POSTSYNAPTIC ELEMENT CONTRIBUTES TO THE DELAY IN SYNAPTOGENESIS IN SYNAPSIN I-DEFICIENT NEURONS

In a previous study, we reported a retardation in process outgrowth an d synapse formation in cultured hippocampal neurons from synapsin I-de ficient mice, were we investigated whether this delay in synaptogenesi s was attributable to pre- or postsynaptic elements. The experimental paradigm used in this study involved the establishment of heterochroni c cocultures of neurons from wildtype and synapsin I-deficient mice. N ewly cultured axons from wild-type and synapsin I-deficient neurons es tablished synapses with mature wild-type postsynaptic elements after 2 4 and 72 h, respectively. In contrast, synapsin I-deficient postsynapt ic elements were able to receive synapses only after 9 days in culture , representing a 5-day delay compared to controls. The results suggest a broad role for syplapsin I in the structural development of the syn apse, participating directly or indirectly in the maturation of both p resynaptic and postsynaptic sites.