Chronic neonatal NMDA blockade results in long-term cholinergic increase in the rat spinal cord.

Rat pups were treated daily with increasing doses of the competitive N-methyl-D-aspartate (NMDA) antagonist CGP 39551 from postnatal day 1 to 22. Normal rats, as well as rats kept undernourished to the same extent as CGP 39551-treated animals were raised in parallel. The neonatal treatment resulted in significant increase of choline acetyltransferase (+14%) in the adult spinal cord. High affinity glutamate uptake was increased to a similar magnitude in treated rats, but the same effect was also noticed for neonatally undernourished rats. No alteration of other neurochemical markers was observed. The present results add new evidence to a developmental role mediated by NMDA receptors and extend to the spinal cord the value of models of chronic neonatal block of this receptor.