General Principles of Receptor Binding

The increasing availability over the past 20 yr of biologically active radiolabeled compounds of high-specific activity has enabled investigators to label and quantitatively assay the receptor (recognition) sites that are thought to mediate the agonistic or antagonistic effects of putative neurotransmitters and many psychotropic drugs in the brain. Such direct studies of ligand-receptor interaction have resulted in a significant increase in our understanding of the processes at the molecular level involved in the action of various neurotransmitters, peptides, and drugs at their respective receptive sites in target tissues.