Nitric oxide modulates the frog heart ventricle morphodynamics

作者：Acierno Raffaele; Gattuso Alfonsina^*; Guerrieri Antonio; Mannarino Cinzia; Amelio Daniela; Tota Bruno

来源：Comparative Biochemistry and Physiology A-Molecular & Integrative Physiology, 2008, 151(1): 51-60.

DOI：10.1016/j.cbpa.2008.05.012

• avascular heart
• end-systolic volume
• ejection fraction
• end-diastolic volume
• myocardial relaxation
• nitric oxide
• ventricular morphodynamics

The aim of this work was to investigate in the avascular heart of the frog Rana esculenta the influence of nitric oxide (NO) on ventricular systolic and diastolic functions by using a novel image analysis technique. The external volume variations of the whole ventricle were monitored during the heart cycle by video acquisition (visible light) and analysed by an appropriately developed software with a specific formula for irregular convex solids. The system, which measures the rate of volume changes and the ejection fraction, directly determined the volumetric behaviour of the working frog heart after stimulation or inhibition of NOS-NO-cGMP pathway. End-diastolic volume (EDVext), end-systotic volume (ESVext), contraction and relaxation velocities (dV/dt(sys) and dV/dt(dia), respectively), stroke volume (SV) and ejection fraction (EF), were measured before and after perfusion with NOS substrate (L-arginine), NO donor (SIN-1), cGMP analogue (8-Br-cGMP), NOS inhibitors (N-G-monomethyl-L-arginine, L-NMMA; L-N(5)-(1-iminoethyl)-ornithine, L-NIO: 7-Nitroindazole, 7-NI) and guanylyl cyclase inhibitor (ODQ). The results showed that NO reduces ventricular systolic function improving diastolic filling, while NOS inhibition increases contractility impairing ventricular filling capacity. The presence of activated eNOS (p-eNOS)was Morphologically documented, further supporting that the mechanical activity of the ventricular pump in frog is influenced by a tonic release of NOS-generated NO.

• 出版日期2008-9