Environmental-enrichment-related variations in behavioral, biochemical, and physiologic responses of Sprague-Dawley and Long Evans rats.
The behavioral, biochemical, and physiologic consequences of 6 wk of environmental enrichment were evaluated in male Long Evans and Sprague-Dawley rats and compared with those of rats in standard single-housing conditions. Standard housing provided little or no social or physical stimulation whereas environmental enrichment comprised group housing for 8 h daily in a 3-story cage equipped with novel stimuli. Dependent measures included performance in the forced swim test, thresholds for brain-stimulation reward, sucrose intake and preference, determination of corticosterone levels before and after brief restraint stress, and rate of weight gain. In forced swimming tests, active behaviors (diving, swimming with struggling, and climbing) tended to dominate over passive behaviors (sinking, floating) in both groups and outbred rat stocks (especially in enriched groups) on the first day. These behaviors were replaced with maintenance behaviors such as grooming and swimming without struggling on the second exposure, with enriched Long Evans rats showing the largest decline in activity. Baseline plasma corticosterone levels were elevated in both rat stocks after 6 wk of enrichment. After restraint stress, hormone levels in enriched animals tended to peak earlier and approach or exceed baseline values more quickly than was observed in the comparable control groups. Rate of body weight gain was greater in enriched Long Evans rats than Sprague-Dawley or control rats. Our observations indicate that stock- and group-associated differences in several indices occur in association with enrichment. The data support the claim that environmental enrichment may render animals more resilient to challenges.
Konkle
Anne T M
AT
Interdisciplinary School of Health Sciences, University of Ottawa, Ottawa, Ontario, Canada. anne.konkle@uottawa.ca
Kentner
Amanda C
AC
Baker
Stephanie L
SL
Stewart
Angela
A
Bielajew
Catherine
C
D000818:Animals; D001522:Behavior, Animal; D003345:Corticosterone / Q000097:blood; D004777:Environment; D006120:Grooming; D006799:Housing, Animal; D007756:Laboratory Animal Science / Q000379:methods; D008297:Male; D051381:Rats; D020318:Rats, Long-Evans; D017207:Rats, Sprague-Dawley; D012201:Reward; D013312:Stress, Physiological; D013550:Swimming; D015430:Weight Gain
D003345:Corticosterone
Physiol Behav. 1997 Aug;62(2):421-6
9251989
PLoS One. 2009;4(1):e4326
19177164
Neurosci Lett. 2006 Aug 14;404(1-2):208-12
16790315
Psychopharmacology (Berl). 2009 Apr;203(3):561-70
19005643
Stress. 2003 Dec;6(4):269-80
14660059
Behav Brain Res. 2000 Jan;107(1-2):21-33
10628727
Behav Pharmacol. 1995 Nov;6(7):682-687
11224370
Neuropsychopharmacology. 2009 Dec;34(13):2767-78
19741591
Physiol Behav. 1980 May;24(5):991-3
7403303
Eur J Neurosci. 2003 Dec;18(12):3367-74
14686910
Horm Behav. 2003 Feb;43(2):281-92
12694638
Eur J Pharmacol. 1978 Feb 15;47(4):379-91
204499
Behav Brain Res. 2002 Nov 15;136(2):583-92
12429420
Brain Res. 2003 Dec 5;992(2):227-38
14625061
Eur J Pharmacol. 1988 Dec 13;158(3):207-12
3253099
Pharmacol Biochem Behav. 1997 Dec;58(4):961-7
9408201
Physiol Behav. 2001 Oct;74(3):313-20
11714494
Behav Brain Res. 2003 Jun 16;142(1-2):151-6
12798276
Pharmacol Biochem Behav. 2002 Aug;73(1):209-24
12076740
Neuropsychobiology. 2005;52(2):90-110
16037678
Neuroscience. 1998 Jun;84(4):1025-39
9578393
Pharmacol Biochem Behav. 2003 Dec;76(3-4):481-6
14643847
Physiol Behav. 1997 Dec 31;63(1):91-100
9402621
Eur J Neurosci. 2004 Sep;20(5):1341-7
15341605
Stress. 1999 Aug;3(1):71-83
19016194
Eur J Pharmacol. 1978 Oct 1;51(3):291-4
568552
J Comp Physiol Psychol. 1978 Dec;92(6):977-98
755062
Behav Pharmacol. 2008 Oct;19(7):706-15
18797247
Physiol Behav. 2004 May;81(3):409-15
15135012
Brain Res. 2007 Jul 16;1158:28-38
17543293
Int J Immunopharmacol. 1998 Dec;20(12):781-9
9877287
Physiol Behav. 1994 Nov;56(5):1041-8
7824569
J Neurosci. 2002 Sep 15;22(18):7840-3
12223535
Behav Brain Res. 2000 Dec 20;117(1-2):137-46
11099767
J Neuroendocrinol. 2004 May;16(5):423-31
15117335
Nature. 1977 Apr 21;266(5604):730-2
559941
Psychopharmacology (Berl). 1994 Aug;115(4):454-62
7871089
Behav Brain Res. 1999 Dec;106(1-2):133-42
10595429
Physiol Behav. 2006 Feb 28;87(2):314-22
16386277
Behav Brain Res. 2006 Nov 1;174(1):181-7
16938358
Neurosci Bull. 2006 May;22(3):144-50
17704842
Ann N Y Acad Sci. 2004 Oct;1025:619-29
15542771
Behav Brain Res. 2006 Apr 25;169(1):57-65
16414129
Epilepsy Behav. 2007 Feb;10(1):26-31
17196883
Neuroendocrinology. 1997 May;65(5):360-8
9158068
Pharmacol Biochem Behav. 2002 Aug;73(1):225-31
12076741
Psychopharmacology (Berl). 2008 Jul;199(1):1-14
18470507
Arch Int Pharmacodyn Ther. 1977 Oct;229(2):327-36
596982
Dev Psychobiol. 1999 Mar;34(2):129-38
10086231
Psychopharmacology (Berl). 1988;94(4):545-50
3131802
Psychoneuroendocrinology. 2009 Oct;34(9):1390-404
19481873
Am J Phys Anthropol. 1997 Sep;104(1):1-21
9331450
Lab Anim (NY). 2008 Sep;37(9):421-8
18719695