Cryogenic electron microscopy structure (IMAGE) Monash University Caption A cartoon of the cryogenic electron microscopy structure of the human adenosine A1 receptor (coloured blue) bound to its signalling protein (coloured pink, green, and purple), adenosine (purple spheres) and a proof-of-concept non-opioid analgesic (coloured as orange spheres). Credit (C) Monash University Usage Restrictions This image can only be used in conjunction with this paper. License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.