Naslov
The concentrations of inhibitors of multixenobiotic resistance mechanism in natural waters: The direct in vivo demonstration of their effect

Autori
Smital, Tvrtko ; Kurelec, Branko

Izvornik
Environmental toxicology and chemistry (0730-7268) 16 (1997), 10; 2164-2170

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
multixenobiotic resistance; inhibitors; accumulation; rhodamine B; mussel

Sažetak
Xenobiotics in water that can inhibit the multixenobiotic resistance (MXR) defence mechanism in water organisms, the chemosensitizers, may cause severe ecotoxicological effects. We determined their concentrations in polluted and unpolluted river- and sea-waters using different methods. Here we present the method that enables the direct determination of MXR-inhibitory potential in natural waters. This method measures the modulating potential of river-water or sea-water on the rate of rhodamine B (RB) accumulation in gills of a fresh-water clam Dreissena polymorpha or a marine mussel Mytilus galloprovincialis, respectively. The sensitivity of the method with RB enabled even the determination of MXR-inhibitors by measuring their potential to modulate the rate of efflux of RB from gills of mussels. The concentrations of MXR-inhibitors found by these methods, expressed in mM of verapamil equivalents, were higher in natural waters from polluted rivers, or in natural seawaters from polluted marine sites, than in natural waters from unpolluted rivers, or in natural seawaters from unpolluted sites. Polluted waters enhanced accumulation, or decreased efflux-rate of RB, a good substrate of P-glycoprotein, demonstrating that complex mixture of chemicals presents in polluted waters contains the MXR-inhibiting potential. In addition, the efflux-version of the method with RB has the clear advantage that it is non-sacrificiable and allows repeated use of the same individuals. Simultaneously, it represents the simplest and the most reliable method for measurement the activity of MXR in these organisms.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA