interactions than before interactions, but there were significantly more AR2IRs after interactions than before interactions in the mandarin vo

50 (2) :165-175, 2004 A cta Zoologica S inica 3 33, 710062, ( Microtus m andarinus) (n = 15) ( M. f ostis), ( ER ) (AR) 2 h, 1 h, 1 h, 1 h, 2 h,,, ER ( ER 2IRs),, AR (AR2IRs), ER 2IRs 2 h, ER 2IRs, AR2IRs ; ER 2IRs AR2IRs, ER 2IRs, AR2IRs : ; ER AR, [ 50 (2) : 165-175, 2004 ] ( ER ) (AR) The relationship bet ween social behavior and the expression of estrogen receptor and androgen receptor in olfactory2related bra in regions of the male mandarin vole Microt us mandarinus and reed vole M. f ostis 3 HE Feng2Qin, TAI Fa2Dao 33, ZHAN G Yu2Hui, AN Shu2Cheng College of Life Science, Shaanxi Normal University, Xi an 710062, China Abstract In order to investigate the neurobiological mechanism of the social behavior difference in adult male mandarin voles Microtus m andarinus and reed voles M. f ostis, the behavior focal sampling method and immunohistochemistry method were used to investigate differences in intraspecies male2male interactions and the expressions of estrogen receptor ( ER ) and androgen receptor (AR) between two species, respectively. During the two2hour interaction of male individuals, mandarin voles spent significantly more time on aggressive and defensive behavior to homosexual invaders in the first one hour than in the last hour, whereas the reed voles did not have significantly behavioral difference between the first and last hour. During the whole two2hour interaction of male individuals, mandarin voles spent significantly more time engaged in aggressive and defensive behaviors to homosexual invaders and less time on the nonsocial behaviors than the reed voles. Before the two2hour interaction of male individuals, we found obviously fewer and lighter2stained ER im2 munoreactive neurons ( ER 2IRs) in both main olfactory bulb system project regions and vomeronasal system project re2 gions in the mandarin voles than in the reed voles, but no significant difference in numbers of AR immunoreactive neurons (AR2IRs) between the two species through the examining of immunoreactive neurons. Moreover, there were significantly fewer AR2IRs than ER 2IRs in two species of vole before the two2hour interactions. There were significantly fewer ER2 IRs in both the main olfactory bulb project regions and the vomeronasal system project regions in the mandarin voles after 2003209207, 2003212213 3 (No. 30200026) [ This research was funded by National Natural Science Foun2 dation of China (No. 30200026) and Key Project of Ministry of Education Peoples Republic of China ] 33 (Corresponding author). ν 2004 Acta Zoologica Sinica E2mail : taifadao @snnu. edu. cn

66 1 50 interactions than before interactions, but there were significantly more AR2IRs after interactions than before interactions in the mandarin voles. Differences in both numbers of ER 2IRs and AR2IRs between before and after interactions in the reed voles were not significant. There were greatly significantly more ER 2IRs neurons in reed voles than in mandarin voles which had gone through interactions and there were significantly fewer AR2IRs in the reed voles than in the man2 darin voles which had gone through interactions. The results indicate that mandarin voles and reed voles had different so2 cial behaviors in social interactions. The results suggest that the decrease of ER 2IRs and increase of AR2IRs might affect social recognition and aggressive behavior, and this might explain differences in social behaviors between the two vole species [ Acta Zoologica Sinica 50 (2) : 165-175, 2004 ]. Key words Mandarin voles, Microtus m andarinus, Reed voles, M. f ostis, Main olfactory bulb system, Vomeronasal system, Estrogen receptor ( ER ), Androgen receptor (AR), ( Summers et al., (, 2001b), 1997),,,, ( Gilles et al., (Wang et al., 1997) 1994 ; Buijs et al., 1978 ; Tribollet et al., 1988) ( M icrot us m andarinus) (, 2001b), : ( M. f ostis) (, 2001a), (Murphy, 1980) (Lepri et al., 1985) (, 2003),, ; ( Wysocki (Lawrence et al., 1991), et al., 1982),, (, 2002 ; Wysocki et al., 1983) ER AR,,, ( Gilles et al., 1994) (Miyachi, 1999) (Ogawa et al., 1999, 2000), 111, 15, 30-36 g,,, 15,, 60-74 g,, ( Estrogen receptor, ER ), 18-20 12L 12D, (Androgen receptor, AR) (, 1999),,,, 112, (No2,, mura et al., 2002), ;,, (80 (Mc Ginnis et al., 2002), ER AR, 30 min,, 1 cm 40 cm 40 cm ),,,, THE OBSERV ER ( HOLLAND)

