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Neuronal Nitric Oxide Synthase Activation Is Involved in Insulin-Mediated Cardiovascular Effects in the Nucleus Tractus Solitarii of Rats
- Source :
- Neuroscience. 159:727-734
- Publication Year :
- 2009
- Publisher :
- Elsevier BV, 2009.
-
Abstract
- Neuronal nitric oxide synthases (nNOS) is distributed throughout the central nervous system (CNS) and has been proposed to modulate neuronal activity in the nucleus tractus solitarii (NTS). Here, we investigated whether the activation of nNOS is involved in insulin-induced cardiovascular responses in the NTS. Insulin (100 IU/ml) was unilaterally microinjected into the NTS, and the cardiovascular effects were evaluated before and after microinjection of the nNOS inhibitors 7-nitroindazole (7-NI) (5 pmol) and N(5)-(1-imino-3-butenyl)- l- ornithine (vinyl-L-NIO) (600 pmol). Western blot and immunohistochemical analyses were performed to determine nNOS phosphorylation levels after insulin or phosphoinositide 3-kinase (PI3K) inhibitor LY294002 microinjection into the NTS. Unilateral microinjection of insulin into the NTS produced prominent depressor and bradycardic effects in WKY rats. Pretreatment with the nNOS inhibitors 7-NI and Vinyl-L-NIO attenuated the cardiovascular response evoked by insulin in Wistar-Kyoto (WKY) rats. Moreover, Western blot analysis showed a significant increase in nNOS (16.5±0.4-fold; P n =4) phosphorylation after insulin injection, whereas the PI3K inhibitor LY294002 abolished the insulin-induced effects. In situ nNOS phosphorylation was found to be increased in the NTS after insulin injection. Furthermore, co-immunoprecipitation assay showed Akt and nNOS can bind to each other as detected by phospho-Akt S473 and phospho-nNOS S1416 antibodies. In vitro kinase assay showed insulin activated Akt can directly phosphorylate nNOS S1416 . These results demonstrated that nNOS may couple with the activation of the insulin receptor, via the liberation of NO, in order to participate in central cardiovascular regulation of WKY rats.
- Subjects :
- Male
Ornithine
inorganic chemicals
medicine.medical_specialty
Indazoles
Microinjections
Morpholines
medicine.medical_treatment
Blood Pressure
Nitric Oxide Synthase Type I
Rats, Inbred WKY
Gene Expression Regulation, Enzymologic
chemistry.chemical_compound
Heart Rate
Internal medicine
Solitary Nucleus
medicine
Animals
Immunoprecipitation
Insulin
Drug Interactions
LY294002
Enzyme Inhibitors
Protein kinase B
Microinjection
Analysis of Variance
Dose-Response Relationship, Drug
biology
Chemistry
Kinase
General Neuroscience
Solitary nucleus
Rats
Enzyme Activation
Nitric oxide synthase
Insulin receptor
Endocrinology
nervous system
Chromones
cardiovascular system
biology.protein
Subjects
Details
- ISSN :
- 03064522
- Volume :
- 159
- Database :
- OpenAIRE
- Journal :
- Neuroscience
- Accession number :
- edsair.doi.dedup.....5f2e1f7b9c35ebc081b2c17d2dae1a2f