Imaging Striatal Dopamine Release Using a Non-Genetically Encoded Near-Infrared Fluorescent Catecholamine Nanosensor

Abraham G. Beyene; Kristen Delevich; Jackson Travis Del Bonis-O’Donnell; David J. Piekarski; Wan Chen Lin; A. Wren Thomas; Sarah J. Yang; Polina Kosillo; Darwin Yang; Linda Wilbrecht; Markita P. Landry

Mice were C57 Bl/6 strain, 60 days old, and both male and female mice were used. Mice were group housed after weaning at P21 and kept with nesting material on a 12:12 light cycle. All animal procedures were approved by the UC Berkeley Animal Care and Use Committee (ACUC). Acute brain slices were prepared using established protocols. 28 Briefly, mice were deeply anesthetized via intraperitoneal injection of ketamine/xylazine cocktail and transcardial perfusion was performed using ice-cold cutting buffer (119 mM NaCl, 26.2 mM NaHCO3, 2.5 mM KCl, 1mM NaH2PO4, 3.5 mM MgCl2, 10 mM Glucose, 0 mM CaCl2), after which the brain was rapidly extracted. The cerebellum and other connective tissues were trimmed using a razor blade and the brain was mounted onto the cutting stage of a vibratome (Leica VT 1200S). Coronal slices (300 µm in thickness) including the dorsal striatum were prepared. Slices were incubated at 37°C for 60 minutes in oxygen saturated ACSF (119 mM NaCl, 26.2 mM NaHCO3, 2.5 mM KCl, 1mM NaH2PO4, 1.3 mM MgCl2, 10 mM Glucose, 2 mM CaCl2) before use. Slices were then transferred to room temperature for 30 minutes before starting imaging experiments and were maintained at room temperature for the remainder of experimentation.