2 : 167 2 h 1 h, ( 1 h, ), 1 h SPSS 5 1 h, 113 2 h, 2 h, (40 mg/ kg),, 011 mol PBS 150 ml,,, 4 % 300 ml, ( 2) 4 % 3 h (4 ), 212 30 % OCT, 40 mer ( Sc2 8974) AR (Ba0004) Santa cruz, ( ), SABC ( - ) ER, DAB Sigma (: 2) (: 4) 37 15 min, ( 4 72 h, 0101 mol PBS 3, 3 min, SABC 37 30 min, 0101 mol PBS 3, 3 min, DAB 10-30 min 0101 mol PBS,,, ( P < 0105,, 0101 mol PBS ER AR, (: 1,, 114 ( P > 0105), ER ( : 3) (: 5) ER 2IRs AR2IRs, (, : 7) ( P < 0105),, ( < 8) ( 1) (60 60) m 2 213 SPSS1010, AR ER, (Mean S E), AR Mann2Whitney U test P < 0105 (: 2) (: 4) ( : 6) 2 211, ( 1) ER, : 6) (: 10) (: 9) ( : 8) ( > 15), ER 8-15) ( 1) 2 h, ER (: 8, P > 0105), ( < 8), ER 1 h, ( P < 0101), ER

68 1 50 1 1 h 1 h a : 1 h b : 1 h c : 1 h d : 1 h 1 : 2 : 3 : 33 : 1 h 1 h (Mann2Whitney2test, P < 0101), 3 : 1 h 1 h ( Mann2 Whitney test, P < 0105) Fig11 Comparison between behaviors of the f irst one hour and the last hours during the interactions of male2male individuals in Microtus mandarinus and Mirotus f ortis a : Behaviors of the first one hour in the mandarin voles. b : Behaviors of the last one hour in the mandarin voles. c : Be2 haviors of the first one hour in the reed voles. d : Behaviors of the last one hour in the reed voles. 1 : Aggressive behavior. 2 : Other social behaviors. 3 : Nonsocial behaviors. 33 : Both aggressive behavior and nonsocial behaviors of the first one hour and the last hours during the interactions in the mandarin voles have greatly significant dif2 ference by Mann2Whitney2test, P < 0101. 3 : Between other social behaviors of the first one hour and the last hours during the interactions in the mandarin voles have significant difference by Mann2Whitney test, P < 0105. 2 2 h a : b : 1 : 2 : 3 : 33 : 2 h (Mann2Whitney test, P < 0101 3 : 2 h (Mann2Whitney U test, P < 0105) Fig12 Behavior during two2hour interactions of male Microtus mandarinus and Mirotus f ortis a : Mandarin voles. b : Reed voles. 1 : Aggressive behavior. 2 : Other social behaviors. 3 : Nonsocial behaviors. 33 : Both aggressive behavior and nonsocial behaviors have greatly significant difference during two hours in two vole species by Mann2Whitney test, P < 0101. 3 : Other social behaviors have significant difference between two vole species by Mann2Whitney test, P < 0105.

