Swim stress differentially affects limbic contents of 2-arachidonoylglycerol and 2-oleoylglycerol. Neuroscience 2012 Mar 01;204:74-82
Date
12/24/2011Pubmed ID
22192839Pubmed Central ID
PMC3288304DOI
10.1016/j.neuroscience.2011.11.065Scopus ID
2-s2.0-84857125720 (requires institutional sign-in at Scopus site) 15 CitationsAbstract
UNLABELLED: Restraint stress exposures evoke progressively larger increases in 2-arachidonoylglycerol (2-AG) in limbic brain regions as the number of repetitions increases. The Porsolt swim test usually involves two swim exposures separated by 24 h, and we asked whether the 2-AG response differed between the first and second exposures.
METHODS: Four groups of male C57/Bl6N mice were studied: control; exposed to a single 6 min swim and killed immediately; exposed to a single 6 min swim and killed 24 h later; and exposed to two swims, separated by 24 h, and killed after the second swim. Outcomes were swim behavior, serum corticosterone, and 2-AG and 2-oleoylglycerol (2-OG) contents in amygdala, hippocampus, and prefrontal cortex.
RESULTS: Mean 2-AG contents were not significantly different among the four treatment groups in any brain region and did not correlate with immobility in either forced swim exposure. However, 2-AG contents in all three brain regions only of the mice exposed to two swims were significantly, positively correlated with serum corticosterone concentrations measured at the same time. 2-OG is present in brain and exhibits a striking regional heterogeneity in control mice. 2-OG concentrations in prefrontal cortex were significantly reduced in the mice killed on the second day compared with the mice killed on the first day. As the target of 2-OG in brain is not known, the significance of these observations await further studies.
CONCLUSIONS: Although prior exposure to swim stress does not alter brain 2-AG contents upon re-exposure, 2-AG concentrations in brain become significantly correlated with the hypothalamic-pituitary-adrenal (HPA) axis response to stress when prior exposure to the stress has occurred. These data suggest that even a single exposure to a short period of intense stress sensitizes the 2-AG response to re-exposure to that situation and are consistent with a role for endocannabinoid signaling in modulating stress responses.
Author List
Roberts CJ, Stuhr KL, Hillard CJAuthors
Cecilia J. Hillard PhD Associate Dean, Center Director, Professor in the Pharmacology and Toxicology department at Medical College of WisconsinChristopher J. Roberts MD, PhD Assistant Professor in the Anesthesiology department at Medical College of Wisconsin
MESH terms used to index this publication - Major topics in bold
AnimalsArachidonic Acids
Corticosterone
Endocannabinoids
Glycerides
Hypothalamo-Hypophyseal System
Limbic System
Male
Mice
Pituitary-Adrenal System
Stress, Physiological
Stress, Psychological
Swimming
