Fig. 1. Redistribution of ß-adrenergic receptor immunoanalogue in isoproterenol-treated Paramecium cells, viewed by confocal microscopy. (A) Control cells, (B) isoproterenol-treated cells (10 µmol l^–1) immunolabeled with antibodies against human ß₂-adrenoreceptor and processed for confocal microscopy as described in Materials and methods. ß-adrenergic sites undergo translocation from the cell membrane (A) to the cytoplasmic compartment upon isoproterenol treatment (B). Bar, 15 µm.