Dopaminergic abnormalities in Hdac6-deficient mice

Area of Science:

• Neuroscience
• Molecular Biology
• Psychiatry

Background:

• Histone deacetylase 6 (Hdac6) is abundant in the brain and influences emotional behaviors.
• Dopamine signaling, mediated by D1-like and D2-like receptors, is crucial for movement, cognition, and motivation.
• Dysfunction in dopamine pathways is implicated in various psychiatric disorders.

Purpose of the Study:

• To investigate the dopaminergic abnormalities in Hdac6 knockout (KO) mice.
• To elucidate the molecular mechanisms linking Hdac6 to dopamine system function and psychiatric disorders.

Main Methods:

• Behavioral analysis of Hdac6 KO mice in response to novel environments and psychostimulants.
• Assessment of locomotor activity following administration of dopamine receptor agonists and apomorphine.
• Analysis of Hdac6 expression in dopaminergic neurons and acetylation levels of synaptosomal proteins.
• Measurement of striatal dopamine and its metabolites, and D2 dopamine receptor mRNA levels in Hdac6 KO mice.

Main Results:

• Hdac6 KO mice exhibited increased locomotor responses to novel environments and psychostimulants.
• These mice showed enhanced sensitivity to D2-like dopamine receptor agonists and apomorphine.
• Hdac6 depletion increased acetylation of dopamine-related synaptosomal proteins and decreased striatal D2 dopamine receptor mRNA levels.
• Basal levels of dopamine and its metabolites remained normal in Hdac6 KO mice.

Conclusions:

• Hdac6 deficiency leads to aberrant dopamine-dependent behaviors through enhanced postsynaptic dopamine D2 receptor signaling.
• Hdac6 and protein acetylation are implicated in the regulation of D2 dopamine receptor signaling.
• These findings suggest a potential role for Hdac6 in the pathology of dopamine-related psychiatric disorders like schizophrenia.