2 : 169 1 Table 1 Total number of estrogen receptor immunoreactive neurons ( mean S E) in per standard area in brain region before and after interactions of male2male individuals in Microtus mandarinus and Mirotus f ortis Brain region TU LA PO MDI OPCF ME BST VMH MPO LSD Control ER2 M. mandari nus M. f ortis Experimental ER2 P Control ER2 Experimental ER2 1017 01201 710 01005 01048 3 2410 11040 2310 01980 11000 1011 21010 610 01781 01043 3 2318 21010 2218 11050 01917 1113 11078 712 11500 01035 3 2310 21247 2213 21248 11000 812 01007 510 11007 01047 3 1515 01070 1713 01002 01821 1018 21004 712 11050 01046 3 1918 31001 1812 31041 01931 1310 31005 710 21300 01035 3 1810 21505 1610 11031 01823 1012 21030 711 01002 01048 3 1512 11019 1619 11031 01846 1213 41002 710 01021 01047 3 2813 11025 2615 11785 01912 1110 31031 717 01001 01041 3 2610 21010 2519 11007 11000 1412 21507 714 11500 01035 3 2415 41507 2218 51190 01831 : : TU : LA : PO : MDI : OPCF : ME : BST : VMH : MPO : LSD :, 3 Mann2Whitney ( P < 0105) Control group : Without male exposure. Experimental group : With male exposure. TU : Olfactory tubercle. LA : Lateral amygdaloid nucleus. PO : Piriform cortex. MDI : Mediodorsal thalamic nucleus, intermediate part. OPCF : Orbital prefrontal cortex. ME : Medial amygdaloid nucleus. BST : Bed nucleus of the stria terminalis. VMH : Ventromedial hypothalamic nucleus. MPO : Medial preoptic area. LSD : Lateral septal nucleus, dorsal part. Data is expressed as Mean SD, 3 indicates significant difference between experimental and control groups by Mann2Whitney test, P < 0105. 2 Table 2 Total number of androgen receptor immunoreactive neurons ( mean S E) in per standard area in brain region before and after interactions of male2male individuals in Microtus mandarinus and Mirotus f ortis Brain region TU Control AR M. mandari nus M. f ortis Experimental AR P Control AR Experimental 413 11003 818 11825 01041 3 410 01120 412 01131 01873 LA 010 810 11006 01007 3 010 210 01031 01087 PO MDI OPCF 415 21577 811 11002 01047 3 310 01009 315 01004 11000 410 01001 1010 01030 01027 3 411 01002 210 01030 01067 612 11005 910 01037 01048 3 610 01231 613 01781 11000 ME 010 810 21472 01013 3 010 215 01078 01054 BST VMH MPO LSD 610 11781 1118 11005 01038 3 611 01782 715 01781 01964 710 21000 1210 21005 01043 3 710 21007 810 21040 01892 610 11802 1217 21005 01035 3 510 21001 61080 21532 01653 512 11720 3 1015 11405 01034 3 411 01187 410 01587 11000 : : TU : LA : PO : MDI : OPCF : ME : BST : VMH : MPO : LSD :, 3 Mann2Whitney ( P < 0105) Control group : Without male exposure. Experimental group : With male exposure. TU : Olfactory tubercle. LA : Lateral amygdaloid nucleus. PO : Piriform cortex. MDI : Mediodorsal thalamic nucleus, intermediate part. OPCF : Orbital prefrontal cortex. ME : Medial amygdaloid nucleus. BST : Bed nucleus of the stria terminalis. VMH : Ventromedial hypothalamic nucleus. MPO : Medial preoptic area. LSD : Lateral septal nucleus, dorsal part. Data is expressed as Mean SD, 3 indicates significant difference between experimental and control groups by Mann2Whitney test, P < 0105. AR P P

70 1 50 ( P < 0105), ( Ferguson et al., 2002),, AR ( 2) 2 h, AR, ER ( P > 0105), AR, ( : ( Hlinak, 1993), 5) (: 1) ER,, (: 3) ER, ( : 7) ER ER, ( P < 0105),, ( 8-15) (Fugger et al., 2000) ER ( 2) 3 311 ER AR ER,, ER AR, ER AR AR,, ER AR,, AR (AVP) mrna, ER AR 100, AVP (Brot et al., Jane 1993), AVP and J udwh (1995), ( Ferguson et al., 2002), Winslow et, al. ( 1992) ( M icrot us (Jane and J ud2 ochrogaster) : AVP wh, 1995),, AVP,, ( Kevetter and Winas, 1981),,, 313, 2 h, (Wysocki et al., 1983),,, ER ER (Zhang et al., 2000), 1 h,, ER, Insel et al. (1995) 312 ( M icro2 1 h 1 h, t us montanus), 1 h 1 h,,,, 2 h,,, ( Trivers, 1972 ; Pierce and Dewsbury, : 1991) (Wai and Hoar, 1963),

