2. Dopamine receptors—

Each dopamine receptor is G protein-coupled and contains 7 transmembrane domains. The D2 receptor, found in the caudate putamen, nucleus accumbens, cerebral cortex, and hypothalamus, is negatively coupled to adenylyl cyclase. The therapeutic efficacy of the older antipsychotic drugs correlates with their relative affinity for the D2 receptor. Unfortunately, there is also a correlation between blockade of D2 receptors and extrapyramidal dysfunction.