2 MODES OF ACTIVITY-DEPENDENT SYNAPTOGENESIS OF CEREBRAL NEURONS IN-VITRO

EFFECTs of transduction activity and transmission activity on synaptog enesis of chick cerebral neurones in dissociated cell culture were stu died electrophysiologically using two blockers for these activities, t etrodotoxin (TTX) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX), res pectively. CNQX inhibited the increase of evoked EPSCs more effectivel y than TTX, whereas both blockers similarly reduced the increase of mi niature EPSCs (Minis). These data indicated that not only transduction -dependent transmission activity but also transduction-independent spo ntaneous activity regulate the synaptic efficiency. These two activiti es are suggested to change the quantal amplitude and the number of syn aptic sites, respectively.