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2 : 173 71 2 h AR 81 2 h AR PO : MDI : LA : EC : BL P : BST : AC : 3V : VMH : LSD : LV : ME : OT : MPO : CPu : 100 m Explanation of Plates Plate 11 ER immunoreactivity in the lateral amygdaloid nucleus of Microt us mandari nus before interactions of male2male individuals. 21ER immunoreactivity in the lateral amygdaloid of Microt us f ortiss before interactions of male2male individuals. 31ER immunoreactivity in the primary olfactory cortex of Microt us mandari nus after two hours interactions of male2male individuals. 41 ER immunoreactivity in the primary olfactory cortex of Microt us f ortis before interactions of male2male individuals. 51ER immunoreactivity in the medial amygdaloid nucleus nucleus of Microt us mandari nus after two hours interactions of male2male individuals. 61ER immunoreactivity in the medial amygdaloid nucleus nucleus of Microt us f ortis before interactions of male2male individuals. 71ER immunoreactivity in the lateral septal nucleus, dorsal part of Microt us mandari nus after two hours interactions of male2male individuals. 81ER immunoreactivity in the lateral septal nucleus, dorsal part of Microt us f ortiss before interactions of male2male individuals. 91ER immunoreactivity in the medial preoptic area of Microt us f ortiss before interactions of male2male individuals. 101ER immunoreactivity in the bed nucleus of the stria terminalis of Microt us f ortiss before interactions of male2male individuals. Plate 11AR immunoreactivity in the primary olfactory cortex of Microt us mandarinus after two hours interactions of male2male individuals. 21AR immunoreactivity in the primary olfactory cortex of Microt us mandarinus before interactions of male2male individuals. 31 AR immunoreactivity in the mediodorsal thalamic nucleus, intermediate part of Microt us mandarinus after two hours interactions of male2male indi2 viduals. 41AR immunoreactivity in the mediodorsal thalamic nucleus, intermediate part of Microt us mandarinus before interactions of male2male individuals. 51AR immunoreactivity in the lateral amygdaloid nucleus of Microt us mandarinus after two hours interactions of male2male individuals. 61AR immunoreactivity in the bed nucleus of the stria terminalis of Microt us mandarinus before interactions of male2male individuals. 71AR immunoreactivity in the ventromedial hypothalamic nucleus of Microt us mandarinus after two hours interactions of male2male individuals. 81AR immunoreactivity in the lateral septal nucleus, dorsal part of Microt us mandarinus after two hours interactions of male2male individuals. PO : Piriform cortex. MDI : Mediodorsal thalamic nucleus, intermediate part. LA : Lateral amygdaloid nucleus. EC : External capsule. BL P : Posterior division of the basolateral nucleus of the amygdala. BST : Bed nucleus of the stria terminalis. AC : Anterior commissure. 3V : Third ventricle. VMH : Ventromedial hypothalamic nucleus. LSD : Lateral septal nucleus, dorsal part. LV : Lateral ventricle. ME : Medial amygdaloid nucleus. OT : Optic tract. MPO : Medial preoptic area. CPu : Caudate putamen. Scale bar = 100 m.

: HE Feng2Qin et al. : The relationship between social behavior and t he expression of est rogen receptor and androgen receptor in olfactory2related brain regions of the male mandarin vole M icrot us m andarinus and reed vole M. f ostis Plate ( Explanation at the end of the text)

: HE Feng2Qin et al. : The relationship between social behavior and t he expression of est rogen receptor and androgen receptor in olfactory2related brain regions of the male mandarin vole M icrot us m andarinus and reed vole M. f ostis Plate ( Explanation at the end of the text)