Mating behavior induces changes of expression of Fos protein,plasma testosterone and androgen receptors in the accessory olfactory bulb (AOB) of the male mandarin vole Microtus mandarinus

In order to investigate the neuroendocrine mechanism of the mating behavior in the adult male mandarin voles Microtus mandarinus,the radioimmunoassay(RIA)and immunohistochemistry methods were used to investigate the differences in plasma testosterone(T)concentrations and distribution of T immunoreactive neurons(T-IRs),androgen receptor immunoreactive neurons(AR-IRs)and Fos protein immunoreactive neurons(Fos-IRs)in the accessory olfactory bulb(AOB)and the main olfactory bulb(MOB)following exposure to clean hard-wood shavings(control group),soiled bedding(exposure group)or contact with an estrous female(mating group).Results showed that plasma T concentration was significantly higher in the mating group than that in the exposure group,and both the mating group and the exposure group displayed significantly higher plasma T concentration than the control group.T-IRs,AR-IRs and Fos-IRs were investigated with the immunohistochemistry method in granule cell(GC)and mitral cell(MC)of the MOB and the AOB in the three groups.There were significantly more T-IRs,AR-IRs and Fos-IRs in MC and GC of the AOB in the mating group than that in the exposure group or the control group.T-IRs,AR-IRs and Fos-IRs did not show significant differences between the exposure group and the control group.Furthermore,obvious differences in MC and GC of the MOB were not found among the three groups.The results confirm that both changes of T and AR in the AOB might be underlying mating behavior in the adult male mandarin voles.

Comparison of social interaction and neural activation in the main olfactory bulb and the accessory olfactory bulb between Microtus mandarinus and Microtus fortis

To gain insight into the function of AOB and MOB during different social interaction and in different vole species,the behaviors and neural activation of the olfactory bulbs in social interactions of mandarin voles Microtus mandarinus and reed voles Microtus fortis were compared in the present research.Mandarin voles spent significantly more time attacking and sniffing their opponents and sniffing sawdust than reed voles.During same sex encounters,mandarin voles attacked their opponents for a significantly longer time and sniffed its opponent for shorter time compared with male-female interactions.However,no significant behavioral differences were found during encounters of two individual reed voles,regardless of gender composition of the pair.Using c-Fos as an indicator of neural activation,we observed that neural activation was significantly higher in almost all sub-regions of the main olfactory bulb(MOB)and the accessory olfactory bulb(AOB)of mandarin voles compared with reed voles.Numbers of c-Fos-ir neurons in almost all sub-regions of the AOB and the MOB during male-female interactions were also higher than those in interactions of the same sex.Anterior-posterior ratios of Fos-ir neurons in the AOBM(AOBMR)and the AOBG(AOBGR)in male-female interaction were significantly higher than those in interaction of the same sex.The AOBMR of male mandarin voles and reed voles were larger than those of females in male-female interactions.Behavioral patterns are consistent with cellular activity patterns.Consistent level of neural activation in MOB and AOB suggests important roles of both the main olfactory bulb and the accessory olfactory bulb in social interaction in two species.

Co-localization of two-color rAAV2-retro confirms the dispersion characteristics of efferent projections of mitral cells in mouse accessory olfactory bulb

The accessory olfactory bulb(AOB), located at the posterior dorsal aspect of the main olfactory bulb(MOB), is the first brain relay of the accessory olfactory system(AOS), which can parallelly detect and process volatile and nonvolatile social chemosignals and mediate different sexual and social behaviors with the main olfactory system(MOS). However, due to its anatomical location and absence of specific markers, there is a lack of research on the internal and external neural circuits of the AOB. This issue was addressed by singlecolor labeling and fluorescent double labeling using retrograde rAAVs injected into the bed nucleus of the stria terminalis(BST), anterior cortical amygdalar area(ACo), medial amygdaloid nucleus(MeA), and posteromedial cortical amygdaloid area(PMCo) in mice. We demonstrated the effectiveness of this AOB projection neuron labeling method and showed that the mitral cells of the AOB exhibited efferent projection dispersion characteristics similar to those of the MOB. Moreover, there were significant differences in the number of neurons projected to different brain regions, which indicated that each mitral cell in the AOB could project to a different number of neurons in different cortices. These results provide a circuitry basis to help understand the mechanism by which pheromone information is encoded and decoded in the AOS.

