Detecting Physiological Responses from Sensory Neurons in Drosophila

Attach an anesthetized genetically modified Drosophila melanogaster on its side to a coverslip.

Extend its forelegs and secure them to expose the tarsal segments.

These segments have gustatory neurons expressing calcium indicator complexes that fluoresce in calcium-bound form.

Draw a hydrophobic barrier around the fly to retain the solution.

Allow the fly to recover and overlay a buffered saline solution onto the exposed tarsal segments to moisten them.

Under a confocal microscope, observe tarsal segments and image the gustatory neurons at various depths to obtain a pre-stimulation fluorescence.

Add a stimulation solution containing lipophilic ligands onto the segment.

These ligands bind to the gustatory neuron receptors, initiating signaling pathways and triggering the opening of calcium channels.

This allows calcium ions from the extracellular fluid to enter the cytoplasm and bind to the calcium indicator complexes, resulting in fluorescence emission.

When observed again, an increase in neuronal fluorescence confirms the neuronal physiological response to the ligand.