Fig. 7: LUXendin645 highlights GLP1R-expressing neurons in the brain.

a LUXendin645 labeling is detected in the the median eminence (ME), arcuate nucleus (ARC), area postrema (AP)/nucleus tractus solitaris (NTS), and choroid plexus (CP), in close association with GLP1-producing neurons, identified using GLU-YFP reporter animals (3V, third ventricle) (representative images from n = 4 animals) (scale bar = 106 µm). b Z-projection of an image stack (~30 µm) showing direct contacts between LUXendin645-labelled and GLP1-producing (GLU-YFP) neurons in the ARC (representative image from n = 4 animals) (scale bar = 20 µm). c, d LUXendin645 labeling co-localizes with GLP1R+ neurons in the AP/NTS c and ARC d, identified using GLP1RCre;LSL-GCaMP3 reporter animals (representative image from n = 4 animals) (scale bar = 61 µm). e Super-resolution imaging using Airyscan shows that LUXendin645 labeling is restricted to the membrane of the cell body and dendrites of GLP1R+ neurons (arrows show cell body and dendrite from left to right, respectively) (representative images from n = 4 animals) (scale bar = 9 µm). f GLP1R form nanodomains in ARC and AP neurons, as well as ependymal cells of the CP (confocal image is shown on the left for comparison) (representative images from n = 8 animals) (scale bar = 9 µm). g Mapping of LUXendin645 distribution in cleared brains shows labelling of the ARC, AP/NTS, CP, lateral ventricles (LV), fourth ventricle (4V), subfornical organ (SFO), and organum vasculosum of the lamina terminalis (OVLT) (representative images from n = 4 animals) (scale bar = 1 mm). Note that, due to suspension of the brain, the coronal section is slightly offset in the dorsal–ventral plane; hence, the SFO appears above the ARC. In all cases, LUXendin645 was injected subcutaneously at 100 pmol/g.