text: Prostaglandin E1, E2, << STA2 >> (a stable analogue of thromboxane A2), 17-phenyl-trinor-PGE2 (an EP1-selective agonist) and sulprostone (an EP3-selective agonist) inhibited the HVA Ca2+ current (HVA ICa) dose-dependently, and the rank order of potency to inhibit [[ HVA Ca2+ channels ]] was sulprostone>PGE2, PGE1>STA2>>17-phenyl-trinor-PGE2.