Weakly Electric Fish: Behavior, Neurobiology, and Neuroendocrinology

Dunlap, Kent D.

doi:10.1016/b978-0-12-803592-4.00019-5

Cited by 10 publications

(8 citation statements)

References 209 publications

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“…Nocturnally active mormyrid electric fish produce brief, weak voltage electric fields, called electric organ discharges (EODs) to form electrosensory images of their environments and to communicate during courtship (6). Though EOD waveforms are known to be influenced by both natural and sexual selection pressures (7)(8)(9), the molecular targets and biophysical mechanisms for selection remain elusive.…”

Section: Introductionmentioning

confidence: 99%

Electrostatic Tuning of a Potassium Channel in Electric Fish

Swapna

Ghezzi

Markham

et al. 2017

Preprint

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Abstract:Molecular and biophysical variation contributes to the evolution of adaptive phenotypes, particularly behavior, though it is often difficult to understand precisely how. The adaptively significant electric organ discharge behavior of weakly electric fish is the direct result of biophysical membrane properties set by ion channels. Here we describe a voltage-gated potassium channel gene in African mormyrid electric fishes, that is under positive selection and highly expressed in the electric organ. The channel produced by this gene shortens electric organ action potentials by activating quickly and at hyperpolarized membrane potentials. Surprisingly, the source of these unique properties is a derived patch of negatively charged amino acids in an extracellular loop near the voltage sensor. Further, we demonstrate that this portion of the channel functions differently in vertebrates than the generally accepted model based on the . CC-BY-NC-ND 4.0 International license It is made available under a (which was not peer-reviewed) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity.The copyright holder for this preprint . http://dx.doi.org/10.1101/206243 doi: bioRxiv preprint first posted online Oct. 19, 2017; 2 shaker channel, and suggest a role for this loop in the evolutionary tuning of voltage-dependent channels.

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Section: Introductionmentioning

confidence: 99%

Electrostatic Tuning of a Potassium Channel in Electric Fish

Swapna

Ghezzi

Markham

et al. 2017

Preprint

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“…The electric organs of these fish continuously produce high-frequency electric organ discharges (EODs) that are used to identify nearby objects and to communicate with conspecifics. Electric organ discharge frequency (EODf) varies across species, and in many species is sexually dimorphic (reviewed in Smith 2013; Dunlap et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Genes linked to species diversity in a sexually dimorphic communication signal in electric fish

et al. 2017

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Sexually dimorphic behaviors are often regulated by androgens and estrogens. Steroid receptors and metabolism are control points for evolutionary changes in sexual dimorphism. Electric communication signals of South American knifefishes are a model for understanding the evolution and physiology of sexually dimorphic behavior. These signals are regulated by gonadal steroids and controlled by a simple neural circuit. Sexual dimorphism of the signals varies across species. We used transcriptomics to examine mechanisms for sex differences in electric organ discharges (EODs) of two closely related species, Apteronotus leptorhynchus and Apteronotus albifrons, with reversed sexual dimorphism in their EODs. The pacemaker nucleus (Pn), which controls EOD frequency (EODf), expressed transcripts for steroid receptors and metabolizing enzymes, including androgen receptors, estrogen receptors, aromatase, and 5α-reductase. The Pn expressed mRNA for ion channels likely to regulate the high-frequency activity of Pn neurons and for neuromodulator and neurotransmitter receptors that may regulate EOD modulations used in aggression and courtship. Expression of several ion channel genes, including those for Kir3.1 inward-rectifying potassium channels and sodium channel β1 subunits, was sex-biased or correlated with EODf in ways consistent with EODf sex differences. Our findings provide a basis for future studies to characterize neurogenomic mechanisms by which sex differences evolve.

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“…Here, we revisit this comparison and review what has been learned in the intervening 16 years. We only briefly summarize the basics of each system since many comprehensive reviews have been published ( Dunlap et al, 2017 ; Feng and Bass, 2017 ; Bass et al, 2019 ; Metzen, 2019 ). Instead, we focus on several key neural and endocrine processes that have been researched recently in both teleost systems and make direct comparisons to highlight how these analogous communication systems have evolved similar and different mechanisms.…”

Section: Introductionmentioning

confidence: 99%

Vocal and Electric Fish: Revisiting a Comparison of Two Teleost Models in the Neuroethology of Social Behavior

Dunlap

Koukos

Chagnaud

et al. 2021

Front. Neural Circuits

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The communication behaviors of vocal fish and electric fish are among the vertebrate social behaviors best understood at the level of neural circuits. Both forms of signaling rely on midbrain inputs to hindbrain pattern generators that activate peripheral effectors (sonic muscles and electrocytes) to produce pulsatile signals that are modulated by frequency/repetition rate, amplitude and call duration. To generate signals that vary by sex, male phenotype, and social context, these circuits are responsive to a wide range of hormones and neuromodulators acting on different timescales at multiple loci. Bass and Zakon (2005) reviewed the behavioral neuroendocrinology of these two teleost groups, comparing how the regulation of their communication systems have both converged and diverged during their parallel evolution. Here, we revisit this comparison and review the complementary developments over the past 16 years. We (a) summarize recent work that expands our knowledge of the neural circuits underlying these two communication systems, (b) review parallel studies on the action of neuromodulators (e.g., serotonin, AVT, melatonin), brain steroidogenesis (via aromatase), and social stimuli on the output of these circuits, (c) highlight recent transcriptomic studies that illustrate how contemporary molecular methods have elucidated the genetic regulation of social behavior in these fish, and (d) describe recent studies of mochokid catfish, which use both vocal and electric communication, and that use both vocal and electric communication and consider how these two systems are spliced together in the same species. Finally, we offer avenues for future research to further probe how similarities and differences between these two communication systems emerge over ontogeny and evolution.

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Weakly Electric Fish: Behavior, Neurobiology, and Neuroendocrinology

Cited by 10 publications

References 209 publications

Electrostatic Tuning of a Potassium Channel in Electric Fish

Electrostatic Tuning of a Potassium Channel in Electric Fish

Genes linked to species diversity in a sexually dimorphic communication signal in electric fish

Vocal and Electric Fish: Revisiting a Comparison of Two Teleost Models in the Neuroethology of Social Behavior

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