Related Experiment Video
Updated: May 25, 2026

Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine
Published on: February 9, 2016
Enhancement of myocardial and vascular function after phosphodiesterase-5 inhibition in a rat model
Sivakkanan Loganathan1, Tamás Radovits, Sevil Korkmaz
1Department of Cardiac Surgery, University of Heidelberg, Im Neuenheimer Feld 326, Heidelberg, Germany. sivakkanan.loganathan@googlemail.com
Background:
Recent studies have shown the potential of PDE-5 inhibition on acute and chronic heart failure. Nevertheless it remained unclear, how far load-reducing properties and direct effects on myocardial contractility are responsible for these observations. In the present study, we investigated the effects of vardenafil on myocardial contractility and vascular function in a dose-response study.
Methods:
We performed left ventricular pressure-volume analysis in young adult rats by using a Millar microtip conductance catheter. Pressure-volume loops were recorded before and after intravenous injection of vardenafil (3, 10, 30, 100, 300 μg/kg, n = 6/group).
Results:
Treatment with vardenafil resulted in a significant (p < 0.05) increase in the load-independent cardiac contractility parameters reaching its maximum at the dose of 100μg/kg (ESPVR: 2.15 ± 0.15 vs. 3.29 ± 0.26 mm Hg/μL; PRSW: 93.28 ± 4.04 vs. 134.90 ± 6.27 mm Hg; peak positive dP/dt/EDV: 38.73 ± 7.97 vs. 53.02 ± 3.74 mm Hg·s-1·µL-1; before versus after 100 μg/kg vardenafil). Results of the in vitro organ-bath experiments showed an augmented vasorelaxation of precontracted aortic rings after vardenafil treatment.
Conclusion:
Our data supports the hypothesis that the usage of vardenafil as "inodilators" could have beneficial effects in heart failure patients.
Related Concept Videos
Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
Nitric Oxide Signaling Pathway
Antihypertensive Drugs: Vasodilators
Treatment for Pulmonary Arterial Hypertension: Prostacyclin Receptor Agonists
These agonists bind to the IPR receptor situated on the plasma membrane of the pulmonary artery smooth muscle cells. This binding triggers a cascade of reactions known as the GS-AC-cAMP-PKA pathway. This pathway results in the relaxation of smooth muscle...

