Thalamic nuclei that project to reptilian telencephalon lack GABA and GAD immunoreactive neurons and puncta.

Brains of reptiles, Caiman crocodilus, were processed by standard immunocytochemical methodology using a polyclonal antibody to gamma-aminobutyric acid (GABA) raised in rabbit and a polyclonal antibody to glutamic acid decarboxylase (GAD) raised in sheep. No GABA(+) or GAD(+) cells or puncta were observed over any thalamic nucleus known to project to the telencephalon in Caiman. These findings suggest that all thalamic nuclei that project to the telencephalon in Caiman lack intrinsic cells and presumably direct inhibitory input mediated by GABA.