Co-localisation of NADPH diaphorase activity and GABA immunoreactivity in local circuit neurones in the medial prefrontal cortex (mPFC) of the rat.

This study provides evidence that neurones in the medial prefrontal cortex of the rat (mPFC areas 24b, 25, and 32) containing strong NADPH diaphorase reactivity also contain GABA immunoreactivity. Also demonstrated is the co-localisation of NADPH diaphorase activity with immunoreactivity for the neuronal isoform of nitric oxide synthase (nNOS) in mPFC neurones. Qualitative and quantitative analyses in the light and electron microscopes indicate that strongly NADPH diaphorase reactive cells are a subpopulation of GABAergic local circuit neurones and constitute a very small proportion (0.6-1.1%) of neurones in rat mPFC. These results suggest that NADPH diaphorase reactive cells in rat mPFC can influence neural activity via GABA-mediated and NO-mediated mechanisms.