The present study was designed to shed light in the involvement of AVT on ion regulatory processes in the intestine of marine fish. In order to substantiate the putative endocrine action of AVT in the gastrointestinal tract (GIT), a fragment of one of the receptors was cloned in the gilthead sea bream (Sparus aurata). The presence of the AVT receptor (AVTR) mRNA was demonstrated along the GIT. In addition, a salinity and region dependent expression of AVTR was demonstrated by semiquantitative PCR. Physiological analysis, using in vitro Ussing chambers for the characterization of the bioelectrical properties of the tissue, demonstrated differential functional responses to AVT according to intestinal region and environmental salinity. The AVT threshold effective dose in vitro was 10-8 M, in agreement with the circulating plasma levels described previously for the sea bream. Taken together, all these results demonstrate a role for AVT in ion regulation in the GIT of the euryhaline marine species S. aurata.

Study funded by FCT (Portugal) project PTDC/MAR/104008/2008 to JF, and by grant AGL2010-14876 (Ministerio de Ciencia e Innovación, Spain) to JMM. JAM-S is supported by a predoctoral frellowship (FPU, Reference AP2008-01194) from Ministry of Education (Spain).

Trabajo presentado en el 8º Congreso de la Asociación Ibérica de Endocrinología Comparada (AIEC), celebrado en Madrid del 5 al 7 de septiembre de 2011.

Peer Reviewed