Rhodamine B accumulation and MXR protein expression in mussel blood cells:effects of exposure to vincristine

Mussel hemocytes accumulate rhodamine B within their lysosomal compartment. This intracellular retention, detected and quantified by computerised confocal microscopy, is enhanced by the presence of verapamil. Study of 2 different populations showed alteration in rhodamine B retention and simultaneous differential expression levels of proteins immunorelated to the multidrug resistance (MDR) transporter in relation to their environment. Chronic exposure of animals to the Vinca antitumor alkaloid vincristine causes the hemocytes to accumulate less rhodamine B, to be more sensitive to verapamil and to express more MDR-related proteins. These data add consistency to prevlous results on multixenobiotic resistance in mussels.