Phenanthrene disrupts calcium transients and inhibits INCX in zebrafish ( Danio rerio ) ventricular myocytes

Phenanthrene is a polycyclic aromatic hydrocarbon (PAH) that is derived from fossil fuels and is present in most PAH mixtures found in water, air and soil. It has been shown to affect cardiac function of vertebrates, including fish. We investigated the effects of phenanthrene on intracellular calcium transient ([Ca2+]i) and the Na+/Ca2+ exchanger (NCX) current (INCX) in zebrafish (Danio rerio) ventricular cardiomyocytes using Fluo-4 AM imaging and whole-cell patch-clamp, respectively. Phenanthrene exposure (25 µM) reduced the amplitude and slowed the rate of decay of Ca²⁺ transients. Phenanthrene also inhibited INCX with equal efficacy in forward- and reverse-mode. We conclude that phenanthrene disrupts Ca²⁺ handling in zebrafish ventricular myocytes, which could impact cardiac contractility.