Fine structure of the fish chloride cell associated with both acute and chronic exposure to mercury

Abstract

Prior cytopathologic studies have demonstrated the sensitivity of fish respiratory and transporting epithelia to mercurials. Despite a well-documented role in extrarenal osmoregulation, the specific involvement of the teleost chloride cell in mercurialism has not been reported. This paper describes the response of this primary filament cell versus acute and chronic exposure to mercuric chloride. The estuarine fish (Fundulus heteroclitus) was used as the target organism. Locally-collected male mummichogs (3. 5-4. 5 g) were acclimated in the laboratory two weeks prior to use. For acute contaminations fish were incubated in artificial seawater containing one of three concentrations of mercury (0. 25, 0. 75 and 1. 50 mg/1) at 20 C and 20 o/oo salinity. In a similar manner other fish were exposed for 30 days to an environmental concentration of toxicant (0. 05 mg/1). Gill tissues of survivors at 12, 36 and 96 hours (acute) and 30 days (chronic) plus controls were fixed for three hours in cold 4% phosphate-buffered glutaraldehyde, postfixed in 1% osmium tetroxide and subsequently embedded in Epon 812.