Anticonvulsant and antiepileptogenic actions of MK-801 in the kindling and electroshock models.

The actions of MK-801, a noncompetitive antagonist at the N-methyl-d-aspartate subtype of excitatory amino acid receptor, were investigated on the development of kindling and on seizures in the electroshock and kindling models. The drug MK-801 potently and effectively suppressed the tonic hindlimb extension component of electroshock-induced seizures; it also suppressed both the electrophysiological and behavioral manifestations of the development of kindling. In contrast to its effects on electroshock-induced seizures and the development of kindling, MK-801 only partly reduced the duration of seizures in fully kindled animals and did not elevate the threshold for afterdischarge despite the use of a large dose, associated with profound untoward behavioral effects. Together with previous findings, these results support the idea that noncompetitive blockade of NMDA receptors markedly inhibits the development of kindling. The diminished effectiveness of MK-801 against kindled seizures suggests that MK-801 will not be a clinically-useful anticonvulsant against complex partial seizures.