Carlsson, Arvid (1923-) won the 2000 Nobel Prize in physiology or medicine for research on the transmission of nerve impulses. Carlsson shared the prize with American neurobiologist Paul Greengard and Austrian-born American biologist Eric Richard Kandel.

Per Arvid Emil Carlsson was born Jan. 25, 1923, in Uppsala, Sweden. He studied medicine at the University of Lund, receiving M.D. and Ph.D. degrees in 1951. He taught a that university from 1951 to 1959. He then became professor of pharmacology (the science of drugs) at the University of Goteborg, where he remained until retiring in 1989. In 1998, Carlsson Research was formed with Carlsson as its head. The research group has engaged in a number of research and drug development projects in collaboration with large pharmaceutical companies.

In the late 1950's, Carlsson discovered that a chemical called dopamine is one of a group of chemicals called neurotransmitters, which carry information from one nerve cell to another. He found that dopamine acts as a chemical signal that helps control body movement.

His research led to the discovery that a lack of dopamine in certain areas of the brain could disrupt pathways among nerves that control movement. This loss of nerve pathways produces a serious condition known as Parkinson's disease. People with Parkinson's disease experience such symptoms as trembling hands and rigid muscles. Carlsson's discovery led to the use of a drug called levodopa, or L-dopa, to treat Parkinson's disease. L-dopa changes to dopamine in the brain and can often relieve Parkinson's symptoms.

Carlsson made a number of other discoveries that have further clarified the role of dopamine in the brain. His research increased understanding of how several other drugs work, including those used to treat the severe mental disease known as schizophrenia. His discoveries also influenced the great progress in the treatment of depression seen in the late 1900's.