Soluble guanylate cyclase (sGC), a receptor for nitric oxide (NO), is a heterodimer consisting of alpha and beta subunits, with the beta subunit featuring a heme-nitric oxide (H-NOX) binding domain. The binding of NO to H-NOX induces sGC to generate the second messenger cGMP. BAY 41-2272 is a pyrazolopyridine compound that acts as an activator of sGC, stimulating activity to a level that would be expected to cause biologically important increases in cGMP at concentrations as low as 10-100 nM. Through this effect, it inhibits platelet aggregation (IC50 = 36 nM), induces relaxation of phenylephrine-preconstricted rabbit aorta rings (IC50 = 304 nM), and reduces proliferation in smooth muscle. BAY 41-2272 is effective in vivo, as it decreases mean arterial blood pressure in hypertensive rats. Unlike another sGC activator, YC-1 , BAY 41-2772 does not inhibit phosphodiesterases.
