Biochemical Mechanisms by Which Minoxidil Sulfate Influences Mammalian Cells

The study investigated the biochemical mechanisms by which minoxidil sulfate (MxSO₄) induces vasodilation, using rabbit vascular smooth muscle as a model. MxSO₄ relaxed norepinephrine-induced contractions by about 85% but had no effect on KCl-induced contractions. The relaxation effect was inhibited by treatments affecting K⁺ permeability, suggesting that MxSO₄ acts as a K⁺ channel agonist, enhancing K⁺ permeability, leading to hyperpolarization and reduced Ca²⁺ influx, thus causing relaxation. This mechanism was specific to MxSO₄ and not shared by other agents like forskolin or sodium nitroprusside. The study proposed that understanding MxSO₄'s cellular mechanism in vasodilation might help elucidate its hair growth effects, although this connection remained to be explored.