Adenosine receptor agonists

General information

To date, four subtypes of adenosine receptor, A ₁ , A _2A , A _2B , and A ₃ , have been described [ ]. Stimulation of specific cell-surface A ₁ receptors shortens the duration, depresses the amplitude, and reduces the rate of rise of the action potential in the atrioventricular node, slowing conduction; this is the mechanism by which adenosine terminates re-entrant supraventricular tachycardias. In myocardial perfusion imaging adenosine causes coronary vasodilatation by stimulating A _2A receptors in vascular endothelium and smooth muscle cells. Stimulation of A _2B receptors in mast cells causes bronchospasm in susceptible individuals. Stimulation of A ₃ receptors reduces the degree of apoptosis resulting from ischemia reperfusion injury in the heart, although most of the cardioprotective effects of adenosine are thought to be mediated by A ₁ receptors. Apadenoson, binodenoson, and regadenoson are new selective adenosine A _2A receptor agonists [ ]. A high proportion of patients experience transient adverse effects after the administration of adenosine; selective agonists developed for clinical use might be safer and would be longer acting.

Drug studies