Fig. 1.
Brightfield photomicrographs of μ-opioid receptor (MOR1) immunoreactive type 1 astrocytes at 6 days in vitro. MOR1 immunoreactivity was typically punctate with some faint, diffuse immunoreactivity occasionally outlining the plasma membrane and/or adjacent cytoplasm (a,c) Intense immunostaining was often associated with the juxtanuclear cytoplasm (c). The intensity of MOR1 immunoreactivity varied among individual astrocytes; some cells lacked immunoproduct (not clearly shown here). MOR1 immunoreactivity was absent in preabsorbed controls (b). Greater than 95% of the flat, polyhedral cells were glial fibrillary acidic protein-immunoreactive (d). Scale bars: 10 μm (a and b); 25 μm (c), 25 μm (d). Unmodified brightfield optics (a,b,d); differential interference contrast optics (c). Arrows = astrocytes.
