Influence of manganese on the release of neurotransmitters in rat striatum.

On the basis of the evidence that manganese may be released along with glutamate into the extracellular space in the hippocampus and amygdala, the release of manganese and its influence in the striatum was examined by using the in vivo microdialysis method in the present study. The release of 54Mn previously taken up by the striatum into the extracellular space was enhanced during stimulation with 100 mM KCl. This enhancement of 54Mn release into the striatal extracellular space was inhibited by addition of 1 micro M tetrodotoxin. When the rat striatum was perfused with artificial CSF containing 200 nM MnCl(2), the levels of GABA in the perfusate were remarkably decreased, while the levels of glutamate, aspartate, and glycine in the perfusate were not appreciably decreased. These results suggest that manganese released into the synaptic cleft in a calcium- and impulse-dependent manner may influence GABA release in the striatum.