Multiple actions of anandamide on neonatal rat cultured sensory neurones
Multiple actions of anandamide on neonatal rat cultured sensory neurones
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DOI：
10.1038/sj.bjp.0705723
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发表时间：
2004-04-01
影响因子：
7.3
通讯作者：
Ross, RA
中科院分区：
文献类型：
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作者：
Evans, RM;Scott, RH;Ross, RA
我们研究了内源性大麻素anandamide （AEA）对新生大鼠背根神经节神经元兴奋性和香草样TRPV1受体的影响利用全细胞膜片钳电生理学，我们发现在没有CB1受体拮抗剂SR141716A （100 nM）的情况下，AEA抑制高压激活的Ca2+电流33+/-9%（8个神经元中的5个），而在SR141716A.3存在的情况下，AEA抑制高压激活的Ca2+电流32+/-6%（10个神经元中的7个）Fura-2荧光Ca2+成像显示，AEA对30 mM KCl引起的去极化Ca2+瞬态产生明显的影响。在较大的染色体面积（372+/-20 mum）的神经元群体中(2)，它显著增强Ca2+瞬态（80.26+/-13.12%，在1 mum），这种效果在百日咳毒素预处理后持续存在。在较小的染色体面积（279+/-18 mum）的神经元群体中，AEA显著抑制Ca2+瞬态（1 mum时30.75+/-3.54%），这一效应被PTX预处理消除在对辣椒素（1 muM）有反应的8个神经元中，有7个细胞外施加100 nM的AEA未能激发TRPV1受体向内电流，平均向内电流为-0.94+/-0.21 nA。相比之下，细胞内应用100 nM的AEA在62%的神经元中引发了强劲的内向电流，平均群体反应为-0.85+/-0.21 nA。用辣椒素（1 μ m）作用于胞内环境时，平均种群向内电流为-0.01+/-0.01 nA。在对照条件下，观察到-0.09+/-0.05 nA的平均种群电流波动。
1 We have investigated the effects of the endocannabinoid anandamide ( AEA) on neuronal excitability and vanilloid TRPV1 receptors in neonatal rat cultured dorsal root ganglion neurones.2 Using whole-cell patch-clamp electrophysiology, we found that AEA inhibits high-voltage-activated Ca2+ currents by 33+/-9% (five out of eight neurones) in the absence of the CB1 receptor antagonist SR141716A (100 nM) and by 32+/-6% (seven out of 10 neurones) in the presence of SR141716A.3 Fura-2 fluorescence Ca2+ imaging revealed that AEA produced distinct effects on Ca2+ transients produced by depolarisation evoked by 30 mM KCl. In a population of neurones of larger somal area (372+/-20 mum(2)), it significantly enhanced Ca2+ transients (80.26+/-13.12% at 1 muM), an effect that persists after pertussis toxin pretreatment. In a population of neurones of smaller somal area (279+/-18 mum(2)), AEA significantly inhibits Ca2+ transients (30.75+/-3.54% at 1 muM), an effect that is abolished by PTX pretreatment.4 Extracellular application of 100 nM AEA failed to evoke TRPV1 receptor inward currents in seven out of eight neurones that responded to capsaicin (1 muM), with a mean inward current of -0.94+/-0.21 nA. In contrast, intracellular application of 100 nM AEA elicited robust inward currents in similar to62% of neurones, the mean population response was -0.85+/-0.21 nA. When AEA was applied to the intracellular environment with capsazepine (1 muM), the mean population inward current was -0.01+/-0.01 nA. Under control conditions, mean population current fluctuations of -0.09+/-0.05 nA were observed.