Dopaminergic neurons in parkinson's disease

Abstract

The discovery of dopamine as a brain neurotransmitter by Arvid Carlsson and colleagues about 50 years ago contributed to better understand some of the brain diseases. Some of the drugs that are most widely used in neurologic and psychiatry illnesses, such as levodopa and antipsychotic drugs, act on dopaminergic mechanism. The discovery that the motor impairments of Parkinson's disease patients improved after restoring the physiological levels of striatal dopamine with levodopa attracted the attention of the neuroscience community for the role of this neurotransmitter in motor and brain functions. In the last decades, the knowledge has also been challenged by evidence that Parkinson's disease also affects cognitive and affective functions. Shortly after the introduction of levodopa as a therapy, a complex set of secondary phenomena such as dyskinesia was observed following repeated administration of the dopamine precursor. Information of dopaminergic cells and circuits has been enriched by findings obtained with several and highly sensitive technology in cellular biology, with sophisticated behavioral analyses of transgenic animals and functional neuroimaging. The present chapter attempts to review results reported in different clinical studies and animal models to provide a comprehensive picture of the role of dopamine in Parkinson's disease. Treatments have successfully been translated from preclinical to pharmacotherapeutic arsenal increasing clinical settings.