丁卡因对大鼠脊髓胶状质中谷氨酸能自发性兴奋性传递的突触前易化作用——TRPA1通道的参与
Presynaptic facilitation by tetracaine of glutamatergic spontaneous excitatory transmission in the rat spinal substantia gelatinosa - Involvement of TRPA1 channels.
作者信息
Piao Lian-Hua, Fujita Tsugumi, Yu Ting, Kumamoto Eiichi
机构信息
Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
Department of Physiology, Saga Medical School, 5-1-1 Nabeshima, Saga 849-8501, Japan.
出版信息
Brain Res. 2017 Feb 15;1657:245-252. doi: 10.1016/j.brainres.2016.12.021. Epub 2016 Dec 23.
The amide-type local anesthetic (LA) lidocaine activates transient receptor potential (TRP) ankyrin-1 (TRPA1) channels to facilitate spontaneous l-glutamate release onto spinal substantia gelatinosa (SG) neurons, which play a crucial role in regulating nociceptive transmission. In contrast, the ester-type LA procaine reduces the spontaneous release of l-glutamate in SG neurons. In order to determine whether TRPA1 activation by LAs is specific to amide-types, we examined the actions of tetracaine, another ester-type LA, and other amide-type LAs on glutamatergic spontaneous excitatory transmission in SG neurons by focusing on TRP activation. Whole-cell patch-clamp recordings were performed on SG neurons of adult rat spinal cord slices at a holding potential of -70mV. Bath-applied tetracaine increased spontaneous excitatory postsynaptic current (sEPSC) frequency in a concentration-dependent manner. Tetracaine activity was resistant to the voltage-gated Na-channel blocker tetrodotoxin, the TRP vanilloid-1 antagonist capsazepine, and the TRP melastatin-8 antagonist BCTC, but was inhibited by the non-selective TRP antagonist ruthenium red and the TRPA1 antagonist HC-030031. With respect to amide-type LAs, prilocaine had a tendency to increase sEPSC frequency, while ropivacaine and levobupivacaine reduced the frequency. In conclusion, tetracaine facilitated spontaneous l-glutamate release from nerve terminals by activating TRPA1 channels in the SG, resulting in an increase in the excitability of SG neurons. TRPA1 activation was not specific to amide-type or ester-type LAs. The facilitatory action of LAs may be involved in pain occurring after recovery from spinal anesthesia.
酰胺型局部麻醉药(LA)利多卡因可激活瞬时受体电位(TRP)锚蛋白1(TRPA1)通道,促进l-谷氨酸自发释放到脊髓胶状质(SG)神经元上,这些神经元在调节伤害性感受传递中起关键作用。相比之下,酯型LA普鲁卡因可减少SG神经元中l-谷氨酸的自发释放。为了确定LA对TRPA1的激活是否对酰胺型具有特异性,我们通过关注TRP激活来研究另一种酯型LA丁卡因以及其他酰胺型LA对SG神经元中谷氨酸能自发兴奋性传递的作用。在成年大鼠脊髓切片的SG神经元上进行全细胞膜片钳记录,钳制电位为-70mV。浴用丁卡因以浓度依赖性方式增加自发兴奋性突触后电流(sEPSC)频率。丁卡因的作用对电压门控钠通道阻滞剂河豚毒素、TRP香草酸受体1拮抗剂辣椒素和TRP褪黑素受体8拮抗剂BCTC具有抗性,但被非选择性TRP拮抗剂钌红和TRPA1拮抗剂HC-030031抑制。关于酰胺型LA,丙胺卡因有增加sEPSC频率的趋势,而罗哌卡因和左旋布比卡因则降低频率。总之,丁卡因通过激活SG中的TRPA1通道促进神经末梢自发释放l-谷氨酸,导致SG神经元兴奋性增加。TRPA1的激活对酰胺型或酯型LA不具有特异性。LA的促进作用可能与脊髓麻醉恢复后出现的疼痛有关。