Effect of melatonin on the content of β-endorphin in the hypothalamic arcuate nucleus and periaqueductal grey of midbrain in morphine withdrawal mice / 生理学报
Acta Physiologica Sinica
;
(6): 765-769, 2007.
Article
in Chinese
| WPRIM
| ID: wpr-316783
ABSTRACT
The present study was undertaken to investigate the effect of melatonin on the content of β-endorphin (β-EP) in the hypothalamic arcuate nucleus (Arc) and periaqueductal grey (PAG) of midbrain in morphine withdrawal mice. Male Kunming mice were injected subcutaneously (s.c.) with an increasing dose of morphine continuously for 8 d to establish morphine dependence model. Withdrawal response was induced by naloxone (3 mg/kg body weight, s.c.). The potency of withdrawal response was evaluated according to the jumping times and body weight loss. Ninty minutes prior to the precipitation of naloxone, 80 mg/kg body weight of melatonin (MEL) was injected intraperitoneally (i.p.) to observe its antagonistic effect on the withdrawal response in morphine-dependent mice. After behavioral observation, radioimmunoassay was used to determine the content of β-EP in the PAG of midbrain, and immunohistochemical assay was used to observe the intensity of β-EP-like immunoreactivity in the Arc in mice. It was shown that MEL inhibited the naloxone-precipitated withdrawal responses in mice significantly (P<0.05). In the meantime, MEL increased the content of β-EP in the PAG of midbrain significantly (P<0.05) and attenuated the intensity of β-EP-like immunoreactivity in the Arc in mice (P<0.05). The results suggest that MEL increases the content of β-EP in the PAG of midbrain, decrease the content of β-EP in the Arc in morphine withdrawal mice.
Full text:
Available
Index:
WPRIM (Western Pacific)
Main subject:
Pharmacology
/
Substance Withdrawal Syndrome
/
Arcuate Nucleus of Hypothalamus
/
Mesencephalon
/
Periaqueductal Gray
/
Beta-Endorphin
/
Melatonin
/
Metabolism
/
Morphine Dependence
/
Naloxone
Limits:
Animals
Language:
Chinese
Journal:
Acta Physiologica Sinica
Year:
2007
Type:
Article
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