Abstract Aims The endocannabinoid system with its type 1 cannabinoid receptor (CB1R) expressed in postmitotic neuroblasts is a critical chemotropic guidance module with its actions cascading across neurogenic commitment, neuronal polarisation and synaptogenesis in vertebrates. Here, we present the systematic analysis of regional CB1R expression in the developing human brain from gestational week 14 until birth. In parallel, we diagrammed differences in CB1R development in Down syndrome foetuses and identified altered CB1R signalling. Methods Foetal brains with normal development or with Down's syndrome were analysed using standard immunohistochemistry, digitalised light microscopy and image analysis (NanoZoomer). CB1R function was investigated by in vitro neuropharmacology from...
