The effect of memantine on various neurobiological processes

Experiments are reported which show that 1,3-dimethyl-5-aminoadamantane (DMAA, D-145, memantine, Memantine) does not influence the binding capacity of a variety of tritiated ligands to rat brain membranes thus suggesting that the drug does not interact with dopamine, opioid, GABA, alpha 1- and alpha 2-adrenergic receptors, but can influence with low potency 5-HT1 receptors. Autoradiographical studies also show that memantine does not interfere with the specific uptake mechanism of various transmitter substances nor is 3H-memantine taken up by any neuronal elements. Memantine at high concentrations was shown to release 3H-monoamines which had previously been taken up by nervous tissue but the release process is independent of calcium ions and is not dose-dependent. The latter effect could be explained by CNS culture studies which show memantine to produce morphological changes in neurones and glia when present at concentrations greater than 50 mumol/l.