Calcium binding protein immunoreactivity in a reptilian thalamic reticular nucleus

Immunoreactivity to antisera directed against a variety of calcium binding proteins was investigated in the thalamic reticular nucleus of one species of reptiles, Caiman crocodilus. Cells and fibers were immunoreactive for parvalbumin whereas fibers but not neurons were immunoreactive for calbindin and calcitonin gene related peptide. These data support the observations that Caiman thalamic reticular nucleus contains at least two neuronal populations. One group, whose cells are immunoreactive for parvalbumin, forms at least part of the projection to the dorsal thalamus. The other group, which contains qualitatively different and sparser number of neurons, is immunoreactive for glutamic acid decarboxylase.