The influence of mass of [11C]-laniquidar and [11C]-N-desmethyl-loperamide on P-glycoprotein blockage at the blood-brain barrier

These results demonstrate the bivalent character of laniquidar, acting as a substrate at low doses and as a blocking agent for P-glycoprotein transport in the brain at higher doses. In comparison, no difference was observed in [11C]-dLop uptake between carrier- and no-carrier-added formulations, which confirms that desmethyl-loperamide is a substrate of P-glycoprotein at the blood-brain barrier.