- Kooyman, A.R. et al. (1993) Br. J. Pharmacol. 108, 287.
- Alomone Labs 5-Hydroxyindole modulates 5-HT3A receptors expressed in HEK 293T cells.5-HT3A receptor currents were elicited by 1µM 5-HT delivered every 3 minutes. 5-Hydroxyindole (#H-115) was applied 30 seconds before stimulation at 0.3 mM, as indicated, and inhibited the 5-HT induced peak current but increased the duration of the current response to 5-HT.
Serotonin (5-hydroxytryptamine, 5-HT) is a monoamine neurotransmitter synthesized from the amino acid tryptophan by the enzyme tryptophan-decarboxylase. 5-HT3 receptor is a ligand-gated ion channel receptor of the cys-loop channel family. It is a pentamer with five subunits surrounding a central pore1.
5-Hydroxyindole (5-indolol) is a synthetic, allosteric modulator of 5-HT3 channels. It has an effective concentration of 100 μM – 1 mM for 5-HT3A. 5-Hydroxyindole was tested in N1E-115 (neuroblastoma cells) and does not seem to elicit 5-HT receptor mediated currents on its own. However, in the presence of 5-hydroxyindole the effect of 5-HT in the same cells was significantly altered. Peak current amplitude was increased and desensitization of the 5-HT3 receptor was slowed down compared to cells solely infused with 5-HT. The effects of 5-hydroxyindole take place rapidly and are quickly reversed on washing with an external solution. Similar results can be achieved when infusing cells with other 5-HT receptor agonists. 5-Hydroxyindole enhances the peak amplitude of inward currents induced by infusion with the various 5-HT3 receptor agonists by 30-94% and slows down desensitization 2.5 – 5 fold. 5-Hydroxyindole can be used as a tool to selectively modify the desensitization of the 5-HT3 receptor2.
5-Hydroxyindole (#H-115) is a highly pure, synthetic, and biologically active compound.