Dopamine Receptors, Their Types and Location

Dopamine receptors have five Types:

D1
D2
D3
D4
D5


D1 and D5 Receptors are excitatory, and activate adenylyl cyclase and often excite neurons
D2, D3 and D4 are inhibitory and inhibit neurotransmission. It inhibit adenylyl cyclase and induce hyperpolarizaion by opening K+ channels.

Location of D1 Receptors:
                                        Smooth muscles of pulmonary artery, kidney, smooth muscles of various organs e.g  sphincters of stomach., proximal tubule of nephron, brain


Location of D2 receptors::
                                        Brain, Substantia nigra, neostraital pathway, pulmonary artery, kidney
Location of D3,D4,D5:
                                        These are primarily present in brain. D4 receptors are expressed in atrial wall.  dopamine increases myocardium contractility.