Immunohistochemical and RT PCR studies confirm the presence of TrkA in mature and immature cortical cultures alongside α7-containing nAChRs and m2 mAChRs. Fluorescence image of TrkA-immunoreactivity (green; see arrows) co-stained with neuron-specific ß-tubulin (red) and DNA nuclear stain Hoechst 33342 (blue) in mature (A) and immature (B) cultures. (C) Confocal image of TrKA localised to both the cytosol (upper arrow) and on the surface of a different cell located at a lower level in the Z-stack (lower arrow) in a mature culture. (D&E) Co-localisation of m2 mAChR (red) and m1 mAChRs (green) showing relatively higher levels of m1 mAChR expression along the apical dendrite (arrows) and general expression throughout the neuropil in a mature culture. (F i-iv) Confocal images of α7-containing nAChR positive cells (green) demonstrating the high level of α7-containing nAChR expression both on the soma and apical dendrite but limited punctate expression throughout the dendritic tree (Fiv arrows) and labelled with beta tubulin in (ii) in a mature culture. (G) Electrophoresis of RT PCR products shows corresponding bands at 143 (TrkA) and 147 (ChAT) and 244 (ß-actin) in both mature cultures and rat medial septum tissue positive control.