Dobutamine mainly act at this receptor:

(Ref: Katzung, 14th ed. pg. 149; KDT, 6th ed. pg. 126)Dobutamine is a relatively selective b1 agonist. Though it acts on both alpha and beta receptors, the only prominent action of clinically employed doses is its b1 action, i.e. an increase in force of cardiac contraction and output without significant change in HR, BP or peripheral resistance.Use: Heart failure (as an ionotrope)