Patterns of calretinin, calbindin, and tyrosine-hydroxylase expression areconsistent with the prosomeric map of the frog diencephalon

This paper re-examines a previously published segmental map of the frog die ncephalon (Puelles et aI. [1996] Brain Behav.Evol. 47:279-310) by means of immunocytochemical mapping of calretinin, calbindin, and tyrosine hydroxyla se. The distribution of neuronal populations, axon tracts, and neuropils im munoreactive for these markers was studied in adult specimens of Rana perez i and Xenopus laevis sectioned sagittally or horizontally. Emphasis was pla ced on study of the relationship of observed chemoarchitectural boundaries with the postulated overall prosomeric organization and the schema of nucle ar subdivisions we reported previously, based on acetylcholinesterase histo chemistry and Nissl pattern in Rana. The data reveal a large-scale correspo ndence with the segmental map in both species, although some differences we re noted between Rana and Xenopus. Notably, retinorecipient neuropils were generally immunoreactive for calretinin only in Rana. Importantly, calretin in immunostaining underlines particularly well the transverse prosomeric bo undaries of the dorsal thalamus. A number of nuclear subdivisions noted bef ore with AChE were corroborated, and some novel subdivisions became apparen t particularly in the anterior nucleus of the dorsal thalamus and in the ha benular complex. The mapping of tyrosine hydroxylase clarified the segmenta l distribution of the catecholaminergic cell groups in the frog forebrain, which is comparable to that observed in other vertebrates. J. Comp. Neurol. 419:96-121, 2000. (C) 2000 Wiley-Liss, Inc