Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
PLoS One
2022 Sep 07;179:e0273035. doi: 10.1371/journal.pone.0273035.
Show Gene links
Show Anatomy links
Electrophysiological responses to conspecific odorants in Xenopus laevis show potential for chemical signaling.
Rhodes HJ
,
Amo M
.
???displayArticle.abstract???
The fully aquatic African clawed frog, Xenopus laevis, has an unusual and highly adapted nose that allows it to separately sample both airborne and waterborne stimuli. The function of the adult water nose has received little study, despite the fact that it is quite likely to receive information about conspecifics through secretions released into the water and could aid the frog in making decisions about social and reproductive behaviors. To assess the potential for chemical communication in this species, we developed an in situ electroolfactogram preparation and tested the olfactory responses of adult males to cloacal fluids and skin secretions from male and female conspecifics. We found robust olfactory responses to all conspecific stimuli, with greatest sensitivity to female cloacal fluids. These results open the door to further testing to identify compounds within cloacal fluids and skin secretions that are driving these responses and examine behavioral responses to those compounds. Understanding the role of chemical communication in social and reproductive behaviors may add to our rich understanding of vocal communication to create a more complete picture of social behavior in this species.
???displayArticle.pubmedLink???
36070316
???displayArticle.pmcLink???PMC9451071 ???displayArticle.link???PLoS One
Fig 2. Sample experiment timeline.
This timeline represents a short segment of an experiment, illustrating the order and timing of events. Stimuli were injected into a port in the perfusion line (colored dots), traveled down the perfusion line for several seconds, then washed across the olfactory epithelium (“stimulus exposure” period, marked on timeline). EOG responses were observed during this exposure time if evoked by the stimulus. Positive controls (shown in red; amino acids such as methionine and alanine) were used to elicit a strong EOG response at the start and end (not shown) of each recording block. After positive controls or test stimuli, a saline wash was administered to ensure the port and line were clean (white oval). Saline was also used as a negative control (blue). Test stimuli (green) at various dilutions were alternated with negative controls for the bulk of each recording block.
Fig 3. Sample EOG recordings.
EOG traces are shown in response to (A) amino acids, (B) female cloacal fluids, and (C) male cloacal fluids. The stimulus was injected into the perfusion line at the beginning of each trace (indicated with the black caret), creating a small stimulus artifact, with EOG response occurring 6–8 seconds later (large downward deflections). Stimuli and relative concentration are indicated to the right of each trace (A is 1 mM alanine; M is 1 mM methionine; C is cloacal fluid). Control in (A) was saline; controls in (B) and (C) were cloacal-specific controls (saline passed through the cloacal fluid collection process). Scale bar is 1 mV (vertical) and 3 s (horizontal). Data were from Frog 8; summary data can be found on subsequent figures.
Fig 4. EOG responses to different concentrations of methionine.
EOG amplitude, represented as z-score relative to control (saline) stimuli, are shown for 6 individuals across 6 concentrations, ranging from 1 mM to 0.01 μM L-methionine. EOG response declined at lower concentrations, with the detectability threshold (z ≥ 2) falling between 10 and 1 μM for most animals. Individual animals are shown with distinct symbols; light gray horizontal band from z = -2 to z = 2 indicates responses that may not be distinguishable from saline control.
Fig 5. EOG responses to different concentrations of cloacal fluids from female and male conspecifics, represented as z-score relative to cloacal control stimuli.
(A) EOG amplitudes in response to female cloacal fluids were robust at 10−2 concentration, and declined at lower concentrations, with the detectability threshold (z ≥ 2) falling between 10−3 and 10−5 for most animals. (B) EOG amplitudes to male cloacal fluids were far smaller, with a detection threshold between 10−2 and 10−3 for most animals.
Fig 6. EOG responses to skin secretions from female and male conspecifics, represented as z-score relative to skin control stimuli.
(A) EOG amplitudes in response to female skin secretions were well above the detection threshold at concentrations of 10−1 and 10−2, and may still have been detectable for some animals at 10−3 and 10−5. (B) EOG responses to male skin secretions were similar to those seen in A for the most concentrated stimuli, with a detection threshold between 10−2 and 10−3 for most animals.
Breunig,
The endocannabinoid 2-arachidonoyl-glycerol controls odor sensitivity in larvae of Xenopus laevis.
2010, Pubmed,
Xenbase
Breunig,
The endocannabinoid 2-arachidonoyl-glycerol controls odor sensitivity in larvae of Xenopus laevis.
2010,
Pubmed
,
Xenbase
Caprio,
Electrophysiological distinctions between the taste and smell of amino acids in catfish.
1977,
Pubmed
Date-Ito,
Xenopus V1R vomeronasal receptor family is expressed in the main olfactory system.
