Differences in the kappa opioid receptor mRNA content in... : NeuroReport (original) (raw)
Molecular Neuroscience
Differences in the kappa opioid receptor mRNA content in distinct brain regions of two inbred mice strains
1Max-Planck-Institute of Psychiatry, Kraepelinst. 2, D-80804 Munich, Germany
2Corresponding Author: Anett Winkler
ACKNOWLEDGEMENTS: The authors wish to thank S.M. Hölter and I. Sillaber for critical reading of the manuscript. This work was supported by grants from BMBF (FKZ 01EB9419).
Received 19 February 1998; accepted 26 February 1998
Abstract
THE inbred C57BL/6 mouse strain is known to prefer an ethanol solution in a two-bottle choice procedure, whereas the inbred DBA/2 mouse strain avoids drinking ethanol in this paradigm. The genetic basis of this behavior is still unclear but the endogenous opioid system is one of the factors thought to be involved. Therefore, we were interested to see if there are basal differences between the two lines of mice in the kappa opioid receptor (κOR) mRNA content in different brain regions. Because of the low expression level of this gene and the limited amount of tissue we developed a sensitive competitive reverse transcription-polymerase chain reaction (RT-PCR) assay for evaluation of levels of κOR mRNA in brain tissue. In septum and hypothalamus the DBA/2 mice showed a significantly higher basal level of κOR mRNA than did C57BL/6 mice. It is suggested that a difference in basal amount of κOR mRNA among these strains could lead to differences in κOR activity and subsequently to variations between the strains in distinct behaviors such as in ethanol preference.
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