Dibutyl phthalate rapidly alters calcium homeostasis in the gills of Danio rerio.

This study investigates the impacts of exposure to an environment Ca challenge and the mechanism of action of dibutyl phthalate (DBP) on Ca influx in the gills of Danio rerio. In vitro profile of Ca influx in gills was verified through the basal time-course. Fish were exposed to low, normal and high Ca concentrations (0.02, 0.7 and 2 mM) for 12 h. So, gills were morphologically analysed and ex vivoCa influx at 30 and 60 min was determined. For the in vitro studies, gills were treated for 60 min with DBP (1 pM, 1 nM and 1 μM) with/without blockers/activators of ionic channels, Ca chelator, inhibitors of ATPases, ionic exchangers and protein kinase C to study the mechanism of DBP-induced Ca influx. Exposure to high environmental Ca augmented Ca influx when compared to fish exposed to normal and low Ca concentrations. Additionally, histopathological changes were observed in the gills of fish maintained for 12 h in low and high Ca. In vitro exposure of gills to DBP (1 pM) disturbed Ca homeostasis. DBP stimulated Ca influx in gills through the transitory receptor potential vanilloid 1 (TRPV1), and reverse-mode Na/Ca exchanger (NCX) activation, protein kinase C and K channels and sarco/endoplasmic reticulum Ca-ATPase (SERCA). These data suggest that in vivo short-term exposure of gills to low and high Ca leads to Ca influx and histopathological changes. Additionally, the DBP-induced rapid Ca influx is mediated by TRPV1, NCX activation with the involvement of PKC, K-channels and SERCA, thereby altering Ca homeostasis.