Trigonelline hydrochloride is extracted from the seeds of Trigonellafoenum-graecumL.

Pinardil (P-1134, S-1230) is a guanidine that opens potassium channels and directly dilates peripheral blood vessels in small arteries, lowering blood pressure and peripheral resistance and producing fluid retention.

OR-1896 is the active metabolite of Levosimendan, a highly specific phosphodiesterase (PDE III) inhibitor, a vasodilator with partial anti-inflammatory properties that produces vasodilation in different types of blood vessels through activation of ATP-sensitive (KATP) and other potassium channels.