TITLE:
Neural Activation by Milnacipran and Memory Extinction
AUTHORS:
Hisahito Ishida, Masaaki Iwata, Yukihiko Shirayama, Katsumasa Muneoka
KEYWORDS:
Milnacipran; Passive Avoidance Task; Prefrontal Cortex; Nucleus Accumbens; Hippocampus; Septum
JOURNAL NAME:
Journal of Behavioral and Brain Science,
Vol.2 No.2,
May
30,
2012
ABSTRACT: Background: Among neurotransmitter influencing memory formation, the noradrenergic system has been recognized as an important system. Memory formation involves various regions including the prefrontal cortex, hippocampus, amygdala and septum. Method: We investigated the effects of milnacipran on passive avoidance task and evaluated Fos counting in the prefrontal cortex, hippocampus, septum, amygdala and nucleus accumbens. Results: The milnacipran-treated rats (20 mg/kg, 4 days) showed a significant decrease in the number of Fos-immunoreactive cells in the infralimbic portion of prefrontal cortex, the shell portion of nucleus accumbens and the CA1 region of hippocampus, but a significant increase in the Fos counts in the lateral septum with no changes in the Fos counts in the striatum and amygdala. The milnacipran-treated rats showed amelioration in memory extinction (although not statistically significant), but not in memory acquisition and consolidation in the passive avoidance test. Conclusion: The differential activation of the brain regions might be possible sites for ameliorating memory extinction as well as antidepressant effects.