AVT and IT regulate ion transport across the opercular epithelium of killifish (Fundulus heteroclitus) and gilthead sea bream (Sparus aurata). | - CCMAR -

Journal Article

TitleAVT and IT regulate ion transport across the opercular epithelium of killifish (Fundulus heteroclitus) and gilthead sea bream (Sparus aurata).
Publication TypeJournal Article
AuthorsMartos-Sitcha, JAntonio, MartínezRodríguez, G, Mancera, JMiguel, Fuentes, J
Year of Publication2015
JournalComp Biochem Physiol A Mol Integr Physiol
Volume182
Date Published2015 Apr
Pagination93-101
ISSN1531-4332
KeywordsAnimals, Benzazepines, Bumetanide, Chlorides, Dose-Response Relationship, Drug, Epithelium, Fish Proteins, Fundulidae, Indoles, Ion Transport, Oxytocin, Pyrrolidines, Receptors, Vasopressin, Sea Bream, Vasotocin
Abstract

The regulatory role of arginine vasotocin (AVT) and isotocin (IT) in Cl(-) secretion was investigated with the short circuit current (Isc) technique in opercular epithelia of killifish (Fundulus heteroclitus) and gilthead sea bream (Sparus aurata). Sea bream operculum showed ~4-fold lower number of Na/K-ATPase immunoreactive cells and ~12-fold lower secretory current than the killifish. In sea bream opercular membranes, the basolateral addition of AVT (10(-6) M) significantly stimulated Cl(-) secretion, while IT (10(-6) M) was without effect. In killifish, IT produced an immediate dose-dependent stimulation of Cl(-) secretion with significant effect at doses ≥10(-7) M and stimulation maxima (∆Isc ~25 μA⋅cm(-2)) at 10(-6) M. The basolateral addition of bumetanide (200 μM) abolished >75% of the effect of IT on Cl(-) secretion. In turn, AVT had a dual effect on killifish opercular Isc: an immediate response (~3min) with Isc reduction in an inverted bell-shaped dose-response manner with higher current decrease (-22 μA⋅cm(-2)) at 10(-8) M AVT, and a sustained dose-dependent stimulation of Cl(-) secretion (stable up to 1h), with a threshold significant effect at 10(-8) M and maximal stimulation (~20 μA⋅cm(-2)) at 10(-6)M. Both effects of AVT appear receptor type specific. The V1-receptor antagonist SR 49059 abolished Isc reduction in response to AVT, while the specific V2-receptor antagonist (Tolvaptan, 1 μM) abolished the stimulatory action of AVT on Cl(-) secretion. According to these results, we propose a modulatory role for AVT and IT in Cl(-) (NaCl) secretion across the opercular epithelium of marine teleost.

DOI10.1016/j.cbpa.2014.12.027
Sapientia

http://www.ncbi.nlm.nih.gov/pubmed/25536332?dopt=Abstract

Alternate JournalComp. Biochem. Physiol., Part A Mol. Integr. Physiol.
PubMed ID25536332
CCMAR Authors