Regulation of alpha2A‐AR trafficking by clonidine and guanfacine in native neurons

Abstract

Despite intensive studies on alpha2-adrenergic receptor (AR) trafficking in heterologous systems, the properties of different agonists in inducing alpha2-AR internalization and subsequent sorting in native cells remain elusive. We have developed a mouse line in which N-terminal HA-tagged alpha2A-AR expression is driven by the endogenous mouse alpha2A-AR locus. This HA-alpha2A-AR knock-in mouse line allows us to study alpha2A-AR trafficking studies in native cells. Two alpha2-AR agonists, clonidine and guanfacine have been widely used to treat attention deficit and hyperactivity disorder clinically, however, these two drugs can cause different degree of sedative response on patients. In mice, we found that the EC50 of clonidine to induce sedation is 20 folds higher than that of guanfacine. To understand the molecular and cellular mechanisms underlying selective regulation of alpha2A-AR-mediated physiological/pharmacological responses by these two agonists, we studied alpha2A-AR trafficking and ERK signaling in native neocortical neurons induced by these agonists, exploiting the HA-alpha2A-AR knock-in mice. We found that alpha2A-AR internalization induced by clonidine occurred more rapidly than that induced by guanfacine. Our studies provide the first documentation of endogenously expressed alpha2A-AR trafficking in native neocortical neurons. This research is supported by American Heart Association Scientist Development Grant to QW.