Tonin expression in the rat brain and tonin-mediated central production of angiotensin II

dc.contributor.authorAraujo, R. C.
dc.contributor.authorLima, M. P.
dc.contributor.authorLomez, ESL
dc.contributor.authorBader, M.
dc.contributor.authorPesquero, J. B.
dc.contributor.authorSumitani, M.
dc.contributor.authorPesquero, J. L.
dc.contributor.institutionUniversidade Federal de Minas Gerais (UFMG)
dc.contributor.institutionUniv Mogi Cruzes
dc.contributor.institutionMDC Mol Med
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.description.abstractTonins are serine proteinases mainly found in the rat submandibular gland, which are capable of generating the pressor octapeptide angiotensin II (Ang II) not only from the classical substrate angiotensin I but also from the synthetic tetradecapeptide (AG(1 - 14)) and from angiotensinogen. in this work, tonin expression levels were evaluated in astrocytes and brain areas of the rat. By two different techniques (ribonuclease protection assay and reverse transcription - polymerase chain reaction), we could verify the presence of tonin mRNA in astrocytes and in the thalamus of the rat brain. Sequencing of the amplified brain cDNA determined it to be identical to that found in the submandibular gland. Central microinjection of tonin produced a transient (10-20 min) elevation of blood pressure and heart rate and induced water and saline intake within the first 10 min after injection. Urinary volume and salt excretion increased within 7 h after tonin injection. These effects were partially blocked by previously administered losartan, indicating that tonin effectively induced a central Ang II formation. Our data suggest that tonin may be an alternative pathway to Ang II generation in the brain and could participate in the physiological effects exerted by Ang II such as water and saline intake and blood pressure elevation. (C) 2002 Elsevier Science Inc. All rights reserved.en
dc.description.affiliationUniv Fed Minas Gerais, Inst Biol Sci, Dept Physiol & Biophys, Belo Horizonte, MG, Brazil
dc.description.affiliationUniv Fed Minas Gerais, Sch Nursing, Belo Horizonte, MG, Brazil
dc.description.affiliationUniv Mogi Cruzes, São Paulo, Brazil
dc.description.affiliationMDC Mol Med, Berlin, Germany
dc.description.affiliationUniversidade Federal de São Paulo, Dept Biophys, São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Dept Biophys, São Paulo, Brazil
dc.description.sourceWeb of Science
dc.identifier.citationPhysiology & Behavior. Oxford: Pergamon-Elsevier B.V., v. 76, n. 2, p. 327-333, 2002.
dc.publisherElsevier B.V.
dc.relation.ispartofPhysiology & Behavior
dc.rightsAcesso restrito
dc.subjecttonin expressionen
dc.subjectnervous systemen
dc.subjectblood pressureen
dc.subjectsaline intakeen
dc.titleTonin expression in the rat brain and tonin-mediated central production of angiotensin IIen