title: Presentation of an experimental method to induce in vitro ("organ chambers") respiratory acidosis and its effect on vascular reactivity.
abstract: OBJECTIVE
  To create in vitro a model to generate acidosis by CO2 bubbling "organ chambers", which would be useful for researchers that aim to study the effects of acid-base disturbs on the endothelium-dependent vascular reactivity.
  
  
  METHODS
  Eighteen male Wistar rats (230-280 g) were housed, before the experiments, under standard laboratory conditions (12h light/dark cycle at 21°C), with free access to food and water. The protocol for promoting in vitro respiratory acidosis was carried out by bubbling increased concentrations of CO2. The target was to achieve an ideal way to decrease the pH gradually to a value of approximately 6.6.It was used, initially, a gas blender varying concentrations of the carbogenic mixture (95% O2 + 5% CO2) and pure CO2.
  
  
  RESULTS
  1) 100% CO2, pH variation very fast, pH minimum 6.0; 2) 90%CO2 pH variation bit slower, pH minimum 6.31; 3) 70%CO2, pH variation slower, pH minimum 6.32; 4) 50% CO2, pH variation slower, pH minimum 6:42; 5) 40 %CO2, Adequate record, pH minimum 6.61, and; 6) 30 %CO2 could not reach values below pH minimum 7.03. Based on these data the gas mixture (O2 60% + CO2 40%) was adopted.
  
  
  CONCLUSIONS
  This gas mixture (O2 60% + CO2 40%) was effective in inducing respiratory acidosis at a speed that made, possible the recording of isometric force.
authors.affiliation: Department of Surgery and Anatomy, Ribeirao Preto School of Medicine, University of Sao Paulo, Brazil.
authors.forename: Tales Rubens de
authors.initials: TR
authors.lastname: Nadai
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Ana Paula Cassiano
authors.initials: AP
authors.lastname: Silveira
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Ariadne Santana e Neves
authors.initials: AS
authors.lastname: Monteiro
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Debora Ribeiro
authors.initials: DR
authors.lastname: Campos
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Marco Tulio Rezende de
authors.initials: MT
authors.lastname: Carvalho
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Agnes Afrodite Sumarelli
authors.initials: AA
authors.lastname: Albuquerque
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Andrea Carla
authors.initials: AC
authors.lastname: Celotto
authors.affiliation: Department of Surgery and Anatomy, FMRP, USP, Ribeirao Preto, SP, Brazil.
authors.forename: Paulo Roberto Barbosa
authors.initials: PR
authors.lastname: Evora
mesh_terms: D000142:Acidosis, Respiratory / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D000818:Animals; D001784:Blood Gas Analysis; D002245:Carbon Dioxide / Q000737:chemistry / Q000378:metabolism*; D004195:Disease Models, Animal; D004730:Endothelium, Vascular / Q000737:chemistry / Q000378:metabolism* / Q000503:physiopathology; D045462:Endothelium-Dependent Relaxing Factors / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008297:Male; D017208:Rats, Wistar; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D045462:Endothelium-Dependent Relaxing Factors; D002245:Carbon Dioxide