The dopamine receptors are a class of G-protein coupled receptors with dopamine as their endogenous ligand.
D1 receptor
The D1 receptor is coupled to adenylate cyclase via a stimulatory G protein
D2 receptor
The D2 receptor is negatively coupled to adenylate cyclase via an inhibitory G protein
D3 receptor
The D3 receptor is negatively coupled to adenylate cyclase via an inhibitory G protein
D4 receptor
The D4 receptor is negatively coupled to adenylate cyclase via an inhibitory G protein
D5 receptor
The D5 receptor is coupled to adenylate cyclase via a stimulatory G protein