Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test
ABSTRACTPrevious studies have shown the role of opioid receptors located in the nucleus cuneiformis (CnF) in acute pain, but not in chronic pain models. In the present study, we have determined that possible effects of these receptors at the CnF on both early and late phases of formalin test followi...
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| Format: | Article |
| Language: | English |
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Iran University of Medical Sciences
2010-11-01
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| Series: | Basic and Clinical Neuroscience |
| Subjects: | |
| Online Access: | http://bcn.tums.ac.ir/browse.php?a_code=A-10-2-4&slc_lang=en&sid=1 |
| _version_ | 1797285031315505152 |
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| author | Abbas Haghparast Leila Ahmad-Molaei Amir-Mohammad Alizadeh Pegah Azizi |
| author_facet | Abbas Haghparast Leila Ahmad-Molaei Amir-Mohammad Alizadeh Pegah Azizi |
| author_sort | Abbas Haghparast |
| collection | DOAJ |
| description | ABSTRACTPrevious studies have shown the role of opioid receptors located in the nucleus cuneiformis (CnF) in acute pain, but not in chronic pain models. In the present study, we have determined that possible effects of these receptors at the CnF on both early and late phases of formalin test following local and systemic morphine administration. Each rat was given a subcutaneous 50-μl injection of 2.5% formalin into plantar surface of hind paw. Ninety five Wistar rats bilaterally received morphine (1, 2, 4 and 8 μg/0.3 μl saline per side) into the CnF, just before the formalin test. Naloxone (1 μg/0.3 μl saline per side) was also microinjected 2 minutes before local or 28 minutes after intraperitoneal administration of morphine. The results showed that bilateral intra-CnF administration of morphine dose-dependently produced analgesia in formalin test. Naloxone administration into the CnF antagonized the analgesic response induced by morphine (4 μg/0.3 μl saline) microinjection. The results also showed that analgesic effect of systemic morphine was not significantly decreased by naloxone microinjection. We suggest that the opioid receptors located in the CnF, in part, indirectly affect the morphine-induced descending pain modulatory circuit. |
| first_indexed | 2024-03-07T17:56:20Z |
| format | Article |
| id | doaj.art-fab151a4202c46b6adebd0b90af36077 |
| institution | Directory Open Access Journal |
| issn | 2008-126X 2228-7442 |
| language | English |
| last_indexed | 2024-03-07T17:56:20Z |
| publishDate | 2010-11-01 |
| publisher | Iran University of Medical Sciences |
| record_format | Article |
| series | Basic and Clinical Neuroscience |
| spelling | doaj.art-fab151a4202c46b6adebd0b90af360772024-03-02T12:15:57ZengIran University of Medical SciencesBasic and Clinical Neuroscience2008-126X2228-74422010-11-01211319Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin TestAbbas HaghparastLeila Ahmad-MolaeiAmir-Mohammad AlizadehPegah AziziABSTRACTPrevious studies have shown the role of opioid receptors located in the nucleus cuneiformis (CnF) in acute pain, but not in chronic pain models. In the present study, we have determined that possible effects of these receptors at the CnF on both early and late phases of formalin test following local and systemic morphine administration. Each rat was given a subcutaneous 50-μl injection of 2.5% formalin into plantar surface of hind paw. Ninety five Wistar rats bilaterally received morphine (1, 2, 4 and 8 μg/0.3 μl saline per side) into the CnF, just before the formalin test. Naloxone (1 μg/0.3 μl saline per side) was also microinjected 2 minutes before local or 28 minutes after intraperitoneal administration of morphine. The results showed that bilateral intra-CnF administration of morphine dose-dependently produced analgesia in formalin test. Naloxone administration into the CnF antagonized the analgesic response induced by morphine (4 μg/0.3 μl saline) microinjection. The results also showed that analgesic effect of systemic morphine was not significantly decreased by naloxone microinjection. We suggest that the opioid receptors located in the CnF, in part, indirectly affect the morphine-induced descending pain modulatory circuit.http://bcn.tums.ac.ir/browse.php?a_code=A-10-2-4&slc_lang=en&sid=1Nucleus CuneiformisOpioid ReceptorMorphineNaloxoneFormalin TestPain |
| spellingShingle | Abbas Haghparast Leila Ahmad-Molaei Amir-Mohammad Alizadeh Pegah Azizi Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test Basic and Clinical Neuroscience Nucleus Cuneiformis Opioid Receptor Morphine Naloxone Formalin Test Pain |
| title | Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test |
| title_full | Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test |
| title_fullStr | Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test |
| title_full_unstemmed | Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test |
| title_short | Blockade of Opioid Receptors Located in the Rat Nucleus Cuneiformis Reduced the Antinociceptive Responses of Local But not Systemic Administration of Morphine in Formalin Test |
| title_sort | blockade of opioid receptors located in the rat nucleus cuneiformis reduced the antinociceptive responses of local but not systemic administration of morphine in formalin test |
| topic | Nucleus Cuneiformis Opioid Receptor Morphine Naloxone Formalin Test Pain |
| url | http://bcn.tums.ac.ir/browse.php?a_code=A-10-2-4&slc_lang=en&sid=1 |
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