To create a dopamine-deficient (DD) mouse that retains the ability to produce NE, the gene for _______ is selectively restored in noradrenergic neurons.
A) tyrosine hydroxylase
B) 6-hydroxydopamine
C) dopamine β-hydroxylase
D) DOPA

Question

Quizplus · Accepted Answer

Tyrosine hydroxylase is the enzyme responsible for converting tyrosine to L-DOPA, which is the rate-limiting step in the biosynthesis of both dopamine and norepinephrine. By selectively restoring the gene for tyrosine hydroxylase in noradrenergic neurons, the DD mouse can still produce norepinephrine while lacking dopamine. Option B (6-hydroxydopamine) is a toxin that is commonly used to deplete dopamine in animal models, but it is not a gene. Option C (dopamine β-hydroxylase) is only involved in the conversion of dopamine to norepinephrine and would not be sufficient to restore dopamine synthesis. Option D (DOPA) is a precursor molecule that is converted to dopamine via the action of tyrosine hydroxylase, so simply restoring DOPA production would not be sufficient to restore dopamine synthesis.

To Create a Dopamine-Deficient (DD) Mouse That Retains the Ability