Not All Receptor Cells Are Equal: Octopamine Exerts No Influence on Auditory Thresholds in the Noctuid Moth Catocala cerogama

MacDermid, V.; Fullard, James H.

doi:10.1007/s001140050540

Cited by 5 publications

(2 citation statements)

References 19 publications

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“…Efferent activity can provide protection from noise and facilitate the detection and discrimination of sound by modulating mechanical amplification by hair cells and transmitter release as well as auditory afferent action potential firing [1][2][3]. Insect auditory organs are thought to lack efferent control [4][5][6][7], but when we inspected mosquito ears, we obtained evidence for its existence. Antibodies against synaptic proteins recognized rows of bouton-like puncta running along the dendrites and axons of mosquito auditory sensory neurons.…”

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confidence: 99%

Auditory Efferent System Modulates Mosquito Hearing

et al. 2016

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The performance of vertebrate ears is controlled by auditory efferents that originate in the brain and innervate the ear, synapsing onto hair cell somata and auditory afferent fibers [1-3]. Efferent activity can provide protection from noise and facilitate the detection and discrimination of sound by modulating mechanical amplification by hair cells and transmitter release as well as auditory afferent action potential firing [1-3]. Insect auditory organs are thought to lack efferent control [4-7], but when we inspected mosquito ears, we obtained evidence for its existence. Antibodies against synaptic proteins recognized rows of bouton-like puncta running along the dendrites and axons of mosquito auditory sensory neurons. Electron microscopy identified synaptic and non-synaptic sites of vesicle release, and some of the innervating fibers co-labeled with somata in the CNS. Octopamine, GABA, and serotonin were identified as efferent neurotransmitters or neuromodulators that affect auditory frequency tuning, mechanical amplification, and sound-evoked potentials. Mosquito brains thus modulate mosquito ears, extending the use of auditory efferent systems from vertebrates to invertebrates and adding new levels of complexity to mosquito sound detection and communication.

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confidence: 99%

Auditory Efferent System Modulates Mosquito Hearing

et al. 2016

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“…However, two independent groups examined noctuid moth auditory organs and observed no efferent fibers in the area of receptor cell bodies suggesting octopamine modulation may not be involved at the peripheral sensory site [91,92]. MacDermid and Fullard [93] recorded tracings of auditory nerve after exposing it to sound pulses at different frequencies in presence and absence of octopamine in moth C. cerogama notodontid tympanum and reported no effect of octopamine on auditory thresholds [93]. In contrast, octopamine injections in the prothoracic ganglion result in an increase in the sensitivity of auditory system through the modulation of an auditory interneuron in the central nervous system of cricket Gryllus bimaculatus [94].…”

Section: Auditory Systemmentioning

confidence: 99%

Octopamine-Mediated Neuromodulation of Insect Senses

2007

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Octopamine functions as a neuromodulator, neurotransmitter, and neurohormone in insect nervous systems. Octopamine has a prominent role in influencing multiple physiological events: (a) as a neuromodulator, it regulates desensitization of sensory inputs, arousal, initiation, and maintenance of various rhythmic behaviors and complex behaviors such as learning and memory; (b) as a neurotransmitter, it regulates endocrine gland activity; and (c) as a neurohormone, it induces mobilization of lipids and carbohydrates. Octopamine exerts its effects by binding to specific proteins that belong to the superfamily of G protein-coupled receptors and share the structural motif of seven transmembrane domains. The activation of octopamine receptors is coupled with different second messenger pathways depending on species, tissue source, receptor type and cell line used for the expression of cloned receptor. The second messengers include adenosine 3',5'-cyclic monophosphate (cAMP), calcium, diacylglycerol (DAG), and inositol 1,4,5-trisphosphate (IP3). The cAMP activates protein kinase A, calcium and DAG activate protein kinase C, and IP3 mobilizes calcium from intracellular stores. Octopamine-mediated generation of these second messengers is associated with changes in cellular response affecting insect behaviors. The main objective of this review is to discuss significance of octopamine-mediated neuromodulation in insect sensory systems.

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