FIG. 4.
The κ-opioid antagonist nor-BNI blocks Dyn A and Dyn B inhibition of [3H]thymidine incorporation into 7-day fetal rat brain cell aggregates. Aggregates were prepared from embryonic day 15 fetal rat brain and grown as described in Materials and Methods and Fig. 1. Dynorphins (1 μM) and/or 0.1 μM nor-BNI were added after 5 days together with protease inhibitors, and [3H]thymidine was present for the last 24 h. Data are the mean ± SEM values of three experiments. *Significantly different from control or nor-BNI–treated aggregates, p < 0.05.