Characteristics of [14C]Guanidinium Accumulation in NG 108-15 Cell Exposed to Serotonin 5-HT3 Receptor Ligands and Substance P
Version of Record online: 5 OCT 2006
Journal of Neurochemistry
Volume 60, Issue 6, pages 2059–2067, June 1993
How to Cite
Emerit, M. B., Riad, M., Fattaccini, C. M. and Hamon, M. (1993), Characteristics of [14C]Guanidinium Accumulation in NG 108-15 Cell Exposed to Serotonin 5-HT3 Receptor Ligands and Substance P. Journal of Neurochemistry, 60: 2059–2067. doi: 10.1111/j.1471-4159.1993.tb03490.x
- Issue online: 5 OCT 2006
- Version of Record online: 5 OCT 2006
- Received July 2 1, 1992; revised manuscript received October 30, 1992; accepted November 2, 1992.
- 5-HT3 receptors;
- NG 108-15 cells;
- Substance P.
Abstract: In the presence of substance P (SP; 10 μM), serotonin (5-HT; 1 μM) 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°C. In addition to 5-HT (EC50, 0.33 μM), 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 μM 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 mM), 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.