Rapid loss of nicotine-cholinergic receptor binding activity in the deafferented avian optic lobe

The levels of alpha-bungarotoxin (alpha-BuTX) sensitive receptor sites were investigated in the optic lobe after optic deafferentation in the neonatal and adult chicken. Within two days a 30% loss of alpha-BuTX binding sites per optic lobe is observed in the neonatal chick after enucleation. The results are similar with the adult chicken in experiments where the receptor binding activity is measured in the optic lobe and in the optic tectum after enucleation. The possibility that acetylcholine is a neurotransmitter in the vertebrate retinotectal pathway is discussed.