IN-VIVO STIMULATION-INDUCED RELEASE OF MANGANESE IN RAT AMYGDALA

The role of manganese ions in neural functions is poorly understood be cause of the low level of manganese in the brain. An excess of this io n is associated with neurological disorders such as extrapyramidal sym ptoms. We demonstrated that manganese may be taken up by piriform neur ons (tertiary olfactory neurons) after release from the terminals of s econdary olfactory neurons, in which Mn-54 taken up by the soma may be anterogradely transported [A. Takeda, Y. Kodama, S. Ishiwatari, S. Ok ada, Manganese transport in the neural circuit of Rat CNS, Brain Res. Bull. (45) (1998) 149-152]. Here we demonstrate for the first time tha t Mn-54 previously taken up into the amygdala is released with neurotr ansmitters 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 neura l signalling processes. (C) 1998 Elsevier Science B.V. All rights rese rved.