Fig. 3. D1CT transgene expression and D1 receptor and CNS neuroarchitecture of D1CT-7 mice. a, b, Bright-field view of ICC staining for the D1 receptor (dark staining with blue Nissl counterstain) in coronal brain sections, indicating no discernible changes in D1 receptor distribution, neuroanatomy, or density between control nontransgenic (a) and D1CT-7 (b) mice. c, d, Bright-field view of Nissl-stained sagittal brain sections, indicating no discernible changes in CNS morphology or neuron number between control nontransgenic (c) and D1CT-7 (d) mice. e, Bright-field view of ICC staining for the D1 receptor (dark staining) in a coronal section of the somatosensory and insular cortex [right (ventral to dorsal), insular, S2, S1] and the caudate-putamen (left), showing extensive D1 receptor expression in the caudate-putamen and less extensive but evident D1 receptor expression in the somatosensory and insular cortex, predominantly in layers II–III. f, Dark-field view of ISH staining for the presence of CT mRNA (light grains) performed on the same section shown in e, showing colocalization of CT mRNA with D1 receptor staining in the somatosensory and insular cortex layers II–III but not in the caudate-putamen. g, Dark-field view of ISH staining, detecting the presence of CT mRNA (light grains) in the piriform cortex layer II and the intercalated nucleus of the amygdala, regions that are also positive for D1 receptor mRNA and protein (data not shown). h, Higher magnification dark-field view of ISH staining of CT mRNA (light grains) in the intercalated nucleus of the amygdala in a coronal section parallel to that in g. Control nontransgenic littermates exhibit indistinguishable D1 receptor and Nissl staining in these regions and other CNS regions but no CT mRNA ISH staining (data not shown). This regionally restricted pattern of CT ISH staining to the areas shown was consistent between different D1CT-7 mice, reflecting the identical behavior of the animals of this line. For ISH, n = 3 per group; for Nissl, n = 4 per group; and for D1 receptor ICC,n = 2 per group. amy, Amygdala;c, cortex; CPu, caudate-putamen;en, endopiriform nucleus;ep/ic, entopeduncular nucleus/internal capsule; hpc, hippocampus; hyp, hypothalamus; icn, intercalated nucleus of the amygdala;pir, piriform cortex; I–VI, somatosensory cortical layers.