Simultaneous Pre- and Post-synaptic Electrophysiological Recording from Xenopus Nerve-muscle Co-cultures

Much information about the coupling of presynaptic ionic currents with the release of neurotransmitter has been obtained from invertebrate preparations, most notably the squid giant synapse(1). However, except for the preparation described here, few vertebrate preparations exist in which it is possible to make simultaneous measurements of neurotransmitter release and presynaptic ionic currents. Embryonic Xenopus motoneurons and muscle cells can be grown together in simple culture medium at room temperature; they will form functional synapses within twelve to twenty-four hours, and can be used to study nerve and muscle cell development and synaptic interactions for several days (until overgrowth occurs). Some advantages of these co-cultures over other vertebrate preparations include the simplicity of preparation, the ability to maintain the cultures and work at room temperature, and the ready accessibility of the synapses formed(2-4). The preparation has been used widely to study the biophysical properties of presynaptic ion channels and the regulation of transmitter release(5-8). In addition, the preparation has lent itself to other uses including the study of neurite outgrowth and synaptogenesis(9-12), molecular mechanisms of neurotransmitter release(13-15), the role of diffusible messengers in neuromodulation(16,17), and in vitro synaptic plasticity(18-19).