Enkephalin and Receptor (IMAGE) Ruhr-University Bochum Caption The enkephalin receptor (gray) threads through the cell membrane. The structure of the free enkephalin in the complex with the rhodium atom (orange) is highlighted in green. Credit Florian Wieberneit (Biomolecular NMR) Usage Restrictions None License Licensed 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.