Synaptic activity modulates presynaptic excitability.
Synaptic activity modulates synaptic efficacy and is important in learning and development. Here we show that development of excitability in presynaptic motor neurons required synaptic activation of postsynaptic muscle cells. Synaptic blockade broadened action potentials and decreased repetitive firing of presynaptic neurons. Consistent with these findings, synaptic blockade also decreased potassium-current density in the presynaptic cell. Application of neurotrophin-3, but not related neurotrophins, prevented these changes. Recordings from patches of somatic membrane indicated that modifications of presynaptic potassium and sodium currents occurred in a remote, nonsynaptic compartment. Thus, activity-dependent postsynaptic signals modulated presynaptic excitability, potentially regulating transmission at all synapses of the presynaptic cell.
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Department of Physiology and Biophysics, The University of Colorado Health Sciences Center, Denver, Colorado 80262, USA. teresa@etho.caltech.edu
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D000200:Action Potentials / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D002038:Bungarotoxins / Q000494:pharmacology; D002227:Carbazoles / Q000494:pharmacology; D018920:Coculture Techniques; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005246:Feedback; D026121:Indole Alkaloids; D007473:Ion Channels / Q000187:drug effects; D009046:Motor Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D009132:Muscles / Q000166:cytology; D009415:Nerve Net / Q000502:physiology; D020933:Neurotrophin 3 / Q000378:metabolism / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D017729:Presynaptic Terminals / Q000187:drug effects / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D013569:Synapses / Q000187:drug effects / Q000502:physiology*; D013570:Synaptic Membranes / Q000187:drug effects / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology*; D014981:Xenopus
D002038:Bungarotoxins; D002227:Carbazoles; D004791:Enzyme Inhibitors; D026121:Indole Alkaloids; D007473:Ion Channels; D020933:Neurotrophin 3; C049985:staurosporine aglycone; D012964:Sodium; D011188:Potassium