Analysis of the action of oxytocin at synapse level in regulating nociceptive transmission in rat spinal dorsal horn

2014 Fiscal Year Final Research Report

• Project/Area Number: 24500461
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Neurophysiology and muscle physiology
• Research Institution: Saga University
• Principal Investigator: KUMAMOTO Eiichi 佐賀大学, 医学部, 教授 (60136603)
• Co-Investigator(Kenkyū-buntansha): FUJITA Tsugumi 佐賀大学, 医学部, 准教授 (70336139)
• Project Period (FY): 2012-04-01 – 2015-03-31
• Keywords: オキシトシン / 鎮痛 / 脊髄後角 / 興奮性シナプス伝達 / 抑制性シナプス伝達 / 脱分極 / ラット / パッチクランプ法

Outline of Final Research Achievements

We examined how oxytocin affects synaptic transmission in substantia gelatinosa (SG) neurons by applying the patch-clamp technique to the SG neurons of adult rat spinal cord slices. Bath-applied oxytocin unaffected excitatory transmission while producing an inward current at -70 mV and enhancing spontaneous inhibitory transmission. These activities were mimicked by oxytocin-receptor agonist. The oxytocin current was inhibited by oxytocin-receptor antagonist, U-73122, 2-aminoethoxydiphenyl borate but not dantrolene, chelerythrine, dibutyryl cyclic-AMP and tetrodotoxin, while the spontaneous inhibitory transmission enhancement was depressed by tetrodotoxin. It is concluded that oxytocin produces a membrane depolarization mediated by oxytocin receptors, which increases neuronal activity, resulting in the enhancement of inhibitory transmission, a possible mechanism for antinociception. This depolarization is possibly mediated by phospholipase C and IP3-induced Ca2+-release.

Free Research Field

神経生理学