Abstract
Immunohistochemical localization of retrogradely transported wheat germ agglutinin (WGA) is proposed as a sensitive histochemical technique to identify point to point connections within regions of the central nervous system. Injections of WGA into the median eminence of the hypothalamus and the caudate-putamen complex, respectively, were performed to illustrate that this material is rapidly transported over long distances and accumulates within the cytoplasm of neuronal perikarya and their processes. The applicability of this technique to identification of a second antigen within immunoreactive-WGA-labeled neurons is also demonstrated by sequential immunostaining of tyrosine hydroxylase within dopamine-containing cells of the mesencephalon, ipsilateral to an injection in the caudate-putamen complex. This technique is of use in characterizing bioaminergic neurons in the central nervous system and may also be of use in characterizing peptidergic neurons.