Quantitation of synaptic vesicle antigen in rabbit superior colliculus during normal development and after neonatal...

Radioimmunoassay of a synaptic vesicle-associated antigen (SV Ag) using monoclonal antibodies was used to study synapse formation in the rabbit superior colliculus (SC). Normal postnatal development was compared with development following unilateral neonatal visual cortex lesion. Neonatal lesion of the visual cortex prevents the cortical innervation of the SC, which normally accounts for 35% of the total SV Ag levels in the rabbit SC. Following such lesions, a small but significant increase in SV Ag levels over that in normally innervated SC was observed. These observations suggest that competition between retinotectal and corticotectal inputs may be required for normal development of synaptic connections in the SC.