Emerit M B, Riad M, Fattaccini C M, Hamon M
INSERM U288, Neurobiologie Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
J Neurochem. 1993 Jun;60(6):2059-67. doi: 10.1111/j.1471-4159.1993.tb03490.x.
In the presence of substance P (SP; 10 microM), serotonin (5-HT; 1 microM) triggered a cation permeability in cells of the hybridoma (mouse neuroblastoma x rat glioma) clone NG 108-15 that could be assessed by measuring the cell capacity to accumulate [14C]guanidinium for 10-15 min at 37 degrees C. In addition to 5-HT (EC50 0.33 microM), the potent 5-HT3 receptor agonists 2-methyl-serotonin, phenylbiguanide, and m-chlorophenylbiguanide, and quipazine, markedly increased [14C]guanidinium uptake in NG 108-15 cells exposed to 10 microM SP. In contrast, 5-HT3 receptor antagonists prevented the effect of 5-HT. The correlation (r = 0.97) between the potencies of 16 different ligands to mimic or prevent the effects of 5-HT on [14C]guanidinium uptake, on the one hand, and to displace [3H]zacopride specifically bound to 5-HT3 receptors on NG 108-15 cells, on the other hand, clearly demonstrated that [14C]guanidinium uptake was directly controlled by 5-HT3 receptors. Various compounds such as inorganic cations (La3+, Mn2+, Ba2+, Ni2+, and Zn2+), D-tubocurarine, and memantine inhibited [14C]guanidinium uptake in NG 108-15 cells exposed to 5-HT and SP, as expected from their noncompetitive antagonistic properties at 5-HT3 receptors. However, ethanol (100 nM), which has been reported to potentiate the electrophysiological response to 5-HT3 receptor stimulation, prevented the effects of 5-HT plus SP on [14C]guanidinium uptake. The cooperative effect of SP on this 5-HT3-evoked response resulted neither from an interaction of the peptide with the 5-HT3 receptor binding site nor from a possible direct activation of G proteins in NG 108-15 cells. Among SP derivatives, [D-Pro9]SP, a compound inactive at the various neurokinin receptor classes, was the most potent to mimic the stimulatory effect of SP on [14C]guanidinium uptake in NG 108-15 cells exposed to 5-HT. Although the cellular mechanisms involved deserve further investigations, the 5-HT-evoked [14C]guanidinium uptake appears to be a rapid and reliable response for assessing the functional state of 5-HT3 receptors in NG 108-15 cells.
在存在P物质（SP；10微摩尔）的情况下，血清素（5-羟色胺，5-HT；1微摩尔）可触发杂交瘤（小鼠神经母细胞瘤×大鼠胶质瘤）克隆NG 108-15细胞的阳离子通透性，这可通过测量细胞在37℃下积累[14C]胍10 - 15分钟的能力来评估。除了5-HT（半数有效浓度EC50为0.33微摩尔）外，强效的5-HT3受体激动剂2-甲基血清素、苯基双胍、间氯苯基双胍和喹哌嗪，可显著增加暴露于10微摩尔SP的NG 108-15细胞中[14C]胍的摄取。相比之下，5-HT3受体拮抗剂可阻止5-HT的作用。一方面，16种不同配体模拟或阻止5-HT对[14C]胍摄取作用的效力，与另一方面它们特异性置换与NG
