Celebration of Scholars
Dopaminergic Fibers from the Locus Coeruleus Indirectly Modulate Cerebellar Purkinje Cells through Bergmann Glia Activation
Name:
Nicole McCarthy
Major: Neuroscience
Hometown: Plainfield, IL
Faculty Sponsor:
Other Sponsors: University of Alabama at Birmingham; Dr. Lucas Pozzo-Miller
Type of research: Independent research
Funding: NSF
Abstract
Some key features of Rett
Syndrome (RTT), an autism spectrum disorder, are stereotypic hand movements,
dystonia, and a dyspraxic gait. Since these symptoms all involve motor
coordination, the abnormalities may stem from dysfunction in the cerebellum.
Considering the role of dopamine in motor control, we hypothesize that
dysfunction in dopaminergic signaling in the cerebellum is responsible for
these motor deficits in RTT. Notably, there was limited data on dopaminergic
pathway inputs to the cerebellum. Previous work in our lab shows clear dopamine
expression in the cerebellum, and dopamine receptor type 1 (D1) distributed on
Bergmann glial cells (BGCs) rather than Purkinje cells (PCs), the only neuronal
output of the cerebellum. We aim to determine if dopaminergic fibers from the
substantia nigra pars compacta (SNc) and locus coeruleus (LC) modulates PCs
indirectly by regulating BGCs. We measured protein levels of glutamate AMPA
receptor subunits and their phosphorylated versions by Western immunoblotting.
Using immunohistochemistry (IHC) in brain sections from mice, we observed
dopaminergic fibers originating in the SNc projecting to the cerebellum. By
performing single-molecule fluorescence in situ hybridization (smFISH)
in cerebellar sections, we located D1 receptors in BGCs, but not in PCs,
implying that PCs are indirectly modulated. Future studies include
implementing the deletion of D1 receptors selectively in BGCs to determine the
consequences on motor function.