Localization of Dopamine Receptors in the Brain of Midshipman Fish by Visualization of Fluorescent Dopamine Receptor Ligands

Amanda J. MillerMiller
Advisor - J. Matthew Kittelberger

Porichthys notatus, or Plainfin Midshipman fish, are characterized by vocalizations that are essential for courtship and reproductive success. Type I males have specialized brain circuitry that is involved in the production of humming sounds. The neurotransmitter dopamine may be involved in modulating reward, motivation and motor control for reproductive humming behaviors in these brain regions. It was hypothesized that dopamine receptors would be located in brain regions associated with vocalization. In this study, we used two fluorescent dopamine receptor ligands (Dansyl labeled dopamine and 3-Bodipy-propanoic Acid N-Phenethylspiperone Amide) to identify the distribution of dopamine receptors in midshipman brains. Brains were sliced, sectioned onto slides and incubated after 24 hours with a fluorescent ligand, or with a fluorescent ligand plus a nonfluorescent competitor ligand. Although certain brain areas fluoresced after incubation, indicating receptor binding, fluorescence did not observably decrease once the fluorescent ligands were competed with a nonfluorescent ligand. This indicates that the ligand binding is most likely nonspecific to dopamine receptors, which prevents us from drawing concrete conclusions about dopamine receptor distribution in midshipman brains.