Response of neuropeptides and neurotransmitter binding sites in the retina and brain of the developing chick to reduced visual input

Abstract

The effect of 17 days of monocular suture of eyelids of day-old chicks upon levels of neuropeptides and high affinity binding sites was studied. A significant reduction of met-enkephalin, but not of substance P or neurotensin, was observed in the retina of the eye receiving dim and unpatterned light. Retinal muscarinic, dopaminergic, opiate, and benzodiazepine receptors appeared unaltered by the experimental procedure. Levels of neuropeptides were not significantly changed in optic lobes contralateral to and innervated by the sutured eyes relative to the optic lobes receiving afferentation from the open eyes. Seventeen days after unilateral enucleation of new-hatched chicks, the neuropeptide content of the smaller denervated optic lobes did not differ from that of the lobes receiving an intact neuronal input.