<prompt> Bosentan is aan:Serotonin uptakeEndothelin receptor antagonistLeukotriene modifierPhosphodiestease inhibitor  <response>: Endothelin receptors are of 2 types 1.ET A - in smooth muscles 2.ET B - in vascular endothelial cells BOSETAN , macicentan: endothelin receptor antagonists used for the treatment of pulmonary hypeension Ref: KD Tripathi 8th ed 