The NMDA receptor complex is thought to be altered in kindling, an animal model for complex partial epilepsy. This receptor complex has several modulatory sites including those for glutamate, glycine and polyamines with activation resulting in altered cation channel opening. Two NMDA receptor effectors, ifenprodil and arcaine, were evaluated for effects on the acquisition of electrical kindling of the amygdala. Rats were administered 0, 3.2, 10, 32 and 100 microg of ifenprodil or 0, 32 or 100 microg of arcaine, intracerebroventricularly, 10 min before a daily kindling stimulus. Ifenprodil, at low doses, enhanced kindling acquisition, while the highest dose, 100 microg, inhibited kindling. Arcaine increased the number of trials required to reach fully generalized (stage 5) seizures at the 100 microg dose. Since these agents had mixed actions on kindling development, it is unclear whether these or similar NMDA effectors would be useful in the modulation of complex partial seizures.