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

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

Author Araujo, R. C. Google Scholar
Lima, M. P. Google Scholar
Lomez, ESL Google Scholar
Bader, M. Google Scholar
Pesquero, J. B. Google Scholar
Sumitani, M. Google Scholar
Pesquero, J. L. Google Scholar
Institution Universidade Federal de Minas Gerais (UFMG)
Univ Mogi Cruzes
MDC Mol Med
Universidade Federal de São Paulo (UNIFESP)
Abstract Tonins 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.
Keywords tonin expression
nervous system
blood pressure
saline intake
Language English
Date 2002-06-01
Published in Physiology & Behavior. Oxford: Pergamon-Elsevier B.V., v. 76, n. 2, p. 327-333, 2002.
ISSN 0031-9384 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 327-333
Access rights Closed access
Type Article
Web of Science ID WOS:000176591400020

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