Expression of choline acetyltransferase immunoreactivity in the rat red nucleus after postnatal enucleation

The presence of cholinergic neurones in the rat red nucleus (RN) is a controversial subject. We investigated this issue by immunocytochemistry in both adult, normal and neonatally enucleated rats. Choline acetyltransferase (ChAT)-immunoreactive neurones were found in the RN only of enucleated rats. An increase in cytochrome oxidase staining was also observed in the RN of enucleated rats. Our data support the concept that neurones in the rat RN are cholinergic and suggest that their activity could be modulated by the visual input.