Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors
Introduction: Beside its autonomic functions, the nucleus paragigantocellularis lateralis (LPGi) is involved in the descending pain modulation. 17β-Estradiol is a neuroactive steroid found in several brain areas such as LPGi. Intra-LPGi microinjection of 17β-estradiol can elicit th...
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| Format: | Article |
| Language: | English |
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Iran University of Medical Sciences
2017-01-01
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| Series: | Basic and Clinical Neuroscience |
| Subjects: | |
| Online Access: | http://bcn.iums.ac.ir/browse.php?a_code=A-10-797-1&slc_lang=en&sid=1 |
| _version_ | 1797282526550556672 |
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| author | Roghaieh Khakpay Maryam Azaddar Fatemeh Khakpay Homeira Hatami Nemati |
| author_facet | Roghaieh Khakpay Maryam Azaddar Fatemeh Khakpay Homeira Hatami Nemati |
| author_sort | Roghaieh Khakpay |
| collection | DOAJ |
| description | Introduction: Beside its autonomic functions, the nucleus paragigantocellularis lateralis (LPGi) is involved in the descending pain modulation. 17β-Estradiol is a neuroactive steroid found in several brain areas such as LPGi. Intra-LPGi microinjection of 17β-estradiol can elicit the analgesic responses. 17β-Estradiol modulates nociception by binding to estrogenic receptors as well as allosteric interaction with other membrane-bound receptors like GABAA receptors. This study aimed to examine the role of GABAA receptors in the pain modulating effect of intra-LPGi injection of 17β-estradiol.
Methods: To study the antinociceptive effects of 17β-estradiol, cannulation into the LPGi nucleus of male Wistar rats was performed. About 500 nL of drug was administered 15 minutes prior to formalin injection (50 μL of 4%). Then, formalin-induced flexing and licking behaviors were recorded for 60 minutes. For evaluating the role of GABAA receptors in the estradiol-induced pain modulation, 17β-estradiol was administered into the LPGi nucleus 15 minutes after the injection of 25 ng/μL bicuculline (the GABAA receptor antagonist). Then, the formalin-induced responses were recorded.
Results: The results of the current study showed that intra-LPGi injection of 17β-estradiol decreased the flexing duration in both phases of formalin test (P<0.001); but it only attenuated the second phase of licking behavior (P<0.001). 17β-estradiol attenuated the second phase of formalin test of both behaviors (P<0.001). Bicuculline prevented the antinociceptive effect
of intra-LPGi 17β-estradiol in both first and second phases of formalin-induced responses (P<0.001).
Conclusion: According to the results of this study, the analgesic effect of intra-LPGi 17β-estradiol on the formalin-induced inflammatory pain might be mediated via GABAA receptors. |
| first_indexed | 2024-03-07T17:15:18Z |
| format | Article |
| id | doaj.art-e1e655601bdb4a0da7c9541b84a16f73 |
| institution | Directory Open Access Journal |
| issn | 2008-126X 2228-7442 |
| language | English |
| last_indexed | 2024-03-07T17:15:18Z |
| publishDate | 2017-01-01 |
| publisher | Iran University of Medical Sciences |
| record_format | Article |
| series | Basic and Clinical Neuroscience |
| spelling | doaj.art-e1e655601bdb4a0da7c9541b84a16f732024-03-02T23:28:18ZengIran University of Medical SciencesBasic and Clinical Neuroscience2008-126X2228-74422017-01-01815160Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA ReceptorsRoghaieh Khakpay0Maryam Azaddar1Fatemeh Khakpay2Homeira Hatami Nemati3 Department of Animal Science, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran. Department of Animal Science, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran. Department of Biology, Faculty of Basics Sciences, Varamin Branch, Islamic Azad University, Pishva, Iran. Department of Animal Science, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran. Introduction: Beside its autonomic functions, the nucleus paragigantocellularis lateralis (LPGi) is involved in the descending pain modulation. 17β-Estradiol is a neuroactive steroid found in several brain areas such as LPGi. Intra-LPGi microinjection of 17β-estradiol can elicit the analgesic responses. 17β-Estradiol modulates nociception by binding to estrogenic receptors as well as allosteric interaction with other membrane-bound receptors like GABAA receptors. This study aimed to examine the role of GABAA receptors in the pain modulating effect of intra-LPGi injection of 17β-estradiol. Methods: To study the antinociceptive effects of 17β-estradiol, cannulation into the LPGi nucleus of male Wistar rats was performed. About 500 nL of drug was administered 15 minutes prior to formalin injection (50 μL of 4%). Then, formalin-induced flexing and licking behaviors were recorded for 60 minutes. For evaluating the role of GABAA receptors in the estradiol-induced pain modulation, 17β-estradiol was administered into the LPGi nucleus 15 minutes after the injection of 25 ng/μL bicuculline (the GABAA receptor antagonist). Then, the formalin-induced responses were recorded. Results: The results of the current study showed that intra-LPGi injection of 17β-estradiol decreased the flexing duration in both phases of formalin test (P<0.001); but it only attenuated the second phase of licking behavior (P<0.001). 17β-estradiol attenuated the second phase of formalin test of both behaviors (P<0.001). Bicuculline prevented the antinociceptive effect of intra-LPGi 17β-estradiol in both first and second phases of formalin-induced responses (P<0.001). Conclusion: According to the results of this study, the analgesic effect of intra-LPGi 17β-estradiol on the formalin-induced inflammatory pain might be mediated via GABAA receptors. http://bcn.iums.ac.ir/browse.php?a_code=A-10-797-1&slc_lang=en&sid=117β-Estradiol GABAA receptor Pain Analgesia |
| spellingShingle | Roghaieh Khakpay Maryam Azaddar Fatemeh Khakpay Homeira Hatami Nemati Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors Basic and Clinical Neuroscience 17β-Estradiol GABAA receptor Pain Analgesia |
| title | Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors |
| title_full | Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors |
| title_fullStr | Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors |
| title_full_unstemmed | Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors |
| title_short | Analgesic Effect of 17β-Estradiol on Nucleus Paragigantocellularis Lateralis of Male Rats Mediated Via GABAA Receptors |
| title_sort | analgesic effect of 17β estradiol on nucleus paragigantocellularis lateralis of male rats mediated via gabaa receptors |
| topic | 17β-Estradiol GABAA receptor Pain Analgesia |
| url | http://bcn.iums.ac.ir/browse.php?a_code=A-10-797-1&slc_lang=en&sid=1 |
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