So there is a whole new class of therapy being developed. Instead of targeting receptors, they use gene therapy (using mRNA for example) to make the cell grow receptors that they can then target with what would otherwise be a totally benign compound. These are also called RASSLs - Receptor Activated Solely by Synthetic Ligands. So now it is theoretically possible to sneak mRNA into a shot and then later introduce a seemingly benign compound into the food supply.