2008,
Pubmed
,
Xenbase
Demori,
Peptides for Skin Protection and Healing in Amphibians.
2019,
Pubmed
,
Xenbase
Eom,
F-series prostaglandin function as sex pheromones in the Korean salamander, Hynobius leechii.
2009,
Pubmed
Evans,
Genetics, Morphology, Advertisement Calls, and Historical Records Distinguish Six New Polyploid Species of African Clawed Frog (Xenopus, Pipidae) from West and Central Africa.
2015,
Pubmed
,
Xenbase
Fouke,
Electrophysiological and Motor Responses to Chemosensory Stimuli in Isolated Cephalopod Arms.
2020,
Pubmed
Germano,
Urinary hormone analysis assists reproductive monitoring and sex identification of bell frogs (Litoria raniformis).
2009,
Pubmed
Gliem,
Bimodal processing of olfactory information in an amphibian nose: odor responses segregate into a medial and a lateral stream.
2013,
Pubmed
,
Xenbase
Hansen,
Ultrastructure of the olfactory organ in the clawed frog, Xenopus laevis, during larval development and metamorphosis.
1998,
Pubmed
,
Xenbase
Hassenklöver,
Amino acid- vs. peptide-odorants: responses of individual olfactory receptor neurons in an aquatic species.
2012,
Pubmed
,
Xenbase
Heerema,
Use of electro-olfactography to measure olfactory acuity in the North American bullfrog (Lithobates (Rana) catesbeiana) tadpole.
2018,
Pubmed
Houck,
Pheromone communication in amphibians and reptiles.
2009,
Pubmed
Iida,
Responses of Xenopus laevis water nose to water-soluble and volatile odorants.
1999,
Pubmed
,
Xenbase
Joshi,
Spectrophotometric determination of cation concentrations in olfactory mucus.
1987,
Pubmed
Jungblut,
Olfactory subsystems in the peripheral olfactory organ of anuran amphibians.
2021,
Pubmed
,
Xenbase
Kelley,
Vocal communication in frogs.
2004,
Pubmed
Kelley,
Generation, Coordination, and Evolution of Neural Circuits for Vocal Communication.
2020,
Pubmed
,
Xenbase
Kelley,
Probing forebrain to hindbrain circuit functions in Xenopus.
2017,
Pubmed
,
Xenbase
Kikuyama,
Sodefrin: a novel sex pheromone in a newt.
1999,
Pubmed
King,
Characterization of a peptide from skin secretions of male specimens of the frog, Leptodactylus fallax that stimulates aggression in male frogs.
2005,
Pubmed
Manzini,
Response profiles to amino acid odorants of olfactory glomeruli in larval Xenopus laevis.
2007,
Pubmed
,
Xenbase
Menini,
Olfactory Coding in Larvae of the African Clawed Frog Xenopus laevis
2010,
Pubmed
Oikawa,
Fine structure of three types of olfactory organs in Xenopus laevis.
1998,
Pubmed
,
Xenbase
Park,
Discrimination of conspecific sex and reproductive condition using chemical cues in axolotls ( Ambystoma mexicanum).
2004,
Pubmed
Pearl,
Evidence for a mate-attracting chemosignal in the dwarf African clawed frog Hymenochirus.
2000,
Pubmed
Reuter,
A depolarizing chloride current contributes to chemoelectrical transduction in olfactory sensory neurons in situ.
1998,
Pubmed
Rhodes,
Male-male clasping may be part of an alternative reproductive tactic in Xenopus laevis.
2014,
Pubmed
,
Xenbase
Roelants,
Global patterns of diversification in the history of modern amphibians.
2007,
Pubmed
Sansone,
Dual processing of sulfated steroids in the olfactory system of an anuran amphibian.
2015,
Pubmed
,
Xenbase
Siefkes,
Electrophysiological evidence for detection and discrimination of pheromonal bile acids by the olfactory epithelium of female sea lampreys ( Petromyzon marinus).
2004,
Pubmed
Starnberger,
From uni- to multimodality: towards an integrative view on anuran communication.
2014,
Pubmed
Still,
Multimodal stimuli regulate reproductive behavior and physiology in male túngara frogs.
2019,
Pubmed
Syed,
Coordinated shift of olfactory amino acid responses and V2R expression to an amphibian water nose during metamorphosis.
2017,
Pubmed
,
Xenbase
Tobias,
Vocal communication between male Xenopus laevis.
2004,
Pubmed
,
Xenbase
Tobias,
Vocal competition in male Xenopus laevis frogs.
2010,
Pubmed
,
Xenbase
Wabnitz,
Aquatic sex pheromone from a male tree frog.
1999,
Pubmed
Weiss,
Olfaction across the water-air interface in anuran amphibians.
2021,
Pubmed
Woodley,
Chemosignals, hormones, and amphibian reproduction.
2015,
Pubmed