Distribution of Dopamine Receptors

Dopamine neurotransmission has a very broad clinical relevance because of its alteration in several prevalent psychomotor disturbances (see Chapter 15 for more details). The most frequently occurring dopaminergic dysfunction is associated with Parkinson’s disease, caused by the progressive loss of the dopaminergic neurons of the substantia nigra (1). Although the etiology of affective psychoses, addictions to cocaine or alcohol, and hypertension are less well understood, a large body of clinical and experimental observations document that changes occur in dopamine mechanisms in these disorders (2,3). One of the prevalent treatments for dopaminergic dysfunctions is the use of exogenous dopamine replacement/attenuation therapies in modern neurology and psychiatry to activate/block dopamine receptors. This type of intervention is prescribed whether or not the dopaminergic system has a direct etiology for the disorder, for example, Huntington’s disease (4), schizophrenia (5), addiction (6), and stress (7) in addition to the well-established regimen of L-DOPA precursor treatment for amelioration of the symptoms associated with Parkinson’s disease.