
An imbalance in excitatory/inhibitory transmission, due to alterations in GABAergic signaling, has been suggested as an underlying cause of autism. These studies argue that the GABAergic system represents a viable therapeutic target for autism. Indeed, the GABA-B receptor agonist R-baclofen has been shown to ameliorate social deficits and repetitive behaviors in two mouse models of autism1. However, baclofen is known to exhibit relatively poor blood-brain-barrier permeability, arguing for the development of drug treatments more accessible to the central nervous system. Yet such drug discovery efforts are complicated by a lack of suitable radiotracers for imaging GABA-B receptors.