Biochemical maturation of the non-innervated chick optic lobe.

The development of the chick optic lobe was impaired following removal of the optic cup of the early embryo. Tectal cell number is reduced but cell size may be relatively normal. Ther was evidence of neuronal cell death and several neuron-associated proteins and enzymes (nerve-specific protein and acetylcholinesterase) showed selectively impaired maturation. However, other nerve-specific enzymes (choline acetyltransferase, tyrosine hydroxylase), develop normally on a per cell basis. The noninnervated optic lobe had a normal blood-brain barrier but a depressed ability to accumulate amino acids from plasma. Levels of 3':5'-cyclic GMP were also reduced in the nonafferented lobe.