Several A1R agonist have been reported to date; most of them have only minimal brain penetration. A nonselective agonist MRS5474 has shown antidepressant and anticonvulsant activities.82 While not optimum to fully map all the functions of the A1R in the brain, several 11 C and 18 F PET radioligands of the receptor have been evaluated for imaging of the A1R in the brain as described herein.
