Fig. 1: Platform for AVATar construction.
From: Target-responsive vasoactive probes for ultrasensitive molecular imaging
a PACAP (blue) functions as a vasoprobe by binding to receptors on vascular smooth muscle cells and activating a cAMP-dependent signaling cascade, causing blood vessel dilation and a hemodynamic imaging signal. b AVATar architecture: a tethered version of the target molecule is attached to PACAP peptide (blue); binding of a blocking domain (green) to the tethered target prevents receptor activation. Elevated free target molecule concentrations free active PACAP from the blocking interaction. c Map of mean MRI signal change following intracranial delivery of 1 µM PACAP (blue arrowhead) compared to aCSF vehicle (white arrowhead), overlaid on an anatomical scan. Scale bar = 2 mm. d Mean MRI time courses during delivery of 1 µM PACAP (blue) or aCSF vehicle (black). Shading represents SEM (n = 4). e Average MRI signal change 30–40 min after PACAP or vehicle injection (horizontal lines = mean values, n = 4).
