Consistently, in our study, we found that the receptors of important neural transmission systems, including dopamine receptors (DRD1, DRD2), GABA receptors (GABRA2, GABRA5) and 5-hydroxytryamine receptors (HTR1A, HTR2A), were all significantly down regulated in AD neurons (Fig. 7B). This evidence concerns the gene DRD1 and Alzheimer disease.