Three-Photon Infrared Stimulation of Endogenous Neuroreceptors in Vivo |
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Authors: | Rosalba Sortino Marina Cunquero Gustavo Castro-Olvera Ricard Gelabert Miquel Moreno Fabio Riefolo Carlo Matera Noèlia Fernàndez-Castillo Luca Agnetta Michael Decker José M. Lluch Jordi Hernando Pablo Loza-Alvarez Pau Gorostiza |
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Affiliation: | 1. Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute for Science and Technology, 08028 Barcelona, Spain;2. ICFO—Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860 Castelldefels (Barcelona), Spain;3. Departament de Química, Universitat Autònoma de Barcelona (UAB), 08193 Bellaterra, Spain;4. CIBER-BBN, ISCIII, 28029 Madrid, Spain;5. Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy and Food Chemistry, Ludwig Maximilian University of Würzburg, 97074 Würzburg, Germany |
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Abstract: | To interrogate neural circuits and crack their codes, in vivo brain activity imaging must be combined with spatiotemporally precise stimulation in three dimensions using genetic or pharmacological specificity. This challenge requires deep penetration and focusing as provided by infrared light and multiphoton excitation, and has promoted two-photon photopharmacology and optogenetics. However, three-photon brain stimulation in vivo remains to be demonstrated. We report the regulation of neuronal activity in zebrafish larvae by three-photon excitation of a photoswitchable muscarinic agonist at 50 pM, a billion-fold lower concentration than used for uncaging, and with mid-infrared light of 1560 nm, the longest reported photoswitch wavelength. Robust, physiologically relevant photoresponses allow modulating brain activity in wild-type animals with spatiotemporal and pharmacological precision. Computational calculations predict that azobenzene-based ligands have high three-photon absorption cross-section and can be used directly with pulsed infrared light. The expansion of three-photon pharmacology will deeply impact basic neurobiology and neuromodulation phototherapies. |
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Keywords: | Azobenzene Multiphoton Excitation Muscarinic Neuromodulation Photopharmacology Two-Photon Lithography and Polymerization |
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