Histochemical identification of pallidal and striatal structures in the lizard Gekko gecko: evidence for compartmentalization.

The present study provides a description of the distribution patterns of enkephalin, substance P and dopamine immunoreactivity, and acetylcholinesterase activity in the striatum, nucleus accumbens, globus pallidus, and ventral pallidum of the Gekko gecko. The pallidal structures were identified on the basis of characteristic enkephalin and substance P immunoreactive plexus. The globus pallidus contains a very dense enkephalin immunoreactive woolly fiber plexus and a light and less extensive substance P immunoreactive plexus. The ventral pallidum is characterized by substance P and enkephalin immunoreactive woolly fiber plexus, which show a dense and moderate staining, respectively. The striatum and the nucleus accumbens were found to be inhomogeneous with respect to staining intensities for all four markers. Except for the enkephalin immunoreactivity distribution pattern in the striatum, the compartments that can be distinguished in material stained for these markers appear to coincide quite well.