<prompt> Sympathomimetic drug acting on Dl, D2 and b-1 receptors, but not b-2 receptors -DobutamineDopexamineDopamineIsoprenaline  <response>: Ans. is c i.e., Dopamine o Dopamine acts on dopamine D1 D2 and adrenergic a1 a2 b1 receptors, with no action on b2 receptorso Dobutamine is a relatively selective b1 agonist. Though it acts on both a and b 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 a significant change in HR., BP and Peripheral resistance. 