PRENATAL COCAINE INCREASES STRIATAL SEROTONIN INNERVATION WITHOUT ALTERING THE PATCH MATRIX ORGANIZATION OF INTRINSIC CELL-TYPES

The effect of prenatal cocaine on the anatomical development of the st riatum was examined. The distribution and density of dopaminergic inne rvation of the striatum of animals exposed to cocaine during the secon d and third week of gestation was not noticeably different from prenat ally saline-injected or untreated controls at any age. The patch/matri x organization of the striatum also appeared unaltered: neurons exhibi ting dense substance P staining were localized to patches that overlap ped dopamine terminal patches early in development, and enkephalin- an d calbindin-immunoreactive neurons were found segregated to the matrix . Histochemical staining for acetylcholinesterase and NADPH diaphorase also revealed no differences between prenatally cocaine-treated and c ontrol brains. Whereas prenatal cocaine treatment failed to modify the basic compartmental organization of the striatum, it did lead to a hy perinnervation of serotonin-immunoreactive fibers which developed slow ly after birth. Thus prenatal exposure to cocaine is capable of alteri ng the ingrowth of serotonergic projections to the striatum while prod ucing no change in the organization of neurons intrinsic to the striat um.