The modulatory effect of melatonin on the dopamine-glutamate interaction in the anterior hypothalamus during ageing.

We investigated the effects of melatonin on the dopamine-glutamate interaction in the anterior hypothalamus of young, middle-aged and aged rats. In young rats, under the effects of amphetamine, melatonin produced an inhibition of dopamine release and a significant increase in glutamate and aspartate release. In middle-aged and aged rats, the inhibitory effects of melatonin on amphetamine-evoked dopamine release were maintained, but no effects on glutamate or aspartate release were found. These results suggest that, during ageing, the modulatory effect of melatonin on dopamine release in rat anterior hypothalamus is preserved whereas the dopamine-glutamate interaction is disrupted with age.