Dopamine (DA, a contraction of 3,4-dihydroxyphenethylamine) is a neuromodulatory molecule that plays several important roles in cells. It is an organic chemical of the catecholamine and phenethylamine families. It is an amine synthesized by removing a carboxyl group from a molecule of its precursor chemical, L-DOPA, which is synthesized in the brain and kidneys. Dopamine is also synthesized in plants and most animals. In the brain, dopamine functions as a neurotransmitter—a chemical released by neurons (nerve cells) to send signals to other nerve cells. 

In the present book, twelve typical literatures about dopamine published on international authoritative journals were selected to introduce the worldwide newest progress, which contains reviews or original researches on dopamine. We hope this book can demonstrate advances in dopamine as well as give references to the researchers, students and other related people.