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Agonist regulation of the expression of the delta opioid receptor in NG108‐15 cells
Author(s) -
Kim Dong Sun,
Chin Hemin,
Klee Werner A.
Publication year - 1995
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(95)01233-6
Subject(s) - agonist , δ opioid receptor , chemistry , opioid , delta , receptor , opioid receptor , pharmacology , neuroscience , microbiology and biotechnology , psychology , biochemistry , biology , physics , astronomy
Exposure of neuronal cells to the chronic presence of opiates leads to a complex series of biochemical events which reflect the changes that result in tolerance and dependence in animals. To achieve a better understanding of the molecular mechanisms underlying these processes, we have examined the effect of agonist efficacy on the regulation of the δ‐opioid receptor mRNA in NG108‐15 cells. Incubation with various opiates decreased receptor numbers in the order of their efficacy. Northern blot analysis showed that there are 4 size classes of mRNA coding for the δ‐opioid receptor in NG108‐15 cells even though only one known protein species is found. Moreover, the amount of each transcript is coordinately decreased by long‐term etorphine treatment, but not necessarily to the same extent. The etorphine‐induced decrease in receptor mRNA was found to be slow in onset, whereas a much more rapid loss of receptor number was observed. This disparity suggests that the down‐regulation induced by etorphine can occur both at the levels of receptor protein modification and receptor gene expression, and that the mechanisms of the two processes may be different.