Related Experiment Videos
Chronic morphine treatment inhibits oxytocin synthesis in rats
1Department of Neurobiology, Second Military Medical University, Shanghai, PR China.
Abstract:
The changes of oxytocin content and mRNA expression in some nuclei were investigated in morphine-dependent rats using radioimmunoassay (RIA) and in situ hybridization (ISH). After chronic administration of morphine, the oxytocin content in supraoptic nucleus (SON) and nucleus accumbens (NAc) decreased, and increased in the ventral tegment area (VTA) and locus coeruleus (LC), but did not change in other nuclei including the paraventricular nucleus (PVN), lateral septum (SEPTUM), raphe magnus nucleus (NRM) and periaquaductal gray (PAG). In morphine-L dependent rats, naloxone increased the levels of oxytocin in SON and PVN, but decreased that in LC. ISH first showed that chronic morphine treatment inhibited the oxytocin synthesis in SON but not in PVN. The present study demonstrates that chronic morphine treatment alters the brain oxytocin system, suggesting that oxytocin might contribute to the behavioral and neuroendocrine responses to morphine.
Insights
Chronic morphine alters brain oxytocin levels and synthesis in specific nuclei. This suggests oxytocin plays a role in morphine
Area of Science:
- Neuroscience
- Pharmacology
- Endocrinology
Background:
- Opioid dependence involves complex neurochemical changes.
- The role of oxytocin in opioid-induced effects is not fully understood.
Purpose of the Study:
- To investigate the impact of chronic morphine on brain oxytocin content and mRNA expression.
- To explore the modulation of oxytocin by naloxone in morphine-dependent rats.
Main Methods:
- Radioimmunoassay (RIA) for oxytocin content measurement.
- In situ hybridization (ISH) for oxytocin mRNA expression analysis.
- Utilized a rat model of morphine dependence.
Main Results:
- Chronic morphine decreased oxytocin in the supraoptic nucleus (SON) and nucleus accumbens (NAc), while increasing it in the ventral tegmental area (VTA) and locus coeruleus (LC).
- Naloxone administration reversed some of these changes, increasing oxytocin in SON and paraventricular nucleus (PVN) and decreasing it in LC.
- ISH revealed that chronic morphine inhibited oxytocin synthesis in SON.
Conclusions:
- Chronic morphine administration significantly alters the brain oxytocin system.
- Oxytocin may be involved in the behavioral and neuroendocrine responses to morphine.
- These findings highlight a potential link between the oxytocin system and opioid addiction mechanisms.