The human hippocampal formation and parahippocampal gyrus: localization of substance P-like immunoreactivity in newborn and adult post-mortem tissue.

The localization of substance P-like immunoreactive nervous structures in the human post-mortem hippocampal formation and parahippocampal gyrus was studied by the indirect immunofluorescence technique of Coons and Kaplan (1950), J. exp. Med. 91, 1-9. Specimens were obtained from brains of both newborn and adult subjects. Substance P-positive perikarya were easily detectable in these regions, being particularly abundant in the stratum oriens of the hippocampus and in the hilus of the fascia dentata. The nerve fibres and terminals were also widely and unevenly distributed. Comparison of the newborn and adult tissue revealed differences in the distribution of substance P-like immunoreactivity in ontogenetic stages. Our results, together with data available in the literature, further suggest that substance P is differently distributed in the various cortical areas of the human brain, and that the distribution of substance P may vary among species.