Corticosterone response to the plus-maze: High correlation with risk assessment in rats and mice

Ethopharmacology Laboratory, School of Psychology, University of Leeds, UK.
Physiology & Behavior (Impact Factor: 3.03). 12/1999; 68(1-2):47-53. DOI: 10.1016/S0031-9384(99)00140-7
Source: PubMed

ABSTRACT Exposure to the elevated plus-maze induces behavioural and physiological effects in rodents consistent with fear/anxiety. Maze-naive animals display high levels of risk assessment towards the open arms, and explore these areas less extensively than other parts of the maze while, immediately following the test, pain latencies, skin conductance levels, and plasma corticosterone titres (CORT) are significantly elevated. Although previous research has suggested a link between the plasma CORT response and open-arm exploration, significant elevations in CORT have also been found with restricted exposure to the closed arms. The present study employed ethological measures in an attempt to further characterise the relationship between behavioural and CORT responses to this widely used animal model of anxiety. Our results confirm that, relative to home-cage controls, 5-min exposure to the plus-maze significantly increases plasma CORT levels in test-naive male Wistar rats and male Swiss-Webster mice. Furthermore, in both species, the CORT response was found to be highly correlated with measures of risk assessment (mice: rs = +0.87; rats: rs = +0.58), but not with measures of open-arm activity (entries, time), general locomotor activity, rearing, or head dipping. Findings are discussed in relation to the functional significance of risk assessment in potentially dangerous situations and the potential involvement of glucocorticoids in this process. All rights reserved.

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    • "(Rodgers et al., 1999 "
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    Stress (Amsterdam, Netherlands) 04/2014; DOI:10.3109/10253890.2014.910762 · 3.46 Impact Factor
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    • "In the field studies, vigilance is commonly defined in terms of searching/scanning activity and is typically measured as the tendency of an animal to scan the environment (i.e., to look around), as opposed to eating, grooming, sleeping, or other nondefensive behaviors (Lima 1987). In laboratory rodent studies, the most commonly used measures of risk assessment behaviors include stretched attend posture (SAP), " flat-back " approach, and protected head-dips/head-outs (Blanchard et al. 1990; Choleris et al. 2001; Cole and Rodgers 1994; Griebel et al. 1997; Rodgers et al. 1999; Roy and Chapillon 2004). The vigilant scanning has also been reported by a number of rodent studies, mostly as a part of " head-out " behavior (Blanchard and Blanchard Choy and Yu contributed equally to this work. "
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