Which neurotransmitter is deficient in Parkinson's disease?

NIMHANS Nursing Officer - 2021

Medical Surgical Nursing

Easy

Appeared in: NIMHANS Nursing Officer - 2021

Explanation

Parkinson's disease is characterized by the progressive death of dopamine-producing (dopaminergic) neurons in the substantia nigra pars compacta, a region in the midbrain.
This neuronal loss leads to a profound deficiency of the neurotransmitter dopamine in the basal ganglia, particularly in the striatum.
Dopamine is essential for regulating motor function, and its absence disrupts the brain's ability to control movement, leading to the classic motor symptoms of the disease.
The severity of motor symptoms, such as tremor, rigidity, and bradykinesia, is directly proportional to the degree of dopamine deficiency.

Option B: While serotonin levels can be reduced in Parkinson's disease, this is not the primary neurotransmitter deficiency responsible for the core motor symptoms. Serotonin depletion is more closely linked to non-motor symptoms like depression, anxiety, and sleep disturbances.
Option C: Acetylcholine is not deficient in Parkinson's disease. In fact, the loss of dopamine creates a relative excess of cholinergic activity. This imbalance between dopamine (inhibitory) and acetylcholine (excitatory) contributes to symptoms, particularly tremor and rigidity.
Option D: GABA (gamma-aminobutyric acid) is the main inhibitory neurotransmitter in the central nervous system and plays a role in the basal ganglia circuitry. However, a deficiency in GABA is not the primary pathological cause of Parkinson's disease. The GABAergic pathways are affected secondary to the loss of dopamine.

Clinical Relevance

Nursing practice connection: Knowing Pathophysiology of Parkinson's disease and associated neurotransmitter deficiency helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
The primary treatment for Parkinson's disease, Levodopa, is a direct consequence of the dopamine deficiency. Nurses must educate patients on the importance of medication timing to manage motor fluctuations.
Nurses monitor for the 'wearing-off' and 'on-off' phenomena associated with long-term Levodopa therapy, which reflect fluctuating dopamine levels and require dose adjustments.
What if the patient develops hallucinations? This can be a side effect of dopamine-enhancing medications. The nursing priority would be to assess for safety, report the symptom to the provider, and anticipate a potential medication adjustment, as excessive dopamine stimulation can cause psychosis.

How to Approach the Question

First, identify the key concepts in the question: 'Parkinson's disease' and 'deficient neurotransmitter'.
This is a factual recall question that tests your knowledge of the pathophysiology of a specific neurodegenerative disorder.
Access your memory bank for the core pathology of Parkinson's. The classic teaching is the loss of dopamine-producing cells.
Evaluate the options based on this core fact. Dopamine is the most direct and correct answer.
Briefly consider the other neurotransmitters to confirm they are incorrect. Recall that acetylcholine is imbalanced (not deficient) and that serotonin/GABA are not the primary cause.

Concept Tested & Keywords

Concept Tested: Pathophysiology of Parkinson's disease and associated neurotransmitter deficiency.
Stem keywords: neurotransmitter, deficient, Parkinson's disease
Lead-in keywords: Which

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