Development of a vibrational startle response assay for screening environmental pollutants and drugs impairing predator avoidance

AbstractStartle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behavior. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously contract the body and raise the parapodia. The startle response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.Short SummaryThe neuronal circuitry of the Platynereis startle response links polycystin-dependent hydrodynamic sensors to muscle and ciliary effector cells

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Neural circuitry of a polycystin-mediated hydrodynamic startle response for predator avoidance

eLife ◽

10.7554/elife.36262 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 15

Author(s):

Luis A Bezares-Calderón ◽

Jürgen Berger ◽

Sanja Jasek ◽

Csaba Verasztó ◽

Sara Mendes ◽

...

Keyword(s):

Startle Response ◽

Predator Avoidance ◽

Receptor Cell ◽

Neural Circuitry ◽

Whole Body ◽

Wiring Diagram ◽

Planktonic Larva ◽

Simultaneous Activation ◽

Receptor Neurons ◽

Effector Response

Startle responses triggered by aversive stimuli including predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously raise the parapodia. The response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in predator avoidance.

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A high-throughput assay for screening environmental pollutants and drugs impairing predator avoidance in Daphnia magna

The Science of The Total Environment ◽

10.1016/j.scitotenv.2020.140045 ◽

2020 ◽

Vol 740 ◽

pp. 140045 ◽

Cited By ~ 1

Author(s):

Juliette Bedrossiantz ◽

Fernando Martínez-Jerónimo ◽

Marina Bellot ◽

Demetrio Raldua ◽

Cristian Gómez-Canela ◽

...

Keyword(s):

Daphnia Magna ◽

High Throughput ◽

Predator Avoidance ◽

Environmental Pollutants ◽

High Throughput Assay

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Polychlorinated biphenyl induced hepatocyte alterations

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010012789x ◽

1987 ◽

Vol 45 ◽

pp. 716-717

Author(s):

D.N. Collins ◽

J.N. Turner ◽

K.O. Brosch ◽

R.F. Seegal

Keyword(s):

Lipid Droplets ◽

Wistar Rats ◽

Homovanillic Acid ◽

Polychlorinated Biphenyl ◽

Corn Oil ◽

Environmental Pollutants ◽

Short Term ◽

Pcb Congeners ◽

Urinary Levels ◽

The Brain

Polychlorinated biphenyls (PCBs) are a ubiquitous class of environmental pollutants with toxic and hepatocellular effects, including accumulation of fat, proliferated smooth endoplasmic recticulum (SER), and concentric membrane arrays (CMAs) (1-3). The CMAs appear to be a membrane storage and degeneration organelle composed of a large number of concentric membrane layers usually surrounding one or more lipid droplets often with internalized membrane fragments (3). The present study documents liver alteration after a short term single dose exposure to PCBs with high chlorine content, and correlates them with reported animal weights and central nervous system (CNS) measures. In the brain PCB congeners were concentrated in particular regions (4) while catecholamine concentrations were decreased (4-6). Urinary levels of homovanillic acid a dopamine metabolite were evaluated (7).Wistar rats were gavaged with corn oil (6 controls), or with a 1:1 mixture of Aroclor 1254 and 1260 in corn oil at 500 or 1000 mg total PCB/kg (6 at each level).

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Food-Evoked Changes in Humans

Journal of Psychophysiology ◽

10.1027/0269-8803/a000003 ◽

2010 ◽

Vol 24 (1) ◽

pp. 25-32 ◽

Cited By ~ 19

Author(s):

Peter Walla ◽

Maria Richter ◽

Stella Färber ◽

Ulrich Leodolter ◽

Herbert Bauer

Keyword(s):

Food Intake ◽

Startle Response ◽

Brain Activity ◽

Soft Drink ◽

Ice Cream ◽

Response Amplitude ◽

Response Modulation ◽

Motivational States ◽

Localization Analysis ◽

Study Participants

Two experiments investigate effects related to food intake in humans. In Experiment 1, we measured startle response modulation while study participants ate ice cream, yoghurt, and chocolate. Statistical analysis revealed that ice cream intake resulted in the most robust startle inhibition compared to no food. Contrasting females and males, we found significant differences related to the conditions yoghurt and chocolate. In females, chocolate elicited the lowest response amplitude followed by yoghurt and ice cream. In males, chocolate produced the highest startle response amplitude even higher than eating nothing, whereas ice cream produced the lowest. Assuming that high response amplitudes reflect aversive motivation while low response amplitudes reflect appetitive motivational states, it is interpreted that eating ice cream is associated with the most appetitive state given the alternatives of chocolate and yoghurt across gender. However, in females alone eating chocolate, and in males alone eating ice cream, led to the most appetitive state. Experiment 2 was conducted to describe food intake-related brain activity by means of source localization analysis applied to electroencephalography data (EEG). Ice cream, yoghurt, a soft drink, and water were compared. Brain activity in rostral portions of the superior frontal gyrus was found in all conditions. No localization differences between conditions occurred. While EEG was found to be insensitive, startle response modulation seems to be a reliable method to objectively quantify motivational states related to the intake of different foods.

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