THE NEOSTRIATAL MOSAIC - BASIS FOR THE CHANGING DISTRIBUTION OF NEUROKININ-1 RECEPTOR IMMUNOREACTIVITY DURING DEVELOPMENT

The pattern of neurokinin-1 receptor-like immunoreactivity (NK-1Rir) w as mapped in perinatal and adult mouse striatum by using a new polyclo nal antiserum. NK-1Rir was detected in the differentiating regions of the ganglionic eminences on embryonic day 12.5 (E12.5). NK-1Rir struct ures were enriched in the striatal patch compartment between E16.5 and approximately postnatal day 3 (P3); distributed more uniformly, withi n portions of both the patch and matrix compartments on P7; and enrich ed in the matrix compartment in the adult. Analysis of the phenotype o f NK-1Rir cells on P2, P7, and in the adult suggested that cholinergic cells accounted for the majority of NK-1Rir cells early postnatally, with increasing contributions from somatostatinergic cells later postn atally. In the adult, approximately half of NK-1Rir cells were choline rgic and half were somatostatinergic. The transient enrichment of NK-1 R-bearing cells and processes in the patch compartment which contains cells that express substance P (SP), a putative ligand for the NK-1R, may be a consequence of compartment formation or may be functionally i mportant for compartment development. (C) 1996 Wiley-Liss, Inc.