Topographic distribution and quantitative analysis of retrograde-labelled cells in the substantia nigra following administration of fluoro gold in the caudate putamen nucleus

Abstract

The organization of the efferent projections of the substantia nigra following the irijection of 0.4 pl of 2% Fluoro Gold into the caudate-putamen nucleus of rats of both sexes was studied. After a survival period of 77 h. the greatest number of labelled cells was visuali~ed in ihe substantia nigra, with lower numbers in adjacent structures (ventral tegrnental area. zona incei-ta and ~rredial leinniscus). The cclls featured an intensely fluorescent goldcoloured soma and were varied in .shape (round or n\:al); short sinuous projectioris arose out of thein. corresponding to the dendrites and axons of the neurons. ln the statistical study. no significant differences were observed between r-iiales and females. A sirrrilar pattern of distribution was found rangirig Sr0111 ihe rostral to the caudal regions of the substantia niyra. occupying the whole of the extent of the suhstantia nigra; this distribution was most predominant in the rostro-caudal transition of the pars compacta of the substantia nigra.