Decrease of morphine-CPP by sinomenine via mediation of tyrosine hydroxylase, NMDA receptor subunit 2B and opioid...

Area of Science:

• Neuroscience
• Pharmacology
• Addiction Research

Background:

• Morphine dependence is a significant global health issue.
• Understanding the neurobiological mechanisms of opioid-induced addiction is crucial.
• Zebrafish models offer a powerful platform for studying addiction-related behaviors and molecular changes.

Purpose of the Study:

• To investigate the therapeutic potential of sinomenine in mitigating morphine-induced conditioned place preference (CPP) in zebrafish.
• To examine the effects of sinomenine on the expression of key neurochemical markers, including tyrosine hydroxylase (TH), NMDA receptor subunit 2B (NR2B), and opioid receptors (μ-opioid receptor (zfmor), δ-opioid receptors (zfdor1 and zfdor2)).

Main Methods:

• Morphine was administered to induce CPP in zebrafish.
• Sinomenine and methadone were used as pre-treatments.
• Conditioned place preference was assessed through behavioral observation.
• Immunohistochemistry was employed to detect TH and NR2B expression.
• RT-qPCR was utilized to quantify mRNA levels of opioid receptors in the zebrafish brain.

Main Results:

• Morphine administration induced significant behavioral alterations indicative of CPP.
• Sinomenine and methadone pre-treatments significantly reduced activity in the morphine-paired compartment.
• Morphine increased TH and NR2B expression while decreasing opioid receptor levels.
• Sinomenine treatment attenuated these morphine-induced changes, downregulating TH and NR2B and upregulating opioid receptors.

Conclusions:

• Sinomenine (80mg/kg) significantly attenuates morphine-induced CPP in zebrafish.
• Sinomenine modulates the expression of TH, NR2B, and opioid receptors, suggesting a role in addiction pathways.
• These findings highlight sinomenine as a potential therapeutic agent for opioid use disorder.