FIG. 4.
Effect of increasing concentrations of morphine on Purkinje cell dendritic length in explants derived from 1-day-old mice. Purkinje cell dendritic length was measured and 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 concurrent 3 × 10−5 M naloxone plus 10−5 M morphine (Morph/Nal) treatment prevented morphine-induced deficits in dendritic length, while 3 × 10−5 M naloxone alone had no effect. Eight to 16 Purkinje cells were randomly sampled from each explant in a matched-pair. Determinations were made from explant pairs sampled from 6 mice for each drug concentration or treatment group. *P < 0.05 vs. untreated control.