Psychoimmunological effects of dioscorea in ovariectomized rats: role of anxiety level.
BACKGROUND
Anxiety levels in rats are correlated with interleukin-2 (IL-2) levels in the brain. The aim of the present study was to investigate the effects of dioscorea (wild yam), a Chinese medicine, on emotional behavior and IL-2 levels in the brain of ovariectomized (OVX) rats.


METHODS
One month after ovariectomy, female Wistar rats were screened in the elevated plus-maze (EPM) test to measure anxiety levels and divided into low anxiety (LA) and high anxiety (HA) groups, which were then given dioscorea (250, 750, or 1500 mg/kg/day) by oral gavage for 27 days and were tested in the EPM on day 23 of administration and in the forced swim test (FST) on days 24 and 25, then 3 days later, the brain was removed and IL-2 levels measured.


RESULTS
Compared to sham-operated rats, anxiety behavior in the EPM was increased in half of the OVX rats. After chronic dioscorea treatment, a decrease in anxiety and IL-2 levels was observed in the HA OVX rats. Despair behavior in the FST was inhibited by the highest dosage of dioscorea.


CONCLUSIONS
These results show that OVX-induced anxiety and changes in neuroimmunological function in the cortex are reversed by dioscorea treatment. Furthermore, individual differences need to be taken into account when psychoneuroimmunological issues are measured and the EPM is a useful tool for determining anxiety levels when examining anxiety-related issues.
Ho
Ying-Jui
YJ
School of Psychology, Chung Shan Medical University, No, 110, Sec, 1, Chien-Kuo N, Rd., Tai-Chung City 402, Taiwan, ROC. yjho@csmu.edu.tw
Wang
Ching-Fu
CF
Hsu
Wen-Yu
WY
Tseng
Ting
T
Hsu
Cheng-Chin
CC
Kao
Mei-Ding
MD
Tsai
Yuan-Feen
YF
J Mol Cell Cardiol. 1999 Aug;31(8):1527-37
10423350
Neuroscience. 1998 Jun;84(3):923-33
9579794
Neurosci Lett. 2000 Jun 23;287(2):117-20
10854726
Arch Gynecol Obstet. 2001 Jan;264(4):199-202
11205708
Arzneimittelforschung. 2001;51(3):238-45
11304940
Biomed Sci Instrum. 2001;37:281-6
11347403
Pharmacol Biochem Behav. 2001 Sep;70(1):85-93
11566145
Calcif Tissue Int. 2001 Aug;69(2):73-7
11683426
Brain Res. 2002 Mar 8;929(2):218-25
11864627
Behav Brain Res. 2002 Oct 17;136(1):1-12
12385785
Am J Chin Med. 2002;30(4):609-16
12568288
Neurosci Lett. 2003 May 8;341(3):205-8
12697284
Biomed Sci Instrum. 2003;39:335-40
12724916
J Nat Prod. 2003 May;66(5):646-50
12762799
Nutrition. 2003 Jul-Aug;19(7-8):646-51
12831952
Nature. 1951 Jul 7;168(4262):28
14852935
Behav Neurosci. 2004 Apr;118(2):306-13
15113256
Brain Res. 2005 May 10;1043(1-2):179-85
15862531
Int Immunopharmacol. 2004 Nov;4(12):1489-97
15351318
Psychother Psychosom. 2004 Sep-Oct;73(5):286-92
15292626
Brain Res Mol Brain Res. 2005 Jun 13;137(1-2):159-65
15950774
Behav Brain Res. 2006 Apr 3;168(2):339-44
16337016
Pharmacol Biochem Behav. 1991 Jun;39(2):373-7
1946578
Psychopharmacology (Berl). 1990;101(4):511-8
2388974
Planta Med. 1990 Jun;56(3):264-7
2392490
J Neurosci Methods. 1985 Aug;14(3):149-67
2864480
Maturitas. 1985 Sep;7(3):193-201
4079819
Nature. 1977 Apr 21;266(5604):730-2
559941
J Dairy Sci. 1968 Mar;51(3):420-7
5638000
J Pharmacol Toxicol Methods. 1993 Jun;29(3):129-38
8103377
Physiol Behav. 1993 Dec;54(6):1119-24
8295951
J Psychiatry Neurosci. 1995 Nov;20(5):364-71
8527423
Life Sci. 1996;59(11):PL147-57
8795709
J Neuroimmunol. 1997 Mar;73(1-2):183-90
9058775
Proc Soc Exp Biol Med. 1998 Mar;217(3):369-78
9492350
Behav Neurosci. 1999 Oct;113(5):1030-41
10571485