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Baclofen reestablishes micro-opioid receptor levels modified by morphine withdrawal syndrome in either sex.

Authors :
Diaz SL
Kemmling AK
Bonavita CD
Rubio MC
Balerio GN
Source :
Synapse (New York, N.Y.) [Synapse] 2004 Oct; Vol. 54 (1), pp. 24-9.
Publication Year :
2004

Abstract

We have previously shown that the GABA(B) agonist baclofen (BAC) prevents the expression of morphine (MOR) withdrawal syndrome in male as well as female mice. In addition, we have demonstrated that BAC reestablishes the dopamine levels modified by MOR withdrawal syndrome in male mice. The aim of the present study was to evaluate the micro-opioid receptor binding parameters in striatum and frontal cortex of male and female mice during MOR withdrawal and its prevention with BAC. Prepubertal Swiss-Webster mice of either sex were rendered dependent by intraperitoneal (i.p.) injection of MOR (2 mg/kg) twice daily for 9 days. On the tenth day, dependent animals received naloxone (NAL) (6 mg/kg, i.p.) 60 min after the last dose of MOR and another pool of dependent mice received BAC (2 mg/kg, i.p.) previous to NAL injection. Thirty min after NAL or saline injection mice were sacrificed, brains were collected, and the striatum and frontal cortex were dissected in order to perform binding studies with [(3)H][DAMGO]. The density of micro-opioid receptor increased significantly during MOR withdrawal in male and female striatum as well as in male cortex. In addition, in both brain areas the B(max) was higher in male than in female mice during MOR withdrawal. Finally, BAC pretreatment of MOR withdrawn mice reestablished the levels of micro-opioid receptor by significantly decreasing the B(max) in either sex. In conclusion, although there were sex differences in the micro-opioid receptor density during MOR withdrawal syndrome, BAC was able to reestablish the changes in binding parameters induced by the NAL-precipitated withdrawal in female and male mice.

Details

Language :
English
ISSN :
0887-4476
Volume :
54
Issue :
1
Database :
MEDLINE
Journal :
Synapse (New York, N.Y.)
Publication Type :
Academic Journal
Accession number :
15300881
Full Text :
https://doi.org/10.1002/syn.20061