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

Neuropsychopharmacol Rep. 2024 Sep;44(3):658-662. doi: 10.1002/npr2.12472. Epub 2024 Aug 9.

Abstract

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.

Keywords: caged‐glutamate; hippocampus; local field potential (LFP); microscale light‐emitting diode (MicroLED); photopharmacology.

MeSH terms

  • Animals
  • Dentate Gyrus / drug effects
  • Dentate Gyrus / physiology
  • Glutamic Acid* / pharmacology
  • Hippocampus* / drug effects
  • Hippocampus* / physiology
  • Light
  • Male
  • Mice
  • Mice, Inbred C57BL

Substances

  • Glutamic Acid