Characterization of NPY mRNA-expressing cells in the human brain: co-localization with Y2 but not Y1 mRNA in the cerebral cortex, hippocampus, amygdala, and striatum

Neuropeptide Y (NPY) is one of the most abundant peptides in the central ne rvous system. Its effects on, for example, cognition, memory and motor func tions are thought to be mediated mainly via its interactions with the NPY Y 1 and Y2 receptor subtypes. We had previously described the neuroanatomical organization of the Y1 and Y2 mRNA expression in humans. However. in view of the lack of information regarding the overall detailed distribution of N PY mRNA expression in the human brain, a complete picture of the anatomical organization of the NPY-related genes was still missing. Thus, in the pres ent study, the regional distribution of NPY mRNA-expressing cells was analy zed in the post-mortem human brain. In addition, double labeling in situ hy bridization was performed to characterize the NPY neuronal populations in r elation to the Y1 and/or Y2 receptor mRNA localization in the human cerebra l cortex, striatum, and amygdala. NPY mRNA was found to be abundant in laye rs II and VI of the neocortex, polymorphic layer of the dentate gyrus, basa l ganglia, and amygdala. Double labeling in situ hybridization showed the c o-expression of NPY mRNA with the Y2, but not with the Y1, mRNA in the huma n cerebral cortex, hippocampus, amygdala, striatum, and nucleus accumbens, and the existence of co-expression of the Y1 and Y2 mRNAs in the cerebral c ortex and amygdala. Overall, these results suggest a role for the Y2, but n ot Y1, as an autoreceptor in the NPY neuronal populations of the human brai n. (C) 2000 Elsevier Science B.V. All rights reserved.