5-HT3 receptor-mediated membrane currents were recorded from voltage-clamped clonal N1E-115 neuroblastoma cells. The inward current response to ionophoretically applied serotonin (5-HT) was reversibly antagonised by the 5-HT3 receptor antagonists GR 38032F and metoclopramide with IC50 values of 0.2 nM and 14 nM, respectively. Low concentrations of (+)-tubocurarine ((+)-Tc) also blocked the response to 5-HT (IC50 = 0.8 nM), but other nicotinic cholinoceptor antagonists (gallamine, vecuronium and trimetaphan) were ineffective when applied at a relatively high concentration (1 μM). Blockade by (+)-Tc was neither voltage- nor use-dependent, suggesting that (+)-Tc does not block 5-HT-activated ion channels in N1E-115 cells.
- GR 38032F
- N1E-115 neuroblastoma cell
- Nicotinic receptor antagonist
- Serotonin (5-HT) receptor
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