Nicotine and the Cation-π Interaction (image) California Institute of Technology Share Print E-Mail Caption This molecular model shows nicotine (in center) binding to a brain receptor via a cation-π interaction. Credit Caltech/Dennis Dougherty Usage Restrictions With credit as given above. Share Print E-Mail 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.