The distribution of tachykinin NK1 and NK3 receptors in the prefrontal (Brodmann area 9) and visual cortex (Brodmann area 17) of formalin-fixed postmortem human brain tissue was studied by immunohistochemistry. NK1-like immunoreactivity (NK1-LI) was observed as a thin band at the cortical surface and dots of NK1-LI localised on small non-pyramidal cells and in the neuropil (layers I-III). NK3-LI was found in beaded fibres and cells with astrocyte-like morphology in the superficial cortical layers and white matter. Dots of NK3-LI were prominent in the neuropil and on pyramidal (layers III/V) and non-pyramidal (layers V/VI) cells. The NK3-LI was more abundant and widespread than the NK1-LI. This is the first report of the distribution of the NK1 receptor in the prefrontal and visual cortex of the human brain by immunohistochemistry. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.