The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats
Introduction: The role of serotonergic fibers in avoidance learning is controversial. Involvement of the dorsal raphe nucleus (DRN), the main source of hippocampal projecting serotonergic fibers in acquisition, consolidation and retrieval of passive avoidance (PA) learning, was investigated by funct...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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Iran University of Medical Sciences
2011-08-01
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| Series: | Basic and Clinical Neuroscience |
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| Online Access: | http://bcn.tums.ac.ir/browse.php?a_code=A-10-1-73&slc_lang=en&sid=1 |
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| author | Amir Hossein Emam Abbas Haghparast Alireza Komaki Siamak Shahidi Nasser Naghdi Gila Behzadi Iraj Salehi Behnam Heshmatian Meisam Yazdi Abdolrahman Sarihi |
| author_facet | Amir Hossein Emam Abbas Haghparast Alireza Komaki Siamak Shahidi Nasser Naghdi Gila Behzadi Iraj Salehi Behnam Heshmatian Meisam Yazdi Abdolrahman Sarihi |
| author_sort | Amir Hossein Emam |
| collection | DOAJ |
| description | Introduction: The role of serotonergic fibers in avoidance learning is controversial. Involvement of the dorsal raphe nucleus (DRN), the main source of hippocampal projecting serotonergic fibers in acquisition, consolidation and retrieval of passive avoidance (PA) learning, was investigated by functional suppression of this area. Materials and Methods: DRN functional inactivation was done by lidocaine (0.5μl, 2%) injection into the DRN, 5 min before training (n=10); and 5 (n=9), 90 (n=10) and 360 min (n=9) after acquisition trial. In the last experiment, lidocaine was injected into the DRN 5 min before the retrieval test , which was 48 h after the training (n=10). Results: Our results showed that PA learning was not impaired by DRN inactivation 5 min before training nor 5 and 360 min after training. Lidocaine injected 90 min after the acquisition trial significantly reduced avoidance of the dark compartment (P<0.001). Intra-DRN injection of lidocaine before retrieval significantly increased PA retention (P<0.001). Therefore, it seems that DRN has opposite effects on consolidation and retrieval of passive avoidance learning, but it has no effect on PA acquisition. Discussion: It is suggested that functional ablation of DRN may disrupt integrity of subcortical circuits participating in PA consolidation, but DRN inactivation by increasing brain awareness may affect PA retrieval in rats. |
| first_indexed | 2024-03-07T16:40:33Z |
| format | Article |
| id | doaj.art-9828820b5af64938892ee4102fa169d6 |
| institution | Directory Open Access Journal |
| issn | 2008-126X 2228-7442 |
| language | English |
| last_indexed | 2024-03-07T16:40:33Z |
| publishDate | 2011-08-01 |
| publisher | Iran University of Medical Sciences |
| record_format | Article |
| series | Basic and Clinical Neuroscience |
| spelling | doaj.art-9828820b5af64938892ee4102fa169d62024-03-03T08:32:12ZengIran University of Medical SciencesBasic and Clinical Neuroscience2008-126X2228-74422011-08-01242735The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in RatsAmir Hossein EmamAbbas HaghparastAlireza KomakiSiamak ShahidiNasser NaghdiGila BehzadiIraj SalehiBehnam HeshmatianMeisam YazdiAbdolrahman SarihiIntroduction: The role of serotonergic fibers in avoidance learning is controversial. Involvement of the dorsal raphe nucleus (DRN), the main source of hippocampal projecting serotonergic fibers in acquisition, consolidation and retrieval of passive avoidance (PA) learning, was investigated by functional suppression of this area. Materials and Methods: DRN functional inactivation was done by lidocaine (0.5μl, 2%) injection into the DRN, 5 min before training (n=10); and 5 (n=9), 90 (n=10) and 360 min (n=9) after acquisition trial. In the last experiment, lidocaine was injected into the DRN 5 min before the retrieval test , which was 48 h after the training (n=10). Results: Our results showed that PA learning was not impaired by DRN inactivation 5 min before training nor 5 and 360 min after training. Lidocaine injected 90 min after the acquisition trial significantly reduced avoidance of the dark compartment (P<0.001). Intra-DRN injection of lidocaine before retrieval significantly increased PA retention (P<0.001). Therefore, it seems that DRN has opposite effects on consolidation and retrieval of passive avoidance learning, but it has no effect on PA acquisition. Discussion: It is suggested that functional ablation of DRN may disrupt integrity of subcortical circuits participating in PA consolidation, but DRN inactivation by increasing brain awareness may affect PA retrieval in rats.http://bcn.tums.ac.ir/browse.php?a_code=A-10-1-73&slc_lang=en&sid=1Dorsal RaphePassive AvoidanceReversible InactivationLearning And MemoryLidocaineRat |
| spellingShingle | Amir Hossein Emam Abbas Haghparast Alireza Komaki Siamak Shahidi Nasser Naghdi Gila Behzadi Iraj Salehi Behnam Heshmatian Meisam Yazdi Abdolrahman Sarihi The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats Basic and Clinical Neuroscience Dorsal Raphe Passive Avoidance Reversible Inactivation Learning And Memory Lidocaine Rat |
| title | The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats |
| title_full | The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats |
| title_fullStr | The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats |
| title_full_unstemmed | The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats |
| title_short | The Effects of Lidocaine Reversible Inactivation of the Dorsal Raphe Nucleus on Passive Avoidance Learning in Rats |
| title_sort | effects of lidocaine reversible inactivation of the dorsal raphe nucleus on passive avoidance learning in rats |
| topic | Dorsal Raphe Passive Avoidance Reversible Inactivation Learning And Memory Lidocaine Rat |
| url | http://bcn.tums.ac.ir/browse.php?a_code=A-10-1-73&slc_lang=en&sid=1 |
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