Role of the Nitrergic System of the Cuneiform Nucleus in Cardiovascular Responses in Urethane-Anesthetized Male Rats

• Published in: Iranian journal of medical sciences 2017-09, Vol.42 (5), p.473-480
• Main Authors: Farrokhi, Esmaeil, Shafei, Mohammad Naser, Khajavirad, Abolfazl, Hosseini, Mahmoud, Bideskan, Ali Reza Ebrahimzadeh
• Format: Article
• Language: English
• Subjects: Blood pressure; Cuneiform nucleus; NG-nitro-L-arginine methyl ester; Nitric oxide; Nitroprusside; Original; Rats; Rodents; Urethanes
• ISSN: 0253-0716; 1735-3688

The presence of nitric oxide (NO) in the cuneiform nucleus (CnF) has been previously shown. In this study, NG-nitro-L-arginine methyl ester (L-NAME) (an inhibitor of NO synthase), L-arginine (L-Arg) (a precursor of NO), and sodium nitroprusside (SNP) (a donor of NO) were microinjected into the CnF and cardiovascular responses were investigated. Seventy male rats were divided into 7 groups (n=10 each): 1) saline, 2 and 3) L-NAME (30 and 90 nmol), 4 and 5) L-Arg (20 and 60 nmol), and 6 and 7) SNP (9 and 27 nmol). After anesthesia, the femoral artery was cannulated and cardiovascular parameters were recorded using a PowerLab system. Time course changes in mean arterial pressure (ΔMAP) and heart rate (ΔHR) were calculated and compared with those in the control group (repeated measures ANOVA). Maximum ∆MAP and ∆HR were also compared with those in the control group (independent sample test). ∆MAP with both doses of L-NAME (30: P=0.026 and 90: P=0.007) and ∆HR with the higher dose (P=0.034) were significantly higher than those in the control group. Maximal ∆MAP with both doses (P