Daily variations of the saccular endolymph and plasma compositions in the turbot Psetta maxima: relationship with the diurnal rhythm in otolith formation
|Author(s)||Edeyer Anaick, de Pontual Helene, Payan P, Troadec Herve, Severe Armelle, Mayer-Gostan N|
|Affiliation(s)||IFREMER, DRV RH LASAA, Lab Sclerochronol Animaux Aquat, F-29280 Plouzane, France.
IFREMER, DRV RA, Physiol Poissons Lab, F-29280 Plouzane, France.
Univ Nice, CNRS, Lab Physiol & Toxicol Environm, EA 2138, F-06108 Nice, France.
Univ Nice, CNRS, UMR 6548, Lab Physiol Cellulaire & Mol, F-06108 Nice 2, France.
|Source||Marine Ecology Progress Series (0171-8630) (Inter-research), 2000 , Vol. 192 , P. 287-294|
|WOS© Times Cited||26|
|Keyword(s)||daily cycle, endolymph, otolith, chemical composition, teleost|
|Abstract||We studied the circadian variations of the ionic composition ([Na+], [K+], [Cl-]), total CO2 ([tot CO2]), and protein concentration ([protein]) in the plasma and endolymph in the distal and proximal sides of the sacculus in the turbot Psetta maxima. Daily variations in total plasma calcium ([tot Ga]) were also recorded. Significant diurnal fluctuations occurred in most parameters and the spatial heterogeneity of the endolymph composition was maintained throughout a 24 h period. The main parameters implicated in otolith calcification, endolymph [tot CO2] and endolymph [protein], fluctuated diurnally, [tot CO2] was highest and [protein] lowest at night; the relative concentrations were reversed during the day. The inverse, alternating relationship of maximal and minimal [tot CO2] and [protein] implies that calcium carbonate and organic matrix rates of deposition vary in antiphase. We therefore propose that in the turbot P. maxima, in autumn, the incremental zone (L-zone) is formed at night whereas the discontinuous zone (D-zone) is formed during the daytime.|