| Popis: |
Neurons communicate through chemical signaling molecules that may diffuse beyond their point of release in axon terminals and modulate the activity of larger neuronal networks in a process known as volume transmission. Molecules such as dopamine belong to this class of diffusive neurotransmitters. In addition to canonical release from axonal arbors, somatodendritic dopamine release constitutes an important signaling mechanism for dopamine neurons. However, the spatiotemporal dynamics as well as regulatory mechanisms of somatodendritic release have not been adequately explored, and it is not clear if release arises from soma or dendrites. These gaps in our understanding of somatodendritic dopamine efflux are driven in large part by the inability of current assays to measure neurochemical effluxes at requisite spatial and temporal scales. To address this, we developed DopaFilm, a 2-dimensional chemi-sensitive surface on which primary dopamine neuron cultures can be grown. DopaFilm is developed by drop-casting a solution of single strand DNA functionalized single wall carbon nanotube-based catecholamine sensors (NIRcat) onto glass substrates and passivating the surfaces with poly-lysine. DopaFilm enabled recording of dopamine efflux with exquisite sub-cellular resolution and millisecond temporal resolution. When deployed in perikaryal of dopamine neurons, DopaFilm reveals that somatodendritic effluxes of dopamine primary arise from dendrites and not from the soma. Coupled with immunofluorescence and super resolution imaging, our work affords explorations of the regulatory mechanism of dendritic dopamine release, as well as shed light on the spatiotemporal dynamics and heterogeneities associated with dendritic release. |
