Photopharmacological modulation of hippocampal local field potential by caged-glutamate with MicroLED probe.

Aim: Photopharmacology is a new technique for modulating biological phenomena through the photoconversion of substances in a specific target region at precise times. Caged compounds are thought to be compatible with photopharmacology as uncaged ligands are released and function in a light irradiation-dependent manner. Here, we investigated whether a microscale light-emitting diode (MicroLED) probe is applicable for the photoconversion of caged-glutamate (caged-Glu) in vivo.
Methods: A needle-shaped MicroLED probe was fabricated and inserted into the mouse hippocampal dentate gyrus (DG) with a cannula for drug injection and a recording electrode for measuring the local field potential (LFP). Artificial cerebrospinal fluid (ACSF) or caged-Glu was infused into the DG and illuminated with light from a MicroLED probe.
Results: In the caged-Glu-injected DG, the LFP changed in the 10-20 Hz frequency ranges after light illumination, whereas there was no change in the ACSF control condition.
Conclusion: The MicroLED probe is applicable for photopharmacological experiments to modulate LFP with caged-Glu in vivo.
(© 2024 The Author(s). Neuropsychopharmacology Reports published by John Wiley & Sons Australia, Ltd on behalf of The Japanese Society of Neuropsychopharmacology.)