Aporphines

Apomorphine, sold under the brand name Apokyn among others, is a type of aporphine that functions as a non-selective dopamine agonist which activates both D2-like and, to a much lesser extent, D1-like receptors. It also acts as an antagonist of 5-HT2 and α-adrenergic receptors with high affinity. The compound is an alkaloid belonging to nymphaea caerulea, or blue lotus, but is also historically known as a morphine decomposition product made by boiling morphine with concentrated acid, hence the -morphine suffix. Contrary to its name, apomorphine does not actually contain morphine or its skeleto

Chloroethylnorapomorphine is a chemical once thought to be an irreversible dopamine D2 receptor antagonist; however, it was later proved to be reversible.