Dopamine is catechol in which the hydrogen at position 4 is substituted by a 2-aminoethyl group. It has a role as a cardiotonic drug, a beta-adrenergic agonist, a dopaminergic agent, a sympathomimetic agent, a human metabolite, an Escherichia coli metabolite and a mouse metabolite. It is a conjugate base of a dopaminium(1+).