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 æl 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 percent Evans blue infusion. Centrally administered insulin (42.0 ng/æl) increased the urinary output of sodium (from 855.6 ± 85.1 to 2055 ± 310.6 delta percent/min; N = 11) and potassium (from 460.4 ± 100 to 669 ± 60.8 delta percent/min; N = 11). The urinary sodium excretion response to icv insulin microinjection was markedly attenuated by previous central STZ (100 æg/3 æl) administration (from 628 ± 45.8 to 617 ± 87.6 delta percent/min; N = 5) or by icv injection of a dopamine antagonist, haloperidol (4 æg/3 æl) (from 498 ± 39.4 to 517 ± 73.2 delta percent/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
Assuntos
Animais , Masculino , Ratos , Encéfalo , Taxa de Filtração Glomerular , Insulina , Natriurese , Receptor de Insulina , Transdução de Sinais , Antibióticos Antineoplásicos , Injeções Intraventriculares , Injeções Subcutâneas , Ratos Wistar , Estreptozocina , Fatores de TempoRESUMO
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 microl 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/ micro l) 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 micro g/3 micro l) administration (from 628 45.8 to 617 87.6 delta%/min; N = 5) or by icv injection of a dopamine antagonist, haloperidol (4 micro g/3 micro l) (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.
Assuntos
Encéfalo/efeitos dos fármacos , Taxa de Filtração Glomerular/efeitos dos fármacos , Insulina/administração & dosagem , Natriurese/efeitos dos fármacos , Receptor de Insulina/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos , Injeções Intraventriculares , Injeções Subcutâneas , Masculino , Ratos , Ratos Wistar , Estreptozocina , Fatores de TempoRESUMO
A study was performed to develop a fermented milk beverage with the aim to increase the potential application of buffalo cheese whey and soymilk. A mixed substrate was prepared by selective combination, which contained buffalo cheese whey 35%, soymilk 30% and cow milk 35%. The substrate mixture was fermented by a mixed culture of Lactobacillus casei shirota and Bifidobacterium adolescentis at 37 degrees C for 8 h keeping a 1:1.5 proportion between the lactic and bifidobacteria within a 5% (v/v) inoculum size. The fermented beverage was lightly extra-flavoured with vanilla essence and subjected to chemical, microbiological and sensory evaluations during storage for 28 days at 4 degrees C. Except a slight variation in the acidity, no other properties changed even after 28 days. There were no contaminating organisms (Salmonella and coliforms), which indicated the sanitary and hygienic conditions of the processing and the viable cells of the bacterial strains was well within recommended limits (6.8 x 10(8) cells for L. casei and 2.3 x 10(7) cells for Bifidobacterium). No negative changes were found in the sensory characteristics of the beverage allowing its good acceptability in all during the storage period.