The dopamine D2-, D3-, D4 receptor
There are two main subgroups of dopamine receptor – D1-like and D2-like. The D2-like family contains the D2, D3 and D4 subtypes and the D1-like receptor family contains the D1 and D5 receptor subtypes. The D2-like receptors are found throughout the brain and in smooth muscle and presynaptic nerve terminals. Coupled to inhibitory G-proteins, dopamine D2-like receptors have an inhibitory effect on neurotransmission when bound by an agonist. Many neuroleptic drugs are antagonists of the D2 receptors. This class of drug is used to treat psychotic disorders, such as schizophrenia.
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References
Other transmitters and modulators. In: Pharmacology, 4th edition. Rang HP, Dale MM and Ritter JM. Edinburgh, UK: Harcourt Publishers Ltd, 2001:483–499.
Introduction to autonomic pharmacology. In: Basic and clinical pharmacology, 8th edition. Katzung BG. USA: The McGraw Hill Companies, Inc, 2001:75–91.