Anatomy and physiology of chemesthesis

Saunders, Cecil J.; Silver, Wayne L.

doi:10.1002/9781118951620.ch5

Cited by 3 publications

(2 citation statements)

References 102 publications

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“…What are the molecular and cellular mechanisms of enhanced chemosensation in digging sea robins? Free nerve endings are typically associated with mechanosensation and chemesthesis (thermal, nociceptive, and tactile sensations) 9 , but not the detection of appetitive stimuli like the amino acids that elicit digging behavior. Early retrograde tracing of nerve endings in legs demonstrated that neuron cell bodies reside in dramatically enlarged spinal dorsal root ganglia (DRG), which connect to six novel spinal cord lobes that are specific to each leg 10 ( Fig.…”

Section: Molecular and Cellular Basis Of Sensory Adaptationmentioning

confidence: 99%

Evolution of novel sensory organs in fish with legs

Allard,

Herbert,

Krueger

et al. 2023

Preprint

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How do animals evolve new traits? Sea robins are unusual 'walking' fishes that use leg-like appendages to navigate the seafloor. Here, we show that legs are bona fide sense organs that mediate the unique ability to localize and uncover buried prey. We then probe the developmental and physiological basis of these novel sense organs as a striking example of a major trait gain in evolution. We find certain sea robin species have legs with unique end-organs called papillae that mediate enhanced mechanical and chemical sensitivity to enable predatory digging behavior. Papillae exhibit dense innervation from touch-sensitive neurons, noncanonical epithelial taste receptors, and chemical sensitivity that drives predatory digging behavior. Using a combination of developmental analyses, crosses between species with and without papillae, and interspecies comparisons of sea robins from around the world, we demonstrate that papillae represent a key evolutionary innovation associated with behavioral niche expansion on the seafloor. These discoveries provide a conceptual framework for understanding how molecular, cellular, and tissue-scale adaptations integrate to produce novel organismic traits and behavior.

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Section: Molecular and Cellular Basis Of Sensory Adaptationmentioning

confidence: 99%

Evolution of novel sensory organs in fish with legs

Allard,

Herbert,

Krueger

et al. 2023

Preprint

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“…Several studies have demonstrated that allyl isothiocyanate (AITC) and other compounds are repellent to a variety of earthworm species in the field (Pelosi et al, 2009;Pelosi et al, 2014;Singh, Singh & Vig, 2016;Singh et al, 2018;Silver et al, 2019). However, these chemicals were likely aversive due to the stimulation of polymodal nociceptors (i.e., ''pain fibers''), which mediate the sense of chemesthesis (Richards, Saunders & Silver, 2010;Saunders & Silver, 2016), rather than stimulation of the gustatory or olfactory systems in earthworms. Purported chemosensory organs are concentrated on the head and prostomium, and found on every segment in multiple species (Knapp & Mill, 1971;Kiszler et al, 2012), but no study has ever demonstrated that these organs are, in fact, capable of detecting any chemicals.…”

Section: Introductionmentioning

confidence: 99%

Dendrobaena veneta avoids ethyl pentanoate and ethyl hexanoate, two compounds produced by the soil fungus Geotrichum candidum

Reed

O'Connor

Johnson³

et al. 2021

PeerJ

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Earthworms shape the biological and physicochemical qualities of the soil they choose to reside in, but our understanding of the specific chemicals that attract or repel a particular species of earthworm remains incomplete. Current research indicates that some species feed on and are attracted to fungi, such as Geotrichum candidum. In the present study, as part of our continuing effort to characterize mechanisms of earthworm chemosensation, we tested whether ethyl hexanoate and ethyl pentanoate, two compounds produced by G. candidum, are appetitive to the European nightcrawler (Dendrobaena veneta). In a soil T-maze, both of these compounds significantly repelled individual earthworms in a dosage-dependent manner, this result ran counter to our initial hypothesis. D. veneta also avoided ethyl hexanoate and ethyl pentanoate in an assay we specifically developed to test an earthworms aversion to chemical stimuli in soil. In both of these assays, ethyl hexanoate was aversive at lower concentrations than ethyl pentanoate. These findings further clarify our understanding of the chemical cues that trigger the decision of D. veneta to select a particular soil-environment, and emphasize that different earthworm species may react very differently to commonly encountered chemical stimuli.

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Individual Variation in PROP Status, Fungiform Papillae Density, and Responsiveness to Taste Stimuli in a Large Population Sample

et al. 2018

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Despite considerable research investigating the role of 6-n-propylthiouracil bitterness perception and variation of fungiform papillae density in food perception, this relationship remains controversial as well as the association between the 2 phenotypes. Data from 1119 subjects (38.6% male; 18-60 years) enrolled in the Italian Taste project were analyzed. Responsiveness to the bitterness of 6-n-propylthiouracil was assessed on the general Labeled Magnitude Scale. Fungiform papillae density was determined from manual counting on digital images of the tongue. Solutions of tastes, astringent, and pungent sensations were prepared to be moderate/strong on a general Labeled Magnitude Scale. Four foods had tastants added to produce 4 variations in target sensations from weak to strong (pear juice: citric acid, sourness; chocolate pudding: sucrose, sweetness; bean purée: sodium chloride, saltiness; and tomato juice: capsaicin, pungency). Women gave ratings to 6-n-propylthiouracil and showed fungiform papillae density that was significantly higher than men. Both phenotype markers significantly decreased with age. No significant correlations were found between 6-n-propylthiouracil ratings and fungiform papillae density. Fungiform papillae density variation does not affect perceived intensity of solutions. Responsiveness to 6-n-propylthiouracil positively correlated to perceived intensity of most stimuli in solution. A significant effect of fungiform papillae density on perceived intensity of target sensation in foods was found in a few cases. Responsiveness to 6-n-propylthiouracil positively affected all taste intensities in subjects with low fungiform papillae density whereas there were no significant effects of 6-n-propylthiouracil in those with high fungiform papillae density. These data highlight a complex interplay between 6-n-propylthiouracil status and fungiform papillae density and the need of a critical reconsideration of their role in food perception and acceptability.

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Anatomy and physiology of chemesthesis

Cited by 3 publications

References 102 publications

Evolution of novel sensory organs in fish with legs

Evolution of novel sensory organs in fish with legs

Dendrobaena veneta avoids ethyl pentanoate and ethyl hexanoate, two compounds produced by the soil fungus Geotrichum candidum

Individual Variation in PROP Status, Fungiform Papillae Density, and Responsiveness to Taste Stimuli in a Large Population Sample

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