[Pharmacological effect of pentacyanonitrosylferrate and similar complex compounds]

Comparative studies were performed on the spasmolytic and hypotensive effects of pentacyanoferrates with different ligands (NO, NO2, NOS, NH3, H2O) and of hexacyanoferrates and other nitrosyl compounds. Besides sodium nitroprusside, the nitro and thionitro complexes in equimolar doses were found to cause hypotension and relaxation of the aortic strip of rabbits contracted by adrenaline and spasmolytic effects on the contracted guinea pig ileum. The liberated nitrosyl cation or its secondary product, nitrous acid, is thought to be responsible for the pharmacodynamic effects of these complex compounds. This is in agreement with the fact that also other nitrosyl compounds (nitrosyl perchlorate, nitrosyl-bis(dimethylglyoximato)cobaltIII) and free undissociated nitrous acid produce transient spasmolytic effects. Pentacyanoaquoferrate and hexacyanoferrateIII exert, presumably because of the oxydation of sulfhydryl groups, spasmolytic effects in vitro. Accordingly, their effects are prevented in the presence of sulfhydryl compounds such as glutathion or dithioerythrit.