Effects of catalase inhibition into the fourth cerebral ventricle on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke

• Grant number: 13/02171-7
• Support Opportunities: Regular Research Grants - Publications - Scientific article
• Start date: April 01, 2013
• End date: September 30, 2013
• Field of knowledge: Health Sciences - Medicine - Medical Clinics
• Principal Investigator: Vitor Engrácia Valenti
• Grantee: Vitor Engrácia Valenti
• Host Institution: Faculdade de Filosofia e Ciências (FFC). Universidade Estadual Paulista (UNESP). Campus de Marília. Marília , SP, Brazil

Abstract

OBJECTIVE: The literature demonstrated the relationship between brain oxidative stressand cardiovascular regulation. We aimed to evaluate the effects of central catalaseinhibition on cardiovascular responses in spontaneously hypertensive rats (SHR) exposedto sidestream cigarette smoke (SSCS). METHODS: Males Wistar Kyoto rats (WKY) andSHR (16 weeks old) were implanted with a stainless steel guide cannula into the fourthcerebral ventricle (4thV). Femoral artery and vein were cannulated for mean arterialpressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Ratswere exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm).Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 ¼g/kg, bolus) and adepressor dose of sodium nitroprusside (SNP, 50 ¼g/kg, bolus). Cardiovascular responseswere evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalaseinhibitor, 0.001g/100¼L) injection into the 4th V. RESULTS: Vehicle treatment into the 4thV did not change cardiovascular responses. Central catalase inhibition increased basal HRand attenuated bradycardic peak (p<0.05) with more intensity in WKY rats exposed toSSCS compared to WKY rats exposed to fresh air. However, Catalase inhibition into the 4thV increased the same variables with more intensity in SHR exposed to fresh air (p<0.05).CONCLUSION: We suggest that catalase inhibition into the 4th V has stronger effects onWKY rats exposed to SSCS, which is not observed in SHR. (AU)