Angiotensin-(1-7) through Mas receptor up-regulates neuronal norepinephrine transporter via Akt and Erk1/2-dependent pathways.
As angiotensin (Ang) (1-7) decreases norepinephrine (NE) content in the synaptic cleft, we investigated the effect of Ang-(1-7) on NE neuronal uptake in spontaneously hypertensive rats. [(3)H]-NE neuronal uptake was measured in isolated hypothalami. NE transporter (NET) expression was evaluated in hypothalamic neuronal cultures by western-blot. Ang-(1-7) lacked an acute effect on neuronal NE uptake. Conversely, Ang-(1-7) caused an increase in NET expression after 3 h incubation (40 ± 7%), which was blocked by the Mas receptor antagonist, a PI3-kinase inhibitor or a MEK1/2 inhibitor suggesting the involvement of Mas receptor and the PI3-kinase/Akt and MEK1/2-ERK1/2 pathways in the Ang-(1-7)-stimulated NET expression. Ang-(1-7) through Mas receptors stimulated Akt and ERK1/2 activities in spontaneously hypertensive rat neurons. Cycloheximide attenuated Ang-(1-7) stimulation of NET expression suggesting that Ang-(1-7) stimulates NET synthesis. In fact, Ang-(1-7) increased NET mRNA levels. Thus, we evaluated the long-term effect of Ang-(1-7) on neuronal NE uptake after 3 h incubation. Under this condition, Ang-(1-7) increased neuronal NE uptake by 60 ± 14% which was blocked by cycloheximide and the Mas receptor antagonist. Neuronal NE uptake and NET expression were decreased after 3 h incubation with an anti-Ang-(1-7) antibody. Ang-(1-7) induces a chronic stimulatory effect on NET expression. In this way, Ang-(1-7) may regulate a pre-synaptic mechanism in maintaining appropriate synaptic NE levels during hypertensive conditions.
Departamento de Química Biológica, IQUIFIB-CONICET, Universidad de Buenos Aires, CONICET, Buenos Aires, Argentina.
María A
MA
Lopez Verrilli
Martín
M
Rodriguez Fermepín
Nadia
N
Longo Carbajosa
Silvina
S
Landa
Bruno D
BD
Cerrato
Silvia
S
García
Belisario E
BE
Fernandez
Mariela M
MM
Gironacci
D000803:Angiotensin I / Q000494:pharmacology*; D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D019950:Mitogen-Activated Protein Kinase 1 / Q000502:physiology*; D048052:Mitogen-Activated Protein Kinase 3 / Q000502:physiology*; D009474:Neurons / Q000378:metabolism*; D050484:Norepinephrine Plasma Membrane Transport Proteins / Q000096:biosynthesis*; D051058:Oncogene Protein v-akt / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology*; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000187:drug effects*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D043562:Receptors, G-Protein-Coupled / Q000187:drug effects*; D015398:Signal Transduction / Q000187:drug effects*; D015854:Up-Regulation / Q000187:drug effects
D050484:Norepinephrine Plasma Membrane Transport Proteins; D010446:Peptide Fragments; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D000803:Angiotensin I; D051058:Oncogene Protein v-akt; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; C118790:angiotensin I (1-7)