Hypercapnia and low pH induce neuroepithelial cell proliferation and emersion behaviour in the amphibious fish Kryptolebias marmoratus.
J Exp Biol
; 218(Pt 19): 2987-90, 2015 Oct.
Article
in En
| MEDLINE
| ID: mdl-26254321
ABSTRACT
Aquatic hypercapnia may have helped to drive ancestral vertebrate invasion of land. We tested the hypothesis that amphibious fishes sense and respond to elevated aquatic PCO2 by behavioural avoidance mechanisms, and by morphological changes at the chemoreceptor level. Mangrove rivulus (Kryptolebias marmoratus) were exposed to 1â
week of normocapnic control water (pH 8), air, hypercapnia (5% CO2, pH 6.8) or isocapnic acidosis (pH 6.8). We found that the density of CO2/H(+) chemoreceptive neuroepithelial cells (NECs) was increased in hypercapnia or isocapnic acidosis-exposed fish. Projection area (a measure of cell size) was unchanged. Acute exposure to progressive hypercapnia induced the fish to emerse (leave water) at water pH values â¼6.1, whereas addition of HCl to water caused a more variable response with a lower pH threshold (â¼pH 5.5). These results support our hypothesis and suggest that aquatic hypercapnia provides an adequate stimulus for extant amphibious fishes to temporarily transition from aquatic to terrestrial habitats.
Key words
Full text:
1
Database:
MEDLINE
Main subject:
Behavior, Animal
/
Cyprinodontiformes
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Carbon Dioxide
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Saline Waters
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Neuroepithelial Cells
Limits:
Animals
Language:
En
Year:
2015
Type:
Article