Brussels - Adrenaline, the hormone that prepares our body to fight or flight, acts on a hyperdynamic receptor. This molecule switches so fast between several positions, that it was impossible to image it. Until now. Scientists, including Jan Steyaert of VIB and the Vrije Universiteit Brussel in Belgium, and colleagues from Stanford University in the US, have "frozen the molecule in action" using Xaperones™, tiny, stable antibodies developed by the Brussels scientists. The Xaperones™ bind like a key to a lock, holding the adrenaline receptor in one position -- the on position.