Serotonin (5-HT) is an inflammatory mediator and involved in pain sensation. Ionotropic 5-HT3 receptors of dorsal root ganglion (DRG) neurons are thought to mediate this effect. However, the role of metabotropic 5-HT receptors remained controversial. In the present study, the contribution of metabotropic 5-HT receptors and their functional interactions with Kv7 channels, tetrodotoxin-resistant (TTX-R) Na+ channels, TRPV1 channels and Ca2+-activated Cl- channels (CaCCs) were investigated. Using the perforated and whole-cell patch clamp technique in voltage and current clamp mode on primary cultures of rat DRG neurons, effects of 5-HT receptor ligands on membrane potential and currents through Kv7 channels, TTX-R Na+ channels, TRPV1 channels and Ca2+-activated Cl- channels were investigated. 5-HT depolarized DRG neurons and increased their excitability. This effect was not altered by the 5-HT3 receptor antagonist tropisetron, but reduced by the 5-HT2 receptor antagonist ritanserin. Moreover, this increased excitation of DRG neurons by 5-HT was inhibited by the TRPV1 antagonist capsazepine and the CaCC blocker CaCC-Inh A01. Furthermore, this 5-HT-induced excitation was inhibited by the 5-HT2C receptor-specific antagonist RS102221 hydrochloride, but not by the 5-HT2A receptor-specific antagonist 4F 4PP oxalate or the 5-HT2B receptor-specific antagonist SB 204741. Currents through Kv7 channels and TTX-R Na+ channels of DRG neurons were not affected by 5-HT. In contrast, 5-HT enhanced currents through TRPV1 channels in DRG neurons. This increase of TRPV1 current was inhibited by the non-selective 5-HT2 receptor antagonist ritanserin as well as the specific antagonists of 5-HT2A (4F 4PP oxalate), 5-HT2B (SB 204741), and 5-HT2C (RS 102221 hydrochloride) receptors. Additionally, 5-HT also induced currents through CaCCs which were inhibited by the CaCC blocker CaCC-Inh A01 and the 5-HT2C receptor-specific antagonist RS 102221 hydrochloride, but not by the 5-HT2A (4F 4PP oxalate) or the 5-HT2B (SB 204741) receptor-specific antagonists. These results show that 5-HT enhances the excitability of DRG neurons via 5-HT2 receptors with a major contribution of 5-HT2C which simultaneously mediates a potentiation of TRPV1 channels and an activation of CaCCs.