Cytochemical and Ultrastructural Characteristics of BHK-21 Cells Exposed to Dopamine

Abstract

BHK-21 cells were incubated in medium containing dopamine (DA) and catecholamine contents were then measured using the Falck cytochemical method. As compared with controls, significant increases were seen in the fluorescence of cells and these were proportional to the concentration and duration of exposure to DA and more marked in cells in suspension than in attached cells. Parallel electron microscopic studies showed that the increased fluorescence intensity of the cytoplasm correlated with the presence of dense networks of fibrils which were identified on the basis of morphological characteristics as microfilaments consisting of F-actin. Prior blockade of dopaminergic receptors with haloperidol did not alter the subsequent effects of DA on fluorescence intensity or cell ultrastructure. These data suggest that, in conditions of chronic exposure, DA can penetrate into the cytoplasm, inducing actin polymerization and becoming bound to the newly formed actin cytoskeleton. Structurally, this can be apparent as hypertrophy of the cytoskeleton and its derivatives, with significant influences on the overall structure of the cell.