Paraformaldehyde-fixed 50 µm thick sagittal brain sections were incubated overnight at 4 °C in PBS with 5% normal goat serum and 0.5% Triton X-100 containing guinea pig monoclonal anti-Iba1 primary antibody (1:500, Synaptic Systems GmbH, Göttingen, Germany, 234308) and rat monoclonal anti-P2Y12R primary antibody (1:200, P2YM 17A12, this work). Sections were washed with PBS (3 ×) supplemented with 0.5% Triton X-100 and incubated for 2 h at rt with a suitable secondary antibody (anti-guinea pig and anti-rat antibody Alexa Fluor, ThermoFisher) and Dapi. Imaging was conducted on the THUNDER Imager Tissue (Leica Microsystems CMS GmbH, Wetzlar, Germany) with a ×20 objective for zoom-in and ×10 objective for overview picture in two sagittal sections. The images were processed using the LAS X Software (version 3.9.1.28433), and analysis was conducted with FiJi/ImageJ (version 1.54f) by quantifying Iba1 and P2Y12R signal over a predefined threshold.