Conserved role of dopamine in the modulation of behavior

Abstract

Dopamine is an ancient signaling molecule. It is responsible for maintaining the adaptability of behavioral outputs and is found across taxa. The following is a summary of the role of dopamine and the mechanisms of its function and dysfunction. We discuss our recent findings on dopaminergic control of behaviors in C. elegans and discuss its potential implications for work in the fields of C. elegans and Parkinson research.

Keywords: Caenorhabditis elegans; Parkinson’s disease; gait transitions.

Figure 1. Synthesis pathway for dopamine. Dopamine is primarily synthesized by tyrosine hydroxylase (A) but can also be made in its absence (B).

Figure 2. Evolutionary tree showing the presence of dopamine across different taxa as well as its use. Dopamine seems to be generally involved in the production of slower gaits often associated with feeding.

Figure 3. The dopaminergic system is required for swim to crawl transitions in C. elegans. The crawling frequency before and after swimming was compared for worms with impairments in their aminergic systems. Only worms deficient in dopamine production, or in the D1-like dopamine receptor pathway showed a significantly marked deficit transitioning from swimming to crawling. Behavioral assay showing the ratio of crawling head bends following swimming to that before swimming. The assay includes all available bioaminergic pathway C. elegans mutants. Bars report means and SEMs.