title: Synapsin IIa accelerates functional development of neuromuscular synapses.
abstract: We have investigated the possible involvement of the synaptic vesicle protein synapsin IIa in synapse development. Synapsin IIa was introduced into Xenopus embryonic spinal neurons by early blastomere injection, and nerve-muscle cultures were prepared. Synaptic currents were measured by comparing synapses in which the presynaptic neuron either contained [syn IIa (+)] or lacked (control) exogenous synapsin IIa. Syn IIa (+) synapses had a 3.6-fold increase in the frequency and a 2.1-fold increase in the amplitude of spontaneous synaptic currents, compared to controls, after 2 days in culture. Synapsin IIa also increased the amplitude of evoked synaptic currents by 2.3-fold in 2-day cultures. The evoked synaptic current amplitudes of syn IIa (+) synapses had a lower coefficient of variation indicating a more stable evoked response. These enhanced synaptic activities were independent of the presence or absence of the protein in the postsynaptic muscle cell. The findings indicate a role for synapsin IIa in synapse maturation.
authors.affiliation: Laboratory of Molecular and Cellular Neuroscience, Rockefeller University, New York, NY 10021.
authors.forename: E
authors.initials: E
authors.lastname: Schaeffer
authors.forename: J
authors.initials: J
authors.lastname: Alder
authors.forename: P
authors.initials: P
authors.lastname: Greengard
authors.forename: M M
authors.initials: MM
authors.lastname: Poo
mesh_terms: D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D002454:Cell Differentiation; D002478:Cells, Cultured; D004594:Electrophysiology; D066298:In Vitro Techniques; D009469:Neuromuscular Junction / Q000166:cytology / Q000502:physiology*; D011994:Recombinant Proteins; D013569:Synapses / Q000502:physiology*; D016704:Synapsins / Q000494:pharmacology / Q000502:physiology*; D009435:Synaptic Transmission; D014982:Xenopus laevis / Q000196:embryology
chemical_list: D011994:Recombinant Proteins; D016704:Synapsins; D000109:Acetylcholine