Morpho-functional approach to neurotransmission and osmoregulation in Amphibalanus amphitrite cyprid (Cirripedia, Crustacea)

Acorn barnacles are cirripedian crustacea with a sessile adult stage, that live in a calcareous shell attached to a submersed substrate and filter food with its limbs. Barnacles show various naupliar stages and a cyprid, the final lecithotrophic stage competent for settlement. Due to their ability to adhere, barnacles are important constituents of biofouling. To obtain biological data useful to develop antifouling strategies, many studies are focused on cyprid anatomy and neuroendocrinology, especially in Amphibalanus amphitrite due to its worldwide distribution. With our work we wanted to map the distribution of neurotransmitters in the cyprid to provide data for research on barnacle development, new antifouling strategies and the use of cyprid as a model organism in ecotoxicology. We focused on the distribution of neuroactive substances related to different systems: serotonergic, cholinergic, FMRFamidergic-like, GABAergic, glutamatergic and nitrergic. Also the functional aspects were investigated through physiological assessment, pointing out on swimming and settling activities. The cholinergic (our data) and the octopaminergic (from the literature) systems are known as potential target in antifouling strategies; moreover we suggest that serotonergic and GABAergic systems could be pharmacologically targeted as well, because they are widely present in the cyprid sensory and nervous structures. We are now focusing also on osmoregulative processes, attempting to characterize the presence and distribution of aquaporins, as they could be of interest in both antifouling strategies and ecotoxicology. To date, our data are consistent with the literature about ion-exchanging sites in the cyprid.