Question

The first signs of neurodegeneration in Huntington's disease involve loss of?

1) neurons involved in the synthesis of nitrous oxide
2) dopamine-secreting neurons of the nigrostriatal system
3) neurons involved in glucose metabolism
4) GABAergic neurons of the putamen
5) cholinergic neurons in the pons

Answer 1

The first signs of neurodegeneration in Huntington's disease involve the loss of GABAergic neurons in the putamen, due to a genetic mutation affecting the huntingtin protein, impacting calcium regulation and leading to symptoms like involuntary movements and cognitive decline.

Step-by-step explanation:

Huntington's Disease Neurodegeneration

The first signs of neurodegeneration in Huntington's disease involve the loss of GABAergic neurons of the putamen. These neurons are a specific type of neuron known as GABAergic medium-sized spiny neurons and play a crucial role in the motor and cognitive functions of the brain. As Huntington's disease progresses, the degeneration of these neurons leads to a range of physical, psychological, and cognitive symptoms such as involuntary movements, difficulties with voluntary movement control, and cognitive decline. The disease is caused by a genetic mutation resulting in a longer than normal sequence in the huntingtin protein, which is believed to disrupt normal cellular processes and lead to neuron cell death, particularly affecting calcium regulation and mitochondrial function.

While Huntington's disease pathology is primarily characterized by loss of GABAergic neurons in the striatum, the degeneration of dopaminergic neurons is a hallmark of Parkinson's disease, particularly in the substantia nigra region of the brain. Parkinson's disease also presents with motor symptoms, but these are due to different underlying mechanisms and involve issues with the dopamine neurotransmitter system.

Answer 2

The first signs of neurodegeneration in Huntington's disease involve the loss of GABAergic neurons in the putamen, corresponding to option 4.

Step-by-step explanation:

Huntington's disease is characterized by progressive neurodegeneration, particularly affecting the striatum, including the putamen. In the early stages, there is a selective loss of GABAergic neurons in the putamen, leading to imbalances in neurotransmitter signaling. GABAergic neurons play a crucial role in inhibitory neurotransmission, and their dysfunction contributes to the motor and cognitive symptoms observed in Huntington's disease. While other neurotransmitter systems, such as dopamine and glutamate, are also affected later in the disease, the initial signs involve the GABAergic neurons in the putamen.

Option 4 is the answer, accurately identifying the loss of GABAergic neurons in the putamen as the early signs of neurodegeneration in Huntington's disease.