Effects of footshocks on anxiety-like behavior and mRNA levels of precursor peptides for corticotropin releasing factor and opioids in the forebrain of the rat.
Corticotropin releasing factor (CRF) and dynorphin are neuropeptides that are associated with the negative emotional states. Experimental evidence indicates that dynorphin neurons located in the nucleus accumbens and CRF neurons in the bed nucleus of the stria terminalis (BST) and the central nucleus of the amygdala (CeA) mediate anxiety-like behaviors immediately after the stressful experience (24-48h). The present study was done to evaluate if changes in the levels of the mRNA for these peptides in the striatum, BST, and CeA were associated with the long-lasting avoidance of novelty, a measure of an anxiety-like state, in a subset of rats exposed to unpredictable and moderately intense footshocks (5×2s of 1.5mA). Shocked rats with enhanced fear to a novel tone 24h after the footshocks (high responders; HR) displayed long-lasting avoidance in the elevated T-maze whereas shocked rats with low levels of acute fear (low responders; LR) had low levels of avoidance similar to nonshocked rats. An increase in the level of proCRF mRNA was detected in the CeA of the HR compared to LR and nonshocked rats but not in other areas of the brain sampled. In contrast, prodynorphin and proenkephalin mRNA levels in the striatum, BST and CeA were not different between HR, LR and nonshocked rats. This study provides evidence that CRF neurons in the CeA may play a role in the anxiety-like state produced in a subset of rats exposed to footshocks.
['Wang|Huiying|H|', 'Li|Sa|S|', 'Kirouac|Gilbert J|GJ|']
D000818:Animals D001007:Anxiety D001362:Avoidance Learning D066274:Central Amygdaloid Nucleus D003342:Corpus Striatum D003346:Corticotropin-Releasing Hormone D004597:Electroshock D004745:Enkephalins D005239:Fear D008297:Male D011498:Protein Precursors D012333:RNA, Messenger D051381:Rats D017207:Rats, Sprague-Dawley D012686:Septal Nuclei
Corticotropin releasing factor Dynorphin Bed nucleus of the stria terminalis Amygdala Striatum Anxiety Enkephalin