Corticosterone treatment counteracts lesions induced by neonatal treatment with monosodium glutamate in the mediobasal hypothalamus of the male rat

The effects of glucocorticoids on monosodium glutamate-induced neurotoxicity in the neonatal basal hypothalamus were studied by means of semiquantitative immunocytochemistry for tyrosine hydroxylase, growth hormone releasing factor and luteinizing hormone releasing hormone. Neonatal monosodium glutamate treatment induced a marked decrease in tyrosine hydroxylase immunoreactive neurons in the arcuate nucleus and growth hormone releasing factor immunoreactive nerve terminals in the median eminence. These effects were significantly antagonized by the coadministration of corticosterone. Corticosterone alone had no effect on the parameters studied. No significant change in luteinizing hormone releasing hormone immunoreactivity in the median eminence was detected after any treatment. These results demonstrate that corticosterone, possibly acting via type II corticosterone receptors which are highly enriched in the arcuate neurons, can exert a protective action on glutamate-induced neurotoxicity.