Contribution of Dopamine in Dopaminergic Neurodegeneration

Abstract

Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive degeneration and loss of nigrostriatal dopaminergic neurons in the midbrain, leading to severe striatal dopamine (DA) depletion resulting in tremor, rigidity, and hypokinesia (Carlsson, 2002). PD is named after James Parkinson who first described the disease as “Shaking Palsy” (Paralysis Agitans) in his classic monograph “An essay on the Shaking Palsy” (Parkinson, 1817). He described the disease as “involuntary tremulous motion, with lessened muscular power, in parts not in action and even when supported; with a propensity to bend the trunk forwards, and to pass from a walking to a running pace: the senses and intellects being uninjured”. Jean-Martin Charcot (1877) gave PD its present name and elaborated on the description of the disease given by James Parkinson (see Elmer, 2005). Descriptions of the symptoms of PD were found mentioned as early as 5000 B.C in the ancient Indian medical treatise “Charakasamhitha” under the name Kampavata (kampa - tremors). It was also found mentioned in the first Chinese medical text, “Nei Jing”, about 2500 years ago, and in an Egyptian text (Garcia Ruiz, 2004). The only major contention presently is the perception of clinicians that in addition to motor impairments, behavioural dysfunction and cognitive impairment too contribute to the morbidity often seen in PD patients