Pharmacology. In the article “Nuclear localization of prostaglandin E₂ receptors” by Mousumi Bhattacharya, Krishna G. Peri, Guillermina Almazan, Alfredo Ribeiro-da-Silva, Hitoshi Shichi, Yves Durocher, Mark Abramovitz, Xin Hou, Daya R. Varma, and Sylvain Chemtob, which appeared in number 26, December 22, 1998, of Proc. Natl. Acad. Sci. USA (95, 15792–15797), the paragraph on page 15793, left column, should read as follows (change indicated in italic type): “Indirect Immunofluorescence of EP₁ Receptors. For examining the immunolocalization of EP₁ receptors, immunocytochemistry was performed as described (21) on Swiss 3T3, HEK293 (EBNA), or endothelial cells with rabbit anti-EP₁ antibodies (22) and FITC-conjugated or Texas red-conjugated anti-rabbit IgG (Bio/Can Scientific, Mississauga, ON), diluted 1:50.” In addition, because Figs. 6 and 7 were printed with markedly poor quality, they and their legends are reproduced below.

Figure 6.

Immunoperoxidase and immunogold localization of EP₁ in porcine endothelial cells detected by electron microscopy (arrows). (a) Immunoperoxidase-IgG alone; note absence of immunostaining when primary antibody is omitted. (b) A low magnification showing immunostaining in plasma membrane and nuclear envelope. (c) A higher magnification showing immunostaining in the nuclear envelope. (d) Immunogold-IgG alone; note absence of immunostaining. Specific immunostaining can be observed in the plasma membrane in e, nuclear envelope in f, and Golgi apparatus in g. (Bar = 0.5 μm, except in b = 2 μm.)

Figure 7.

Immunoperoxidase localization of EP₁ in adult rat brain cortex by electron microscopy (arrows). Specific immunostaining observed in plasma membrane and inner and outer nuclear membranes of capillary endothelial cell (a) and nuclear membranes of neurons (b). Note the luminal space of capillary on right in a. (Bars = 0.5 μm.)