The Yoburn lab focuses on the mechanism of action of opioid drugs. Our work involves studies that target understanding opioid drug action; beginning with the interaction of opioids with specific opioid receptors and culminating with functional drug effects. As with many other neurotransmitter systems, opioid receptors and signaling pathways have dynamic properties and can be actively regulated by exposure to agonists and antagonists. The potency of opioids can be affected by a number of elements in the cascade leading from the receptor to effect. Examining the the role of drug efficacy on changes in agonist potency and the regulation of opioid receptor density and function are recurring themes in our efforts. Recently, we have been particularly interested in the contribution of dosing schedules and drug efficacy to regulation of receptors, intracellular messengers coupled to receptors, and, in particular, tolerance and dependence.  Throughout our studies, a systems molecular pharmacological approach is employed.