Fig. 1.
Opioid receptor immunoreactivity in neuronal precursors. (A–E) Cerebellar external granule layer (EGL) neuronal precursors expressed μ (A) and δ (C) opioid receptor immunoreactivity in brightfield photomicrographs; however, few, if any, cells were κ immunoreactive (E) at 48 h in vitro. Specific immunoreactivity was not present in μ (B) or δ (E) preabsorbed controls. Scale bar = 15 μm. (F) The proportion of EGL cells expressing μ and δ opioid receptor immunoreactivity was similar at 48 h and 7 days in vitro.