Cocaine modulates mu-opioid receptor mRNA but not c-fos mRNA levels in primary cortical astrocytes
Section snippets
INTRODUCTION
The opioid peptides, receptors, and their mRNA levels, are regulated by acute and chronic cocaine administration in several areas of the mesocorticolimbic and nigrostriatal pathways 8., 22., 26., 27.. Cocaine administration is shown to increase mu-opioid receptor (MOR) and decrease kappa opioid receptor (KOR) mRNA levels 25., 26., 27. while acute or intermittent cocaine administration increases mRNA and protein levels of several immediate early genes, including c-fos, which may be an initial
Primary Astrocyte Cultures
Primary astrocyte cells were established from the cortex of 1-day-old Fischer rats (Charles River, NY) as previously reported 5., 19.. Briefly, the brains of rat pups were removed and the cortex was dissected and counted by hemocytometer. The cells were seeded in 6 well tissue culture plates with an area of 9.6 cm2 per well (Falcon). Cells were grown for 2–3 weeks and the medium (Dubelcco’s modified eagle medium with l-glutamine, sodium pyruvate, and pyridoxine hydrochloride, containing 10% fetal
RESULTS
Figure 1 shows that more than 98% of the cultured cells expressed GFAP, indicating that they are astrocytes. Figure 2A–C show the effects of 30 min, 2 h, or 5 h of cocaine treatment, on MOR (top) and S16 (bottom) mRNA levels, respectively. Figure 2D shows the mean (±SEM) of MOR levels per S16 levels. Cocaine reduced MOR mRNA levels by 75% after 2 and 5 h of treatment as compared to untreated or 30 min cocaine treated cultures (Fig. 2D). There was no difference between the untreated and 30 min cocaine
DISCUSSION
Even though molecular mechanisms of MOR signaling are not clear, several reports have demonstrated an up-regulation of MOR mRNA levels in several mesocorticolimbic areas after cocaine administration as well as in astrocytes in culture after cytokine administration 19., 20., 26., 27.. However, MOR mRNA levels are significantly reduced after cocaine administration in developing rhesus macaque monkeys while etorphine and retinoic acid produce a biphasic effect on MOR mRNA levels, decreasing MOR
Acknowledgements
This work was supported in part by PS-CUNY, RCMI RR-03037, SCORE 506-GM 60654, MIDARP-DA12136, and SNRP NF-39534.
References (27)
- et al.
Evidence for dopamine D2 receptor mRNA expression by striatal astrocytes in culture: In situ hybridization and polymerase chain reaction studies
Brain Res. Mol. Brain Res.
(1994) - et al.
Chronic prenatal cocaine treatment down-regulates mu-opioid receptor mRNA expression in the brain of fetal Rhesus Macaque
Neurosci. Lett.
(1999) - et al.
Pharmacological characterization and visualization of the glial serotonin transporter
Neurochem. Int.
(2001) - et al.
Regulation of dopamine uptake by basic fibroblast growth factor and epidermal growth factor in cultured rat astrocytes
Neurosci. Res.
(1999) - et al.
Retinoic acid regulation of mu opioid receptor and c-fos mRNAs and AP-1 DNA binding in SH-SY5Y neuroblastoma cells
Mol. Brain Res.
(2002) - et al.
Assessment of delta opioid antinociception and receptor mRNA levels in mouse after chronic naltrexone treatment
Brain Res.
(1995) - et al.
‘Binge’ cocaine administration induces a sustained increase of prodynorphin mRNA in rat caudate-putamen
Mol. Brain Res.
(1993) - et al.
The frequency of cocaine administration impacts cocaine-induced receptor alterations
Brain Res.
(2001) - et al.
Acute “binge” cocaine increases mu-opioid receptor mRNA levels in areas of the rat mesolimbic mesocortical dopamine system
Brain Res. Bull.
(1999) - et al.
Cocaine hepatotoxicity in cultured liver slices: A species comparison
Toxicology
(1990)
In vivo regulation of mu-opioid receptor density and gene expression in CXBX and outbred Swiss Webster mice
Synapse
Amphetamine and cocaine induce drug-specific activation of the c-fos gene in striosome-matrix compartments and limbic subdivisions of the striatum
Proc. Natl. Acad. Sci.
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