Effects of systemic bicuculline or morphine on formalin-evoked pain-related behaviour and c-Fos expression in trigeminal nuclei after formalin injection into the lip or tongue in rats
Effects of systemic bicuculline or morphine on formalin-evoked pain-related behaviour and c-Fos expression in trigeminal nuclei after formalin injection into the lip or tongue in rats
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DOI：
10.1007/s00221-009-1842-1
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发表时间：
2009-05
影响因子：
2
通讯作者：
S. Sugiyo;D. Uehashi;F. Satoh;Tetsuya Abe;Norifumi Yonehara;Masayuki Kobayashi;M. Takemura
中科院分区：
文献类型：
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作者：
S. Sugiyo;D. Uehashi;F. Satoh;Tetsuya Abe;Norifumi Yonehara;Masayuki Kobayashi;M. Takemura
本研究探讨唇和舌之间的伤害性反应的差异。福尔马林诱导的疼痛相关行为和三叉神经尾侧核（Vc）中的c-Fos表达，有/没有全身性预先给予γ-氨基丁酸（GABA）A型受体拮抗剂荷包牡丹碱（2 mg/kg，i. p.，福尔马林注射前10分钟）或μ-阿片受体激动剂吗啡（3 mg/kg，i. p.，福尔马林注射前10分钟）。将福尔马林注射到上唇中诱导了立即的疼痛相关行为，主要是摩擦面部行为，持续15分钟（阶段1，平均值± SEM/5分钟，81.2 ± 30.1），随后是15分钟的更多增加的活动（阶段2，205.4 ± 43.6），并且在接下来的15分钟内下降至基线（阶段3，63.9 ± 28.0）。福尔马林注射到舌中在第1阶段诱导了相似量的疼痛相关行为（67.9 ± 16.7），随后在第2阶段诱导了相似的活动（48.6 ± 6.2），在第3阶段诱导了较少的行为（20.4 ± 7.6）。当福尔马林注射到唇中时（B，62.5 ± 14.5; m，95.8 ± 10.0），而不注射到舌中时（B，31.0 ± 9.2; m，77.4 ± 27.0），预先给予荷包牡丹碱或吗啡后，第2相的行为减少。福尔马林注射后2 h，在Vc浅层尾侧和内外侧中间（Vc Ⅰ/Ⅱ;平均值± SEM/切片= 225.8 ± 12.9）和Vc大细胞区（Vc Ⅲ/Ⅳ; 67.1 ± 4.7）中诱导出大量c-Fos免疫反应（IR）细胞。福尔马林舌内注射后，在VcI/II区（72.6 ± 3.7）和VcIII/IV区（55.6 ± 6.6）的吻侧和背内侧1/4区，c-Fos-IR细胞的数量明显减少。预先给予荷包牡丹碱或吗啡后，福尔马林注入唇（VcI/II，102.4 ± 8.0; VcIII/IV，32.8 ± 1.4）比注入舌（VcI/II，49.5 ± 8.1; VcIII/IV，31.7 ± 5.3）更能减少福尔马林诱导的VcI/II区c-Fos-IR细胞。这些结果表明，嘴唇比舌头对福尔马林引起的伤害性刺激更敏感，并且更多地通过GABA A和μ阿片受体进行调节。
This study examined differences in nociceptive responses between lip and tongue. Formalin-induced pain-related behaviour and c-Fos expression in the trigeminal caudal nucleus (Vc) with/without systemic preadministration of a γ-aminobutyric acid (GABA) type A receptor antagonist, bicuculline (2 mg/kg, i.p., 10 min before formalin injection) or a μ-opioid receptor agonist, morphine (3 mg/kg, i.p., 10 min before formalin injection) have been studied. Formalin injection into the upper lip induced an immediate pain-related behaviour, mostly face-rubbing behaviour, for 15 min (phase 1, mean ± SEM/5 min, 81.2 ± 30.1), followed by a more increased activity for 15 min (phase 2, 205.4 ± 43.6) and a decline to baseline for next 15 min (phase 3, 63.9 ± 28.0). Formalin injection into the tongue induced similar amount of pain-related behaviour at phase 1 (67.9 ± 16.7), followed by similar activity at phase 2 (48.6 ± 6.2), and lesser behaviour at phase 3 (20.4 ± 7.6). The behaviour at phase 2 decreased following preadministration of bicuculline or morphine when formalin was injected into the lip (b, 62.5 ± 14.5; m, 95.8 ± 10.0) but not into the tongue (b, 31.0 ± 9.2; m, 77.4 ± 27.0). A considerable numbers of c-Fos-immunoreactive (IR) cells were induced in the caudal and inter-medio-lateral center of superficial layers of the Vc (VcI/II; mean ± SEM/section = 225.8 ± 12.9) and magnocellular zone of the Vc (VcIII/IV; 67.1 ± 4.7) 2 h after formalin injection into the lip. Much smaller numbers of c-Fos-IR cells were induced in the rostral and dorso-medial one-fourth of the VcI/II (72.6 ± 3.7) and VcIII/IV (55.6 ± 6.6) after formalin injection into the tongue. Following preadministration with systemic bicuculline or morphine, the formalin-induced c-Fos-IR cells were decreased more in the VcI/II when formalin was injected into the lip (VcI/II, 102.4 ± 8.0; VcIII/IV, 32.8 ± 1.4) than into the tongue (VcI/II, 49.5 ± 8.1; VcIII/IV, 31.7 ± 5.3). These results show that the lip is more sensitive to formalin-induced noxious stimulation and regulated more through GABAAand μ-opioid receptors than the tongue.