Susceptibility to abnormal (kinetotic) swimming fish correlates with inner ear carbonic anhydrase-reactivity.
Larval cichlid fish (Oreochromis mossambicus) were kept at hypergravity (hg; centrifuge) for 6 h. Following the transfer to 1 g (i.e. stopping the centrifuge), animals were separated into normally and abnormally (kinetotic) swimming individuals (the latter were swimming kinetotically, i.e. performing spinning movements). Subsequently, carbonic anhydrase- (CA-) reactivity was histochemically demonstrated and densitometrically determined in inner ear maculae. It was found that both the total macular CA-reactivity as well as the difference in reactivates between left and right maculae were significantly lower in normally swimming hg-animals as compared to the kinetotically behaving hg-fish (P<0.0001). This result is in complete agreement with closely related studies carried out on the calcium incorporation of inner ear otoliths and indicates that a regulatory mechanism, which adjusts otolithic calcium carbonate incorporation towards the gravity vector, acts via activation/deactivation of macular CA.
Beier
Marion
M
Zoological Institute, University of Stuttgart-Hohenheim, Garbenstr. 30, D-70593 Stuttgart, Germany.
Anken
Ralf H
RH
Rahmann
Hinrich
H
D008267:Acoustic Maculae / Q000201:enzymology; D000818:Animals; D002256:Carbonic Anhydrases / Q000378:metabolism*; D002498:Centrifugation; D007758:Ear, Inner / Q000201:enzymology*; D018471:Hypergravity; D009043:Motor Activity; D013550:Swimming; D017210:Tilapia
D002256:Carbonic Anhydrases