Researchers believe they have found a way to change the action of 60 percent of currently available medications, in some cases making them many times more effective, according to an article published in the April 21 edition of the journal Science. The discovery has the potential to improve treatments for diseases including heart disease, cancer, diabetes, depression and arthritis. The study describes a new way to manipulate perhaps the most important signaling mechanism in human cells: G-protein coupled receptors (GPCRs).