Identification of Mouse Retinal Ganglion Cell Subtypes Through Fluorescent Tracing

Place a retinal tissue isolated from a transgenic mouse with fluorescently labeled retinal ganglion cells, or RGCs, in a recording chamber.

Visual information is relayed to the RGCs, whose axons transmit it to the brain via the optic nerve.

RGC subtypes are distinguished by the branching patterns of their dendrites, which stratify into sublayers within the inner retinal layer.

Flatten the retinal tissue and secure it using a tissue anchor. 

Transfer the chamber onto a microscope stage and perfuse an oxygenated solution to maintain RGC viability.

Using infrared illumination, identify the fluorescent RGCs.

Position a pipette containing a fluorescent tracer onto an RGC. 

Apply positive pressure to prevent clogging.

Switch to negative pressure, drawing the membrane into the pipette to form a seal. 

Apply suction to rupture the membrane, establishing a whole-cell configuration that facilitates tracer diffusion into the dendrites.

Observe the dendritic morphology and stratification to identify the RGC subtypes.