Western blot analysis was conducted to determine whether the changes in 5-HT3 protein followed the observed changes in Htr3a mRNA. This analysis showed that protein preparations from the brainstems of C57BL/6J mice had statistically significant decreases in 5-HT3 content after morphine treatment, whereas no such changes were observed in preparations made from 129/SvlmJ mice (Fig. 8).
