FIG. 5.
Effect of increasing concentrations of morphine on Purkinje cell numbers in explants derived from 1-day-old mice. Purkinje cells were counted and their numbers compared in bilaterally-matched paired-explant cultures. One explant within a matched-pair was given nutrient medium alone, while the other explant was continuously treated with morphine, morphine plus naloxone, or naloxone alone for 7 to 10 days in vitro. Note that the reduction in cell numbers caused by 10-5 M morphine was prevented by concurrent treatment with 3 × 10−5 M naloxone (Morph/Nal), while naloxone (3 × 10−5 M) alone had no effect compared to untreated controls. Each determination was made from multiple matched-explant pairs sampled from 12 mice. *P < 0.05 vs. untreated control.