Distribution of NADPH-diaphorase positive somata in the brainstem of the monitor lizard Varanus exanthematicus.

The distribution and size of presumptive cholinergic somata in the brainstem of the Savanna monitor lizard Varanus exanthematicus were determined using the enzyme histochemical marker NADPH-diaphorase. Numerous neurons were labelled in the lizard brainstem with this technique. A three dimensional computer reconstruction of this population revealed that it shows marked similarity to the laterodorsal tegmental/pedunculopontine tegmental cholinergic cell column, an NADPH-diaphorase positive population in the mesopontine tegmentum of the mammalian brainstem.