Data/hora: 09/06/2024 09:48:59

Provedor de dados: | 56
País: | Brazil
Título: | Effect of intracerebroventricularly injected insulin on urinary sodium excretion by cerebroventricular streptozotocin-treated rats
Autores: | Macedo,R.F.; Furlan,F.C.; Marshall,P.S.; Michelotto,J.B.; Gontijo,J.A.R.
Data: | 2003-09-01
Ano: | 2003
Palavras-chave: | Central nervous system; Insulin; Natriuresis; Streptozotocin; Lithium clearance.
Resumo: | Recent evidence suggests that insulin may influence many brain functions. It is known that intracerebroventricular (icv) injection of nondiabetogenic doses of streptozotocin (STZ) can damage insulin receptor signal transduction. In the present study, we examined the functional damage to the brain insulin receptors on central mechanisms regulating glomerular filtration rate and urinary sodium excretion, over four periods of 30 min, in response to 3 µl insulin or 0.15 NaCl (vehicle) injected icv in STZ-treated freely moving Wistar-Hannover rats (250-300 g). The icv cannula site was visually confirmed by 2% Evans blue infusion. Centrally administered insulin (42.0 ng/µl) increased the urinary output of sodium (from 855.6 ± 85.1 to 2055 ± 310.6 delta%/min; N = 11) and potassium (from 460.4 ± 100 to 669 ± 60.8 delta%/min; N = 11). The urinary sodium excretion response to icv insulin microinjection was markedly attenuated by previous central STZ (100 µg/3 µl) administration (from 628 ± 45.8 to 617 ± 87.6 delta%/min; N = 5) or by icv injection of a dopamine antagonist, haloperidol (4 µg/3 µl) (from 498 ± 39.4 to 517 ± 73.2 delta%/min; N = 5). Additionally, insulin-induced natriuresis occurred by increased post-proximal tubule sodium rejection, despite an unchanged glomerular filtration rate. Excluding the possibility of a direct action of STZ on central insulin receptor-carrying neurons, the current data suggest that the insulin-sensitive response may be processed through dopaminergic D1 receptors containing neuronal pathways.
Tipo: | Info:eu-repo/semantics/other
Idioma: | Inglês
Identificador: | http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000900008
Editor: | Associação Brasileira de Divulgação Científica
Relação: | 10.1590/S0100-879X2003000900008
Formato: | text/html
Fonte: | Brazilian Journal of Medical and Biological Research  v.36 n.9 2003
Fonte: | info:eu-repo/semantics/openAccess