The Differential Effects of Buprenorphine and Methadone on Adolescent Mice.
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This study focuses on understanding the consequences of administering opioid maintenance drugs, such as buprenorphine and methadone, on the adolescent brain. This is because that there are growing needs to treat opioid dependence and addiction in adolescents and there is a lack of studies that aim at explaining the effects of opioid maintenance drugs on the still-developing adolescent brain. The goal of this study is to enable physicians to conduct a science-based risk assessment on the proper use of these treatments for that age group. A recent study conducted in our lab has indicated potential risks in chronic exposure to certain opioids, specifically, morphine during adolescence. Morphine exposure was observed to change the signaling of D2/D3 dopamine receptors in adolescent mice. The D2/D3 dopamine receptor may mediate long-term mental changes in adolescents, specifically changes linked to mood and psychotic disorders. Thus, this study examined whether buprenorphine and methadone alter the responses of the D2/D3 dopamine receptors differently in an adolescent population. Adolescent mice were orally administered buprenorphine, methadone, or saline once daily for 6 days. Two hours or three days later, the mice were tested for their locomotor response to quinpirole, a D2/D3 dopamine receptor agonist. Buprenorphine-treated adolescent mice showed a similar response to that of the drug-naïve (saline-injected) group in their response to quinpirole. In contrast, an enhanced response was observed in methadone-treated adolescent animals. This effect was significantly higher two hours following the final dose of methadone, as compared to three days afterwards. As shown in this study, methadone exposure greatly disturbs the D2/D3 receptor’s signaling. This indicates that care should be taken when administering methadone to adolescents for addiction therapies as well as pain management. In contrast to methadone, buprenorphine appears to disrupt the D2/D3 dopamine receptor signaling in adolescents less. Therefore, this study may confirm that exposure to different opioids carries different risks, specifically in an adolescent population.
Barwatt, Joseph (2013). The Differential Effects of Buprenorphine and Methadone on Adolescent Mice.. Honors and Undergraduate Research. Available electronically from