Effects of injection of selective adrenergic receptor antagonists into the lateral hypothalamic area on renal function.
Braz J Med Biol Res
; 23(11): 1205-8, 1990.
Article
em En
| MEDLINE
| ID: mdl-1983458
Studies were undertaken to characterize the participation of specific alpha-1,alpha-2 and beta adrenoceptors of the lateral hypothalamic area (LHA) in the urinary excretion of sodium and potassium. Alpha-1 and alpha-2 LHA receptors were shown to participate in the regulation of renal sodium and potassium excretion. The effects of noradrenaline microinjection (30 nmol in 1 microliter) into the LHA on urinary sodium excretion (UNaV) are blocked by previous injection of the alpha-1 antagonist prazosin (4 nmol in 1 microliter) from 3.22 +/- 0.25 to 0.59 +/- 0.04 microEq min-1 100 g body weight-1. Pre-injection of yohimbine, an alpha-2 antagonist (4 nmol in 1 microliter), synergistically potentiated the action of noradrenaline on UNaV (3.22 +/- 0.25 to 4.02 +/- 0.27 microEq min-1 100 g body weight-1) and on urinary potassium excretion (UKV) (0.70 +/- 0.08 to 1.15 +/- 0.12 microEq min-1 100 g body weight-1). The beta-adrenergic blockers metoprolol (100 nmol in 1 microliter) and propranolol (100 nmol in 1 microliter) had no synergistic or antagonistic action on the sodium excretion fraction, suggesting that neither of these receptors is present in LHA. Our results indicate that natriuresis occurs even in the absence of changes in glomerular filtration rate and demonstrate an inhibitory natriuretic effect of an alpha-1 blocker (prazosin) injected into the LHA before adrenaline, while an alpha-2 antagonist (yohimbine) yielded a potentiating effect.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Sódio
/
Antagonistas Adrenérgicos alfa
/
Antagonistas Adrenérgicos beta
/
Região Hipotalâmica Lateral
Limite:
Animals
Idioma:
En
Revista:
Braz J Med Biol Res
Ano de publicação:
1990
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Brasil