adenosine (purinergic agonist)
- acts on A1 receptor of AV node
- decreases cAMP levels, therefore blocks Ca2+ current due to decreased phosphorylation of Ca2+ channel.
- Enhances K+ conductance, causes hyperpolarization
- decreases conducton velosity, increases ERP in AV node
- slows rate of rise of pacemaker potential
- SE: flushing and hypotension, paresthesias, SOB, chest pain (bronchospasm)