espirito Santo, Brazil Univ Fed Espirito Santo Vitoria Espirito Santo Brazil BR-29040090 BCrazil Louisiana State Univ, Hlth Sci Ctr, Dept Pharmacol & Expt Therapeut, New Orleans, LA 70112 USA Louisiana State Univ New Orleans LA USA 70112 , New Orleans, LA 70112 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
fascicolo: 4, volume: 278, anno: 2000,
pagine: R1074 - R1081
SICI:
0363-6119(200004)278:4<R1074:ROIAIT>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
ANESTHETIZED RATS; ALPHA-2-ADRENOCEPTOR ANTAGONISM; EXCRETORY RESPONSES; CAMP ACCUMULATION; COLLECTING TUBULE; VASOPRESSIN; AGONISTS; NERVES; CLONIDINE; STIMULATION;
Keywords:
ketamine; yohimbine; urine flow rate; urinary sodium excretion; renal sympathetic nerves; renal excretory function; kidney;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
40
Recensione:
Indirizzi per estratti:
Indirizzo: Cabral, AM Univ Fed Espirito Santo, Dept Ciencias Fisiol, BR-29040090 Vitoria, Espirito Santo, Brazil Univ Fed Espirito Santo Vitoria Espirito SantoBrazil BR-29040090 BC
Citazione:
R.G. Menegaz et al., "Role of intrarenal alpha(2)-adrenoceptors in the renal responses to xylazine in rats", AM J P-REG, 278(4), 2000, pp. R1074-R1081

Abstract

This study examined the contribution of intrarenal alpha(2)-adrenoceptor mechanisms to the enhanced urine flow rate (V) and urinary sodium excretion (UNaV) responses in ketamine-xylazine-anesthetized rats. Ten minutes after left renal artery (LRA) injection, the alpha(2)-adrenoceptor antagonist yohimbine (5 mu g) significantly decreased V from 58 +/- 8 to 35 +/- 7 mu l.min(-1).g kidney wt(-1) and UNaV from 2.8 +/- 0.4 to 2.1 +/- 0.4 mu eq.min(-1).g kidney wt(-1) without altering right kidney function. The renal effectsof the LRA injection of yohimbine were completely abolished in chronic bilaterally renal-denervated (RDNX) rats. In RDNX rats, a higher LRA dose of yohimbine (15 mu g) significantly reduced left and right kidney V, with no effects on UNaV. In separate bladder-catheterized rats, yohimbine (0.5 mg/kg), 20 min after intravenous injection, significantly decreased V from 63 +/- 9 to 13 +/- 2 mu l.min(-1).g kidney wt(-1) and UNaV from 4.5 +/- 0.5 to 1.1 +/- 0.1 mu eq.min(-1).g kidney wt(-1). In RDNX rats, this dose of yohimbine reduced V and UNaV, but the magnitude was blunted compared with intact rats. In contrast, 0.1 mg/kg iv yohimbine significantly reduced V and UN,V to similar magnitudes in intact and RDNX groups. Together, these findings indicate that intravenous xylazine acts by renal nerve-dependent and -independent mechanisms to enhance renal excretory function in ketamine-anesthetized rats. Because the effects of the LRA dose of yohimbine were abolished inrenal-denervated animals, it appears that xylazine has a direct renal action to augment the renal excretion of water and sodium via a presynaptic alpha(2)-adrenoceptor pathway that inhibits the release of neurotransmitters from renal sympathetic nerve terminals.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/01/20 alle ore 07:37:57