Insights from honeybee (Apis mellifera) and fly (Drosophila melanogaster) nicotinic acetylcholine receptors: From genes to behavioral functions
Neuroscience & Biobehavioral Reviews. 2012-07-01; 36(6): 1553-1564
DOI: 10.1016/j.neubiorev.2012.04.003
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Nicotinic acetylcholine receptors (nAChRs) are widely expressed throughout the
central nervous system of insects where they supply fast synaptic excitatory
transmission and represent a major target for several insecticides. The unbalance
is striking between the abundant literature on nAChR sensitivity to insecticides
and the rarity of information regarding their molecular properties and cognitive
functions. The recent advent of genome sequencing disclosed that nAChR gene
families of insects are rather small-sized compared to vertebrates. Behavioral
experiments performed in the honeybee demonstrated that a subpopulation of nAChRs
sensitive to the venom α-bungarotoxin and permeant to calcium is necessary for
the formation of long-term memory. Concomitant data in Drosophila reported that
repetitive exposure to nicotine results in a calcium-dependent plasticity of the
nAChR-mediated response involving cAMP signaling cascades and indicated that
ACh-induced Ca++ currents are modulated by monoamines involved in aversive and
appetitive learning. As in vertebrates, in which glutamate and NMDA-type
glutamate receptors are involved in experience-associated synaptic plasticity and
memory formation, insects could display a comparable system based on ACh and
α-Bgt-sensitive nAChRs.