Pharmacology Cholinergic drug which acts on heart by decrease in levels of cAMP and due to opening of K+ channels is- A Methacholine B Oxotremorine C Bethanechol D DMPP 💡 Explanation Cholinergic drug which acts on heart by decrease in levels of cAMP and due to opening of K+ channels is- ✓ Correct Answer: A. Methacholine