No significant change of N -methyladenosine modification landscape in mouse brain after morphine exposure.

OBJECTIVES

N -methyladenosine (m A) plays a crucial role in regulating neuroplasticity and different brain functions at the posttranscriptional level. However, it remains unknown whether m A modification is involved in acute and chronic morphine exposure.

MATERIALS AND METHODS

In this study, we conducted a direct comparison of m A levels and mRNA expression of m A-associated factors between morphine-treated and nontreated C57BL/6 wild-type mice. We established animal models of both acute and chronic morphine treatment and confirmed the rewarding effects of chronic morphine treatment using the conditioned place preference (CPP) assay. The activation status of different brain regions in response to morphine was assessed by c-fos staining. To assess overall m A modification levels, we employed the m A dot blot assay, while mRNA levels of m A-associated proteins were measured using a quantitative polymerase chain reaction (qPCR) assay. These analyses were performed to investigate whether and how m A modification and m A-associated protein expression will change following morphine exposure.

RESULTS

The overall m A methylation and mRNA levels of m A-associated proteins were not significantly altered in brain regions that were either activated or not activated during acute morphine stimulation. Similarly, the overall m A modification and mRNA levels of m A-associated proteins remained unaffected in several key brain regions associated with reward following chronic morphine exposure.

CONCLUSION

This study showed that the overall m A modification level and mRNA expression levels of m A-associated factors were not affected after acute and chronic morphine exposure in different brain regions, indicating m A modification may not be involved in brain response to morphine exposure.