Prostaglandins induce the diffusion of platelets, provoke the constriction or dilation of smooth myocytes in vessels, desensitize certain neurons (neural cells) to pain, are eicosanoids that ligate G-coupled protein receptors in the plasmalemmat cells, preventing certain substances from entering the cells, inhibit the initiation of parturition (birth), and are hormones that reach their targets via transport in the bloodstream.