title: The effects of catalase inhibition into the fourth cerebral ventricle on the Bezold-Jarisch reflex in spontaneously hypertensive rats.
abstract: Many studies have investigated the role of oxidative stress on cardiovascular system in the brainstem of spontaneously hypertensive rats (SHR). However, we do not know yet if catalase inhibition influences cardiopulmonary reflex (Bezol-Jarisch reflex). Thus, we aimed to evaluate the effects of central catalase inhibition on cardiopulmonary reflex in SHR. Males Wistar Kyoto (WKY) rats and SHR were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. The cardiopulmonary reflex was tested with phenylbiguanide (PBG, 8 μg/kg, bolus, i.v.). Cardiopulmonary reflex was evaluated before and 15 minutes after 3-amino-1,2,4-triazole (ATZ, 0.01 g/100 μL) injection into the 4th V. Vehicle treatment did not change basal MAP and HR and cardiopulmonary reflex responses in SHR and WKY rats. Central ATZ increased hypotensive (p=0.038) responses without influencing the bradycardic reflex (p=0.287) in WKY rats. In SHR, ATZ increased hypotension (p=0.0004) and bradycardic (p=0.04) responses to i.v. PBG. No changes were observed regarding basal MAP and HR after ATZ injection in SHR and WKY rats. We suggest central catalase inhibition affects cardiopulmonary reflex with more intensity in SHR compared to WKY rats.
authors.affiliation: Laboratório de Escrita Científica, Departamento de Morfologia e Fisiologia, Faculdade de Medicina do ABC, Santo André, SP, Brazil. raulcisternas@terra.com.br
authors.forename: José Raul
authors.initials: JR
authors.lastname: Cisternas
authors.forename: Vitor E
authors.initials: VE
authors.lastname: Valenti
authors.forename: Monica A
authors.initials: MA
authors.lastname: Sato
authors.forename: Fernando L A
authors.initials: FL
authors.lastname: Fonseca
authors.forename: Paulo H N
authors.initials: PH
authors.lastname: Saldiva
authors.forename: Carlos B
authors.initials: CB
authors.lastname: De Mello Monteiro
authors.forename: Modesto Leite Rolim
authors.initials: ML
authors.lastname: Neto
authors.forename: Luciano M R
authors.initials: LM
authors.lastname: Rodrigues
authors.forename: Luiz Carlos
authors.initials: LC
authors.lastname: De Abreu
mesh_terms: D000640:Amitrole / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D001645:Biguanides / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D001919:Bradycardia / Q000139:chemically induced*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020546:Fourth Ventricle / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D051381:Rats; D011918:Rats, Inbred SHR / Q000502:physiology; D011921:Rats, Inbred WKY; D012018:Reflex / Q000187:drug effects*; D013997:Time Factors
chemical_list: D000700:Analgesics; D001645:Biguanides; D004791:Enzyme Inhibitors; C008846:phenyl biguanide; D000640:Amitrole