Related Experiment Video
Updated: Aug 12, 2026

Analytical Techniques for Assaying Nitric Oxide Bioactivity
Published on: June 18, 2012
Anti-adrenergic effects of nitric oxide donor SIN-1 in rat cardiac myocytes
M O Stojanovic1, M T Ziolo, G M Wahler
1Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Abstract:
We studied how the nitric oxide (NO*) donor 3-morpholinosydnonimine (SIN-1) alters the response to beta-adrenergic stimulation in cardiac rat myocytes. We found that SIN-1 decreases the positive inotropic effect of isoproterenol (Iso) and decreases the extent of both cell shortening and Ca2+ transient. These effects of SIN-1 were associated with an increased intracellular concentration of cGMP, a decreased intracellular concentration of cAMP, and a reduction in the levels of phosphorylation of phospholamban (PLB) and troponin I (TnI). The guanylyl cyclase inhibitor 1H-8-bromo-1,2,4-oxadiazolo (3,4-d)benz(b)(1,4)oxazin-1-one (ODQ) was not able to prevent the SIN-1-induced reduction of phosphorylation levels of PLB and TnI. However, the effects of SIN-1 were abolished in the presence of superoxide dismutase (SOD) or SOD and catalase. These data suggest that, in the presence of Iso, NO-related congeners, rather than NO*, are responsible for SIN-1 effects. Our results provide new insights into the mechanism by which SIN-1 alters the positive inotropic effects of beta-adrenergic stimulation.
More Related Videos
Related Concept Videos
Nitric Oxide Signaling Pathway
Adrenergic Receptors: β Subtype
Isoprenaline > Adrenaline > Noradrenaline
Neurotransmitter binding to these receptors causes activation of adenylyl cyclase resulting in increased concentrations of cAMP and modulation of calcium ion channels within the cell. They are further classified into β1, β2, and β3 subtypes.
β1-adrenoceptors: β1-adrenoceptors have equal affinities for...
Adrenergic Agonists: Direct-Acting Agents
These agents can be classified...
Adrenergic Antagonists: ɑ and β-Receptor Blockers
Antihypertensive Drugs: Vasodilators
Antianginal Drugs: Nitrates and β-Blockers
Organic nitrates, such as nitroglycerin, play a pivotal role. Once metabolized, they liberate nitric oxide, a molecular marvel. Nitric oxide triggers guanylyl cyclase and augments cGMP production. This biochemical cascade orchestrates the relaxation of vascular smooth muscles, ushering in vasodilation and enhancing coronary blood flow. Administered...

