μ-Opioid receptor in the CA1 involves in tramadol and morphine cross state-dependent memory
•Pre-train tramadol administration (intra-CA1) induced amnesia.•Tramadol administraton in the hippocampus induced state-dependent memory.•Tramadol and morphine had cross state dependent memory.•Tramadol induced state dependent memory regulated via mu-opioid receptor in the CA1. In the present study,...
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Published in | Neuroscience letters Vol. 705; pp. 177 - 182 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
Ireland
Elsevier B.V
13.07.2019
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Subjects | |
Online Access | Get full text |
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Summary: | •Pre-train tramadol administration (intra-CA1) induced amnesia.•Tramadol administraton in the hippocampus induced state-dependent memory.•Tramadol and morphine had cross state dependent memory.•Tramadol induced state dependent memory regulated via mu-opioid receptor in the CA1.
In the present study, the effect of tramadol – an opioid painkiller drug with abuse potential- on amnesia and state-dependent memory and its interaction with the opioidergic system was investigated in male Wistar rats. Intra CA-1 administration of tramadol (0.5, 1, and 2 μg/rat) before training, dose-dependently decreased the learning ability in passive avoidance task. Amnesia induced by pre-train tramadol administration was significantly reversed by pre-test administration of tramadol (1 μg/rat). Pre-test administration of naltrexone (a μ-opioid receptor (MOR) antagonist) inhibited the effect of tramadol on memory retrieval. In addition, the pre-test administration of morphine (1 μg/rat, intra-CA1) also reversed memory impairment induced by pre-train tramadol administration. Although, pre-train morphine administration (1 μg/rat, intra-CA1), induced memory impairment reversed by pre-test tramadol administration (1 μg/rat, intra-CA1). In addition, the level of MOR in the hippocampus decreased in animals with memory impairment due to using tramadol in the training day. However, state-dependent retrieval using tramadol or cross state-dependent retrieval using morphine enhanced the MOR level in the hippocampus.
The results of the study suggested that intra-CA1 tramadol administration induced memory impairment, improved by pre-test administration of either tramadol or morphine (MOR agonist). It could be concluded that tramadol is capable to induced state-dependent memory and also, it has a cross state-dependent memory with morphine in the hippocampus, done possibly through MOR. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0304-3940 1872-7972 |
DOI: | 10.1016/j.neulet.2019.04.054 |