Chronic Absence of Baroreceptors Induces Left Ventricular Dysfunction and Reduced Coronary Blood Flow in Spontaneously Hypertensive Rats

Abstract

Hemodynamic and cardiac morphological variables were measured in normotensive Wistar (N), intacts hypertensive (H) and SHR submitted to sinoaortic denervation (DH) to evaluate the chronic baroreceptor dysfunction on left ventricular (LV) functions and coronary blood flow. Blood (BP) and end-diastolic pressure (PD2) were obtained by direct quantification. The coronary blood flow was measured by the infusion of colored microspheres. The ratio of left ventricular weight to body weight, natriuretic atrial peptide (ANP), alpha-skeletal actin (α-skelectal), alpha and beta myosin heavy chain (α-MHC, β-MHC) genes mRNA expressions were evaluated by real time PCR to assess ventricular hypertrophy. The results were reported as means ± SEM. DH rats did not change BP values compared to H. PD2 of DH (9.91±1.78) was higher than H group (4.30±0.53) while an inverse result regarding coronary blood flow was observed (0.94±0.15 vs 1.80±0.25, respectively). The LV adaptations in DH were higher than in H (2.98 ±0.07 vs 2.15±0.05), as well as the expression of ANP (3.35±0.19 vs 2.39 ± 0.74), β-MHC (3.36±0.18 vs 2.39 ± 0.37). The α-MHC genes expression also were decreased (0.62±0.10 vs 0.79±0.10). Therefore, the chronic absence of baroreflex control by sinoaortic denervation induces left ventricular dysfunction and reduced coronary blood flow in SHR.