Neuroendocrine modulation of olfactory sensory neuron signal reception via axo-dendritic synapses in the antennae of the mosquito, Aedes aegypti

An ultrastructural study of the antennae of the yellow fever mosquito, Aedes aegypti, revealed that as in the salt marsh mosquito, Culex salinarius, the first flagellar segment of both sexes of A. aegypti contain neuroendocrine cells. These cells not only extend an axon via the antennal nerve to the antennal lobe of the deutocerebrum, but project collaterals to the periphery of the antennae, where they modulate the antennal sensory neurons by forming synapses with the dendrites of these afferent neurons. To our knowledge, this is the first report in any animal of neurites of neuroendocrine cells forming axo-dendritic synapses with sensory neurons.