Samantha Van Brocklin
Research Mentor: Jacqueline Seddon
Mentor Department: Neuroscience Graduate Program, MCDB, Medicine
Author(s): Samantha Van Brocklin, Jackie Seddon, Paul Kramer
Session: Session 6 (3:00 PM – 3:50 PM)
Presentation Type: Poster 89
Abstract
The dopaminergic mesolimbic system is important in reward signaling and motivated behaviors. Dopamine signals reward as it is released in response to a rewarding cue. Dopamine axons project from the ventral tegmental area (VTA) to the nucleus accumbens (NAc). These axons propagate action potentials very quickly but, interestingly, they are unmyelinated. Ankyrin G is a scaffolding protein concentrated in the axon initial segment of neurons. This region is responsible for generating action potentials as there is a large amount of voltage-gated sodium channels present. It is also responsible for regulating firing rates and neuronal plasticity making it very important for dopamine signaling. Ankyrin B is a scaffolding protein for ion channels located in the distal part of the axon. The length and expression of these proteins in the axon is unknown, but their expression is critical to the propagation of action potentials. Addictive substances like nicotine “hijack†our brain’s reward system and alter our response to typical rewarding cues as use changes how dopamine is released in our system. Furthermore, there is not much known about how the expression of Ank G and Ank B are changed following the consumption of nicotine. Understanding these proteins will aid in understanding how dopamine release is changed when our brain undergoes different processes like addiction. In order to see the expression of the proteins Ank G and Ank B in relation to the cell bodies and axons of dopamine neurons, immunohistochemistry with fluorescent antibodies was performed. Results from these experiments indicate that these proteins appear in “puncta†along the axons and around the cell bodies which demonstrates that they are helping action potentials propagate. Further experiments will show if there are consistencies with these findings as well as how this may change following the consumption of nicotine.
