Document Detail

Tonin expression in the rat brain and tonin-mediated central production of angiotensin II.
MedLine Citation:
PMID:  12044607     Owner:  NLM     Status:  MEDLINE    
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.
Ronaldo C Araujo; Mercia P Lima; Eliane S L Lomez; Michael Bader; Joao B Pesquero; Marie Sumitani; Jorge L Pesquero
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Physiology & behavior     Volume:  76     ISSN:  0031-9384     ISO Abbreviation:  Physiol. Behav.     Publication Date:  2002 Jun 
Date Detail:
Created Date:  2002-06-04     Completed Date:  2002-09-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0151504     Medline TA:  Physiol Behav     Country:  United States    
Other Details:
Languages:  eng     Pagination:  327-33     Citation Subset:  IM    
Department of Physiology and Biophysics, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte, Brazil.
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MeSH Terms
Actins / biosynthesis
Angiotensin II / biosynthesis*
Astrocytes / metabolism
Blood Pressure / drug effects,  physiology
Brain Chemistry / drug effects,  physiology*
Drinking Behavior / drug effects
Injections, Intraventricular
Mesencephalon / cytology,  drug effects,  metabolism
Nuclease Protection Assays
Rats, Wistar
Reverse Transcriptase Polymerase Chain Reaction
Serine Endopeptidases / biosynthesis*,  pharmacology*
Tissue Kallikreins / biosynthesis*,  pharmacology*
Urodynamics / drug effects
Reg. No./Substance:
0/Actins; 11128-99-7/Angiotensin II; EC 3.4.21.-/Serine Endopeptidases; EC 3.4.21.-/tonin; EC Kallikreins

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