KCNJ3 and Alzheimer disease: The strikingly parallel reduction in the density of GIRK1 and GIRK2, together with the reduction of GIRK1 labelling observed in the hippocampus of GIRK2 KO mice [16], is compatible with the idea that a significant fraction of hippocampal GIRK channels, both in AD and healthy animals, are heteromultimers composed of GIRK1 and GIRK2.