[Met⁵]enkephalin and δ₂-opioid receptors in the spinal cord are involved in the cold water swimming-induced antinociception in the mouse

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• 作者：Mizoguchi ; Hirokazu ; Narita ; Minoru ; Kampine ; John P. ; Tseng ; Leon F.
• 关键词：cold water swimming ; antinociception ; δ ; ₂-opioid receptors ; [Met⁵]enkephalin ; spinal cord ; mouse
• 刊名：Life Sciences
• 出版年：1997
• 期刊代码：62_00243205
• 类别：imm
• 出版时间：July 11, 1997
• 卷：61
• 期：7
• 页码：PL81-PL86
• 文件大小：429 K

摘要

Mice made cold water swimming (CWS: 4 °C, 3 min) produced an opioid-mediated antinociception. Experiments were designed to determine what types of opioid receptors and endogenous opioid peptides in the spinal cord are involved in the CWS-induced antinociception in male ICR mice. Antinociception was measured by the tail-flick test. CWS-induced antinociception was blocked by intrathecal (i.t.) pretreatment with antiserum to [Met⁵enkephalin (100 μg, 1 hr), but not by antiserum (100 μg, 1 hr) to [Leu⁵]enkephalin, β-endorphin or dynorphin A (1-17). Moreover, i.t. pretreatment with δ₂-opioid receptor antagonist naltriben (NTB: 10 μg, 10 min) blocked the antinociception induced by CWS or i.t.-administered [Met⁵]enkephalin (10 μg). However, the antinociception induced by CWS or i.t.-administered [Met⁵]enkephalin was not blocked by i.t. pretreatment with δ₁-opioid receptor antagonist 7-benzylidene naltrexone (BNTX: 1 μg, 10 min), μ-opioid receptor antagonist d-Phe-Cys-Try-d-Try-Orn-Thr-Phe-Thr-NH₂ (CTOP: 50 ng, 10 min), or κ-opioid receptor antagonist norbinaltorphimine (norBNI: 5 μg, 24 hr). These data indicate that [Met⁵]enkephalin and δ₂-opioid receptor in the spinal cord are involved in antinociception induced by CWS.