Repeated treatment with N-methyl-d-aspartate antagonists in neonatal, but not adult, rats causes long-term deficits of radial-arm maze learning

Sedative and anticonvulsant drugs suppress postnatal neurogenesis

“…Our findings are in agreement with results of other groups who reported impairment in learning and memory tasks after early postnatal treatment with NMDA antagonists 39 or GABA agonists. 40 These data need to be viewed with caution.…”

Latent inhibition in rats neonatally treated chronically with MK-801: Differential effects on conditioned taste aversion and conditioned emotional response

“…More importantly, it also suggests that rats neonatally treated with MK-801 have normal cognitive ability required to learn aversive conditioning or CS-US association in adulthood. Although previous studies reported that neonatal treatment with MK-801 prevented rats from acquiring spatial learning [12][13][14][15][16], there have been no reports that investigated prolonged effects of chronic neonatal treatment with MK-801 on non-spatial learning such as classical and operant conditionings. It was reported in rats that a single treatment with CGP 43487, a competitive NMDA receptor antagonist, at PND 5 impaired freezing response to olfactory and auditory stimuli in fear conditioning on PND 20 [31].…”

“…Second, locomotor activity is also one of the most investigated behavioral items in animals neonatally treated with NMDA receptor antagonists. In many cases, rodents with neonatal NMDA receptor blockade showed hyperactivity in various situations such as open-field and activity box [8,14,[17][18][19], but in some reports there were not significant effects of the neonatal treatment [15,[20][21][22]. Third, pre-pulse inhibition (PPI), a neurological inhibitory phenomenon induced by weaker pre-stimulus just before salient startle stimulus, has been also disturbed in animals neonatally treated with NMDA receptor antagonists [17,21,22] suggesting impairment of ability in sensory gating.…”

Development and characterization of chronic animal models of schizophrenia

“…Therefore, the developing brain is highly susceptible to a chronic, low-dose blockade of NMDA receptors: it causes synaptic weakening and elimination in several brain regions, including the prefrontal cortex and the hippocampus [48][49][50][51][52][53][54]. Thus NMDA receptor antagonists (e.g.…”

“…Some reports suggest motor disturbances after NMDA antagonist treatment too, but the results are inconsistent, and the effect depends on the age of the animals [48,161,194]. Cessation of treatment in adult or juvenile rodents did not cause gross changes in motor activity, while early postnatal treatment was effective in this respect [48,50,130,207]. Beninger's laboratory investigated the effects of subchronic MK-801 treatment and postweaning social isolation on motor activity [86,87,208].…”