Molecular and electrophysiological changes in the prefrontal cortex-amygdala-dorsal periaqueductal grey pathway during persistent pain state and fear-conditioned analgesia
Date
2011-10Author
Butler, Ryan K.
Finn, David P.
Metadata
Show full item recordUsage
This item's downloads: 412 (view details)
Recommended Citation
Butler RK, Nilsson-Todd L, Cleren Carine, Garcia R, Finn DP (2011). Molecular and electrophysiological changes in the prefrontal cortex-amygdala-dorsal periaqueductal grey pathway during persistent pain state and fear-conditioned analgesia. Physiology and Behavior, 104(5):1075-81.
Published Version
Abstract
Fear-conditioned analgesia (FCA) is the reduction in pain responding which is expressed upon re-exposure to a context previously paired with an aversive stimulus. Projections along the prefrontal cortex (PFC)¿amygdala¿dorsal periaqueductal grey (dPAG) pathway may mediate FCA. However, there is a paucity of studies measuring both molecular and electrophysiological changes in this pathway in rats expressing persistent pain-related behaviour or FCA. Male Lister-hooded rats, with stimulating and recording electrodes implanted in the amygdala and dPAG, respectively, either received or did not receive footshock (0.4 mA) paired with context, followed 23.5 h later by an intraplantar injection of saline or formalin (50 ¿L, 2.5%) into the right hindpaw. Thirty minutes post-formalin/saline, rats were re-exposed to the context for 15 min, during which pain-related behaviours were assessed in addition to evoked field potential recordings in the amygdala¿dPAG pathway. Immediately after the 15-minute trial, PFC tissue was isolated for measurement of total and phosphorylated extracellular-signal regulated kinase (ERK) by western blotting. Formalin-evoked nociceptive behaviour in non-fear-conditioned rats was associated with increased field potential amplitude in the dPAG and increased relative expression of phospho-ERK in the PFC. These effects were abolished in rats expressing FCA. Fear conditioning in non-formalin treated rats was associated with increased phospho-ERK in the PFC but no change in field potential amplitude in the dPAG. Together, these data suggest differential, state-dependent alterations in electrophysiological activity and ERK phosphorylation along the PFC¿amygdala¿dPAG pathway during pain, conditioned fear, and FCA.
Collections
This item is available under the Attribution-NonCommercial-NoDerivs 3.0 Ireland. No item may be reproduced for commercial purposes. Please refer to the publisher's URL where this is made available, or to notes contained in the item itself. Other terms may apply.
The following license files are associated with this item: