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Updated: Feb 13, 2026

Examining Monosynaptic Connections in Drosophila Using Tetrodotoxin Resistant Sodium Channels
Published on: February 14, 2018
Examining Monosynaptic Connections in Drosophila Using Tetrodotoxin Resistant Sodium Channels
Xiaonan Zhang1, Quentin Gaudry2
1Department of Biology, University of Maryland.
Abstract:
Here, a new technique termed Tetrotoxin (TTX) Engineered Resistance for Probing Synapses (TERPS) is applied to test for monosynaptic connections between target neurons. The method relies on co-expression of a transgenic activator with the tetrodotoxin-resistant sodium channel, NaChBac, in a specific presynaptic neuron. Connections with putative post-synaptic partners are determined by whole-cell recordings in the presence of TTX, which blocks electrical activity in neurons that do not express NaChBac. This approach can be modified to work with any activator or calcium imaging as a reporter of connections. TERPS adds to the growing set of tools available for determining connectivity within networks. However, TERPS is unique in that it also reliably reports bulk or volume transmission and spillover transmission.
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