Phylogenetic conservatism in the presence of a neurotensin-related hexapeptide in neurons of globus pallidus.

The vast majority of the pallidal neurons of the hamster, pigeon, caiman and turtle basal telencephalon were positively labeled by an antiserum against LANT-6, a neurotensin-like hexapeptide. In sharks also, LANT-6-positive neurons were observed in the apparent equivalent of the globus pallidus. These results, which imply the coexistence of a LANT-6-like peptide with gamma-aminobutyric acid (GABA) in pallidal neurons, suggest that a LANT-6-like peptide may be an important and evolutionarily conserved neurotransmitter/neuromodulator in pallidal neurons.