Consequences of cerebroventricular insulin injection on renal sodium handling in rats: effect of inhibition of central nitric oxide synthase
Braz. j. med. biol. res
; 42(12): 1196-1202, Dec. 2009. ilus, tab
Artigo
em Inglês
| LILACS
| ID: lil-532292
Biblioteca responsável:
BR1.1
ABSTRACT
In the present study, we investigated the effects of acute intracerebroventricular (icv) insulin administration on central mechanisms regulating urinary sodium excretion in simultaneously centrally NG-nitro-L-arginine methylester (L-NAME)-injected unanesthetized rats. Male Wistar-Hannover rats were randomly assigned to one of five groups a) icv 0.15 M NaCl-injected rats (control, N = 10), b) icv dose-response (1.26, 12.6 and 126 ng/3 µL) insulin-injected rats (N = 10), c) rats icv injected with 60 µg L-NAME in combination with NaCl (N = 10) or d) with insulin (N = 10), and e) subcutaneously insulin-injected rats (N = 5). Centrally administered insulin produced an increase in urinary output of sodium (NaCl 855.6 ± 85.1 Ä percent/min; 126 ng insulin 2055 ± 310.6 Ä percent/min; P = 0.005) and potassium (NaCl 460.4 ± 100 Ä percent/min; 126 ng insulin 669.2 ± 60.8 Ä percent/min; P = 0.025). The urinary sodium excretion response to icv 126 ng insulin microinjection was significantly attenuated by combined administration of L-NAME (126 ng insulin 1935 ± 258.3 Ä percent/min; L-NAME + 126 ng insulin 582.3 ± 69.6 Ä percent/min; P = 0.01). Insulin-induced natriuresis occurred by increasing post-proximal sodium excretion, despite an unchanged glomerular filtration rate. Although the rationale for decreased urinary sodium excretion induced by combined icv L-NAME and insulin administration is unknown, it is tempting to suggest that perhaps one of the efferent signals triggered by insulin in the CNS may be nitrergic in nature.
Texto completo:
Disponível
Coleções:
Bases de dados internacionais
Base de dados:
LILACS
Assunto principal:
Encéfalo
/
Óxido Nítrico Sintase
/
Insulina
/
Natriurese
Limite:
Animais
Idioma:
Inglês
Revista:
Braz. j. med. biol. res
Assunto da revista:
Biologia
/
Medicina
Ano de publicação:
2009
Tipo de documento:
Artigo
/
Documento de projeto
País de afiliação:
Brasil
Instituição/País de afiliação:
Universidade Estadual de Campinas/BR
/
Universidade Federal de Uberlândia/BR