TY - JOUR ID - 32755 TI - A Study on the Effect of Intracuneiformis Nucleus Microinjection of GABAA Receptor Agonist and Antagonist on Antinociceptive Effects of Morphine by Formalin Test in Rat JO - Journal of Kerman University of Medical Sciences JA - JKMU LA - en SN - 1023-9510 AU - Rezvanipour, M AU - Safari, T AU - Abasnejad, M AD - Assistant Professor of Physiology, Kerman University of Medical Sciences and Health Services, Kerman, Iran AD - Faculty Member, Physiology Department, Birjand University of Medical Sciences and Health Services, Birjand, Iran AD - Assistant Professor of Physiology, Biology Department, Bahonar University of Kerman, Kerman, Iran Y1 - 2005 PY - 2005 VL - 11 IS - 2 SP - 212 EP - 218 KW - Cuneiformis nucleus KW - Morphine KW - Muscimol KW - Bicuculline KW - Pain DO - N2 - In the present study, the effects of intracuneiformis nucleus microinjection of gamma-aminobutyric acidA (GABAA) receptor agonist and antagonist on antinociception inducced by morphine were investigated with formalin test in rat. Intracuneiformis nucleus microinjection of morphine (10µgr/rat) and Bicuculline (50, 100 ng/rat) induced antinociception in the both first and second phases of formalin test. Muscimol (25,50,100 ngr/rat ) produced antinociception only in the second phase of formalin test. Morphine in combination with muscimol but not with bicuculline elicited potentiation. The responses induced by muscimol were not affected by bicuculline. The opioid receptor antagonist (naloxone) did not reduce the response induced by muscimol in the both first and second phases of formalin test. It may be concluded that central GABAA receptor stimulation induced antinociception in formalin test. However, the antinociception induced by GABAA receptor agonist may be partly mediated through nucleus cuneiformis opioid receptor mechanisms. The apparent antinociceptive effects of muscimol may be due to its leakage to rostal portion of Cnf and reduction in motion activity, so have no relation to its real antinociceptive effects. UR - https://jkmu.kmu.ac.ir/article_32755.html L1 - https://jkmu.kmu.ac.ir/article_32755_089c73fa62127c4a8323033d52e7b878.pdf ER -