Differential patterns of extracellular signal-regulated kinase-1 and -2 phosphorylation in rat limbic brain regions after short-term and long-term inhibitory avoidance learning.
Activation of the extracellular signal-regulated kinase-1 and -2 has been shown to be required for neural plasticity and memory. Previous pharmacological studies have demonstrated that inhibition of extracellular signal-regulated kinase-1 and -2 blocks inhibitory avoidance retention. The aim of the present study was to investigate the different neural substrates underlying short- and long-term inhibitory avoidance learning and memory in rats using phosphorylated extracellular signal-regulated kinase-1 and -2 labeling as an index of plasticity. Short- and long-term retention tests were given 10 min or 24 h after inhibitory avoidance training. A significant elevation in the number of phosphorylated extracellular signal-regulated kinase-1 and -2-immunoreactive neurons was observed in area 1 of anterior cingulate cortex, the secondary motor cortex, lateral orbital cortex, claustrum, and the medial amygdala nucleus after the short-term inhibitory avoidance test. After the long-term retention test, phosphorylated extracellular signal-regulated kinase-1 and -2-immunoreactive neurons were localized in area 1 of anterior cingulate cortex, prelimbic cortex, and the central nucleus of amygdala. This suggests that phosphorylated extracellular signal-regulated kinase-1 and -2-immunoreactivity may reveal different brain regions involved in the storage of short- and long-term aversive memories.
Chai
S-C
SC
Department of Psychology, Chung Shan Medical University, Taichung, Taiwan.
Holahan
M R
MR
Shyu
B-C
BC
Wang
C-C
CC
D000818:Animals; D001362:Avoidance Learning / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D004597:Electroshock; D008032:Limbic System / Q000502:physiology*; D008568:Memory / Q000502:physiology; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D023421:Models, Animal; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011930:Reaction Time; D013997:Time Factors
D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3