The weaver mutant mouse as a model of nigrostriatal dysfunction

Area of Science:

• Neuroscience
• Genetics
• Pharmacology

Background:

• The weaver mutant mouse presents a genetic defect leading to substantial dopamine neuron loss.
• This degeneration primarily affects the nigrostriatal pathway, a critical component of motor control.
• Early onset of dopamine system deficits is observed as early as postnatal day 3.

Purpose of the Study:

• To investigate the neurochemical alterations in the weaver mutant mouse model.
• To explore the compensatory mechanisms within the dopaminergic and other neurotransmitter systems.
• To characterize the weaver mouse as a model for naturally occurring neuronal degeneration.

Main Methods:

• Analysis of striatal tyrosine hydroxylase and dopamine content.
• Measurement of dopamine uptake capacity.
• Assessment of in vitro resting and amphetamine-evoked dopamine release.
• Quantification of serotonin content in the striatum.

Main Results:

• Striatal dopamine and tyrosine hydroxylase levels were reduced by 60-70%.
• Dopamine uptake was impaired by up to 95%.
• Elevated resting and evoked dopamine release, along with increased striatal serotonin, suggest compensatory adaptations.

Conclusions:

• The weaver mouse displays significant deficits in the nigrostriatal dopamine system.
• Adaptive changes in dopaminergic and serotonergic systems may functionally compensate for dopamine loss.
• This model offers a valuable tool for studying neuronal degeneration distinct from induced models.