The Dopamine Receptors

Abstract Dopamine receptors have a prominent place in our understanding of brain function. Drugs blocking dopamine receptors are used as antipsychotic drugs, drugs activating dopamine receptors as relieving Parkinson disease symptoms. Dopamine receptors have been pharmacologically divided into two classes the receptor that activate and the ones that inhibitory second messenger responses. Molecular cloning approaches have shown that this classification indeed hides not two but five receptors. Of particular importance were the discoveries of two additional inhibitory receptors, because they gave hope for the development of better antipsychotic drugs. But understanding novel receptors discovered on the basis of their sequences presents the challenge to search for their function. Although pharmacological tools are being developed targeting the new dopamine receptors, the engineering of mice lines devoid of these receptors and the studies on the gene expression of these receptors have led our major advances in our renewed understanding of the dopamine system. Key Concepts: Application of homology screening approaches has revolutionised the search for novel G protein‐coupled receptors. Molecular biological approaches can lead to the discovery of pharmacologically unexpected receptors. The new dopamine receptors raised high hopes for the development of new drugs for psychiatric disorders. In spite of the fact that the new dopamine receptors have been discovered approximately 20 years ago, their role in the organism remains mostly not understood. The D 4 dopamine receptors carried out the most hopes for the development of new antipsychotic drugs, it is still viewed as involved in the etiology of attention‐deficit disorders. There is a need for the development of antagonists specific to the new dopamine receptors.