In vivo stimulation-induced release of manganese in rat amygdala

The role of manganese ions in neural functions is poorly understood because of the low level of manganese in the brain. An excess of this ion is associated with neurological disorders such as extrapyramidal symptoms. We demonstrated that manganese may be taken up by piriform neurons (tertiary olfactory neurons) after release from the terminals of secondary olfactory neurons, in which 54Mn taken up by the soma may be anterogradely transported [A. Takeda, Y. Kodama, S. Ishiwatari, S. Okada, Manganese transport in the neural circuit of Rat CNS, Brain Res. Bull. (45) (1998) 149-152]. Here we demonstrate for the first time that 54Mn previously taken up into the amygdala is released with neurotransmitters into the extracellular space during stimulation with high K+. The results suggest that the role of manganese ions in the amygdala, and probably in the olfactory system, is dynamically linked to neural signalling processes.