Question

Parkinson’s disease (PD) is characterized by motor, cognitive, and mood symptoms due to dopamine deficiency. “Parkinsonian personality” has been proposed as a typical feature during the prodromal period – decades before the motor symptoms of PD develop. The pre-PD subjects were shown to exhibit personality described as rigid, introverted, and slow-tempered, did not engage in impulsive behaviors, and tended not to smoke cigarettes or drink alcohol. PD patients are treated with dopamine agonists such as Pramipexole and Ropinirole. A rare side effect is addiction to one’s medications, and/or behavioral addictions such as pathological gambling, compulsive shopping, or hypersexuality.

Answer both questions below, specifying (a) and (b)in your answer.

a) Explain how the reduction in dopaminergic signaling that could precede the development of motor symptoms in PD could explain the “Parkinsonian personality”.

b) Explain the mechanism through which drugs that increase dopaminergic signaling could cause development of addictive syndromes.

Answer 1

a) Studies have confirmed using neuroimaging that elevated dopaminergic neurotransmissionsor signalling is related to high novelty seeking temperaments, that is elevated dopamine responds to rewarding stimulus, whereas, low sensation seeking or"Parkinsonian Personality" is due to low dopaminergic neurotransmissions or signalling.

b) The activation of mesolimbic part in elevated dopaminergic signalling causes feeling of pleasure,these are stored as memories in brain ,these memories called the conditioned associations are responsible for the development of addictive syndrome in PD.