N-(3-Aminopropyl)cyclohexylamine is an inhibitor of spermine synthase. N-(3-Aminopropyl)cyclohexylamine is described to specifically deplete rat hepatoma cells of spermidine and spermine levels in culture. N-(3-Aminopropyl)cyclohexylamine is described to antagonize the facilitating effect of spermidine on NMDLA-induced seizures, sμggesting the usefulness of N-(3-Aminopropyl)cyclohexylamine as a tool for studying neuromodulatory polyamines.A competitive inhibitor of spermine and spermidine synthases. N-(3-Aminopropyl)cyclohexylamine is an inhibitor of spermine synthase. N-(3-Aminopropyl)cyclohexylamine is described to specifically deplete rat hepatoma cells of spermidine and spermine levels in culture. N-(3-Aminopropyl)cyclohexylamine is described to antagonize the facilitating effect of spermidine on NMDLA-induced seizures, suggesting the usefulness of N-(3-Aminopropyl)cyclohexylamine as a tool for studying neuromodulatory polyamines. A competitive inhibitor of spermine and spermidine synthases.