Arvid Carlsson and His Discoveries

The human brain contains more than a hundred billion nerve cells. They are connected through a complex network of nerve processes. The messages from one nerve cell to another is transmitted through different chemical transmitters. The signal transduction takes place in special points of contact, called synapses.

A nerve cell can have thousands of such contacts with other nerve cells. Arvid Carlsson, a pharmacologist, is best known for his contributions on the neurotransmitter, dopamine. Carlsson was born on January 25, 1923 in Uppsala, Sweden. Carlsson had started Medical school in 1941; however, he withdrew from school for several years to serve in the Swedish armed forces. Finally, in 1951, he finished his M.L. degree. This degree is the equivalent to a M.D. in North America. After finishing he became a professor at the university of Lund. He then moved to Goteborg University in 1959. Carlsson, an accomplished pharmacologist, accompanied by Paul Greengard and Eric Kandel, was awarded for their research in establishing dopamine as a neurotransmitter. In 2000 they received a Nobel Prize for Physiology/ Medicine.

Many of these discoveries have been crucial for a better understanding of the normal functions of the brain. Some discoveries also have help detect disturbances in this signal transduction that can give rise to neurological and psychiatric diseases leading to a new generation of medications. Carlsson conducted a series of studies during the late 1950's, which showed that dopamine is an important transmitter in the brain. Up until this point it was thought that dopamine was only a precursor of another transmitter, noradrenaline. Carlsson developed a measurement that made it possible to calculate tissue levels of dopamine. He found that dopamine was concentrated in other areas of the brain more than noradrenaline, which led him to the conclusion that dopamine is a transmitter.

Dopamine existed in particularly high concentrations in the basal ganglia, which are of importance for the control of motor behavior. In a series of experiments Carlsson used reserpine, which depletes the storage of several synaptic transmitters. According to Yeragani in the article Arvid Carlsson, and the story of dopamine when reserpine was given to experimental animals they lost their ability to perform spontaneous movements. He then treated the animals with L-dopa, a precursor of dopamine, which is transformed to dopamine in the brain. The symptoms disappeared and the animals went back to their normal motor behavior. In other animals that received a precursor of the transmitter serotonin, their motor behavior didn’t improve. During Parkinson's disease, dopamine producing nerve cells in the basal ganglia degenerate, which causes tremors and rigidity. L-dopa, which is converted to dopamine in the brain, compensates for the lack of dopamine and normalizes motor behavior.

Carlsson did not end his investigations there, he showed L-dopa is still one of the most significant use for treatment in Parkinsonism. Apart from the successful treatment of Parkinson's disease Carlsson’s research has increased our understanding of the mechanism of several other drugs. He showed that antipsychotic drugs, mostly used against schizophrenia, affect synaptic transmission by blocking dopamine receptors.

The discoveries of Carlsson have had an incredible impact on the treatment of depression, which is one of our most common diseases. He also significantly contributed to the development of selective serotonin uptake blockers, leading to a new generation of anti-depressive drugs.