title: Effects of the administration of a catalase inhibitor into the fourth cerebral ventricle on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke.
abstract: OBJECTIVE
  Previous studies have demonstrated a relationship between brain oxidative stress and cardiovascular regulation. We evaluated the effects of central catalase inhibition on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke.
  
  
  METHODS
  Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SH) (16 weeks old) were implanted with a stainless steel guide cannula leading into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for arterial pressure and heart rate measurement and drug infusion, respectively. The rats were exposed to sidestream cigarette smoke for 180 minutes/day, 5 days/week for 3 weeks (CO: 100-300 ppm). The baroreflex was tested using a pressor dose of phenylephrine (8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (50 μg/kg, bolus). Cardiovascular responses were evaluated before and 5, 15, 30 and 60 minutes after injection of a catalase inhibitor (3-amino-1,2,4-triazole, 0.001 g/100 μL) into the 4th V.
  
  
  RESULTS
  Vehicle administration into the 4th V did not affect the cardiovascular response, whereas administration of the central catalase inhibitor increased the basal HR and attenuated the bradycardic peak (p<0.05) to a greater extent in WKY rats exposed to sidestream cigarette smoke than in WKY rats exposed to fresh air. However, in spontaneously hypertensive rats, the effect of the catalase inhibitor treatment was stronger in the fresh air condition (p<0.05).
  
  
  CONCLUSIONS
  Administration of a catalase inhibitor into the 4th V combined with exposure to sidestream cigarette smoke has a stronger effect in WKY rats than in SH rats.
authors.affiliation: Universidade Estadual Paulista, Faculdade de Ciências e Tecnologia, Programa de Pós-Graduação em Fisioterapia, Presidente Prudente/SP, Brasil. vitor.valenti@gmail.com
authors.forename: Vitor E
authors.initials: VE
authors.lastname: Valenti
authors.forename: Luiz Carlos de
authors.initials: LC
authors.lastname: Abreu
authors.forename: Fernando L A
authors.initials: FL
authors.lastname: Fonseca
authors.forename: Fernando
authors.initials: F
authors.lastname: Adami
authors.forename: Monica A
authors.initials: MA
authors.lastname: Sato
authors.forename: Luiz Carlos M
authors.initials: LC
authors.lastname: Vanderlei
authors.forename: Lucas Lima
authors.initials: LL
authors.lastname: Ferreira
authors.forename: Luciano M
authors.initials: LM
authors.lastname: Rodrigues
authors.forename: Celso
authors.initials: C
authors.lastname: Ferreira
mesh_terms: D000640:Amitrole / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D062186:Arterial Pressure / Q000187:drug effects; D017704:Baroreflex / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects*; D002374:Catalase / Q000037:antagonists & inhibitors*; D004791:Enzyme Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D020546:Fourth Ventricle / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D017382:Reactive Oxygen Species / Q000378:metabolism; D012016:Reference Values; D013045:Species Specificity; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*
chemical_list: D004791:Enzyme Inhibitors; D017382:Reactive Oxygen Species; D014028:Tobacco Smoke Pollution; D002374:Catalase; D000640:Amitrole