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The chemical component of the mixed GF-TTMn synapse in Drosophila melanogaster uses acetylcholine as its neurotransmitter


  • Marcus J. Allen,

    1. Department of Biosciences, University of Kent, Canterbury, Kent, CT2 7NJ, UK
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  • R. K. Murphey

    1. Department of Biology, Morrill Science Center, University of Massachusetts, Amherst, Massachusetts 01003, USA
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    • *

      Present address: Department of Biological Sciences, Florida Atlantic University, 777 Glades Road, Boca Raton, FL 33431, USA.

  • Re-use of this article is permitted in accordance with the Creative Commons Deed, Attribution 2.5, which does not permit commercial exploitation.

Dr Marcus J. Allen, as above.
E-mail: M.J.Allen@kent.ac.uk


The largest central synapse in adult Drosophila is a mixed electro-chemical synapse whose gap junctions require the product of the shaking-B (shak-B) gene. Shak-B2 mutant flies lack gap junctions at this synapse, which is between the giant fibre (GF) and the tergotrochanteral motor neuron (TTMn), but it still exhibits a long latency response upon GF stimulation. We have targeted the expression of the light chain of tetanus toxin to the GF, to block chemical transmission, in shak-B2 flies. The long latency response in the tergotrochanteral muscle (TTM) was abolished indicating that the chemical component of the synapse mediates this response. Attenuation of GAL4-mediated labelling by a cha-GAL80 transgene, reveals the GF to be cholinergic. We have used a temperature-sensitive allele of the choline acetyltransferase gene (chats2) to block cholinergic synapses in adult flies and this also abolished the long latency response in shak-B2 flies. Taken together the data provide evidence that both components of this mixed synapse are functional and that the chemical neurotransmitter between the GF and the TTMn is acetylcholine. Our findings show that the two components of this synapse can be separated to allow further studies into the mechanisms by which mixed synapses are built and function.