A Novel Nitric Oxide Donor, S-Nitroso-NPivaloyl-D-Penicillamine, Activates a Non-Neuronal Cardiac Cholinergic System to Synthesize Acetylcholine and Augments Cardiac Function.

BACKGROUND/AIMS: In a previous study, we reported that cardiomyocytes were equipped with non-neuronal cardiac cholinergic system (NNCCS) to synthesize acetylcholine (ACh), which is indispensable for maintaining the basic physiological cardiac functions. The aim of this study was to identify and characterize a pharmacological inducer of NNCCS.

METHODS: To identify a pharmacological inducer of NNCCS, we screened several chemical compounds with chemical structures similar to the structure of S-nitroso-N-acetyl-DL-penicillamine (SNAP). Preliminary investigation revealed that SNAP is an inducer of non-neuronal ACh synthesis. We screened potential pharmacological inducers in H9c2 and HEK293 cells using western blot analysis, luciferase assay, and measurements of intracellular cGMP, NO₂ and ACh levels. The effects of the screened compound on cardiac function of male C57BL6 mice were also evaluated using cardiac catheter system.

RESULTS: Among the tested compounds, we selected S-nitroso-Npivaloyl-D-penicillamine (SNPiP), which gradually elevated the intracellular cGMP levels and nitric oxide (NO) levels in H9c2 and HEK293 cells. These elevated levels resulted in the gradual transactivation and translation of the choline acetyltransferase gene. Additionally, in vitro and in vivo SNPiP treatment elevated ACh levels for 72 h. SNPiP-treated mice upregulated their cardiac function without tachycardia but with enhanced diastolic function resulting in improved cardiac output. The effect of SNPiP was dependent on SNPiP nitroso group as verified by the ineffectiveness of N-pivaloyl-D-penicillamine (PiP), which lacks the nitroso group.

CONCLUSION: SNPiP is identified to be one of the important pharmacological candidates for induction of NNCCS.