Bidirectional Neuronal Actuation by Uncaging with Violet and Green Light.

Area of Science:

• Photochemistry
• Neuroscience
• Molecular Biology

Background:

• Precise control over chemical signaling in biological systems is crucial for understanding complex cellular processes.
• Existing uncaging techniques often lack wavelength selectivity, limiting the ability to probe multiple pathways simultaneously.

Purpose of the Study:

• To develop a novel photochemical protecting group enabling wavelength-selective uncaging using distinct light colors.
• To demonstrate the orthogonal control of neuronal activity using green and violet light.

Main Methods:

• Synthesis of thio-coumarin-102 as a new chromophore with a high absorption ratio.
• Photolysis of thio-coumarin-102 caged gamma-aminobutyric acid and coumarin-102 caged glutamate on neurons.
• Whole-cell patch-clamp recordings and 3D calcium imaging to assess neuronal responses.

Main Results:

• Thio-coumarin-102 exhibited high wavelength selectivity for uncaging, with >100-fold difference in neuronal responses between green and violet light.
• Orthogonal control of neuronal action potentials was achieved by selectively uncaging glutamate (violet light) and gamma-aminobutyric acid (green light).
• Independent function of dendritic inputs was confirmed through localized irradiation and calcium imaging.

Conclusions:

• The developed (thio)-coumarin-102 caged compounds provide a powerful tool for wavelength-selective uncaging.
• This method allows for simultaneous and independent interrogation of two distinct chemical signaling pathways in living cells.
• Enables advanced studies on neuronal circuit function and complex cellular signaling.