菜花原矛头蝮嗅觉系统和犁鼻系统的显微结构

采用组织学方法观察了菜花原矛头蝮(Protobothrops jerdonii)的嗅觉系统和犁鼻系统.结果表明,嗅器位于嗅囊的背侧,犁鼻器则位于嗅器的腹内侧.嗅器的上皮分化为嗅上皮和呼吸上皮,嗅上皮的基底层有Bowman′s腺,呼吸上皮中具有大量的杯状细胞.犁鼻器基底层未发现犁鼻腺.嗅球和副嗅球呈典型的板层构筑结构.推测菜花原矛头蝮嗅器内嗅上皮和呼吸上皮完全分开有利于背侧嗅上皮俘获气味信号,腹侧呼吸上皮参与呼吸作用.虽然菜花原矛头蝮等蛇类的犁鼻器缺少犁鼻腺,但是其眼眶周围的哈氏腺和口腔内的唾液腺可以代偿犁鼻腺机能.

黑线仓鼠、棕色田鼠和大林姬鼠犁鼻系统的显微结构观察

用光镜观察并比较了黑线仓鼠(Cricetulusbarabensis)、棕色田鼠(Microtusmandarinus)和大林姬鼠(Apodemuspeninsulae)犁鼻器和副嗅球的结构.结果表明,黑线仓鼠和棕色田鼠犁鼻器在位置和形态上相似,但这三种鼠犁鼻上皮、犁鼻管腔和犁鼻血管均有较明显的差异.黑线仓鼠和棕色田鼠副嗅球中嗅小球层和颗粒层也存在明显的差异.通过对这两种结构的比较,说明犁鼻系统的结构差异与鼠类的生活环境和繁殖行为有关.

棕色田鼠雄性幼体不同发育期犁鼻器和副嗅球的组织结构

通过对出生后不同发育时期雄性棕色田鼠犁鼻器和副嗅球进行组织学观察 ,探讨棕色田鼠出生后犁鼻器和副嗅球的发育规律。实验以出生后当天 (0日龄 ) ,5日龄 ,15日龄 ,2 5日龄以及成年棕色田鼠为研究对象 ,副嗅球采用Pischinger氏染色法染色 ,犁鼻器用H .E .染色法染色后进行组织学观察。结果显示 ,棕色田鼠出生时 ,犁鼻器和副嗅球就已具有成体的基本结构 ,随着动物个体的发育 ,犁鼻上皮逐渐增厚 ,犁鼻管变长 ,犁鼻上皮中神经元密度增加 ;腺体逐渐增大 ,犁鼻管腔填充物增多 ,犁鼻管背外侧的静脉血管逐日增大 ,管腔周围出现越来越多的血管 ;副嗅球长宽都增加 ,僧帽细胞层和颗粒细胞层逐渐增长 ,各层细胞密度变化稍有不同 ;出生后 15日内 ,僧帽细胞层细胞密度增加 ,15日龄以后又开始降低 ,2 5日龄及成体的僧帽细胞层细胞密度与 5日龄的相似 ;颗粒细胞层细胞密度持续增高。实验结果提示 ,棕色田鼠 5日龄时 ,犁鼻器和副嗅球已具有了完整的结构 ,到 2

甘肃鼢鼠与根田鼠的犁鼻器和副嗅球结构研究

为了探讨地下鼠犁鼻系统与地面鼠的差异及其与地面鼠嗅觉功能相适应的特点,用组织学方法对甘肃鼢鼠(Myospalax cansus)与根田鼠(Microtus oeconomus)的副嗅球和犁鼻器结构并进行了差异性研究。结果表明,2种鼠的犁鼻器均位于鼻腔前端鼻中隔基部两侧,呈管状;甘肃鼢鼠犁鼻上皮厚度、副嗅球颗粒细胞和僧帽细胞带宽比根田鼠发达;甘肃鼢鼠犁鼻器、副嗅球的性二型分化比根田鼠显著。2种鼠各自犁鼻器和副嗅球的形态有一定的对应关系,甘肃鼢鼠犁鼻上皮、副嗅球厚而短;根田鼠犁鼻上皮、副嗅球薄而长。这种对应关系可能与犁鼻器和副嗅球之间存在着神经投射有关。

尿液气味刺激后棕色田鼠主嗅球和副嗅球的神经元活动

本实验利用免疫组织化学方法,以FOS阳性反应作为神经元活动的标志,研究了棕色田鼠在受到同性和异性尿液刺激后主嗅球和副嗅球的神经元活动,表明两大嗅觉系统均有感知社会性化学信号的功能。通过比较棕色田鼠在同性和异性尿液刺激后副嗅球和主嗅球的嗅小球细胞层(GL)、僧帽细胞层(MIT)、颗粒细胞层(GRL)中FOS阳性神经元数量,发现不同性别尿液刺激后棕色田鼠的副嗅球各细胞层FOS阳性神经元数量比对照组明显增加;棕色田鼠受到异性尿液刺激后其副嗅球各细胞层的FOS阳性神经元数量均多于同性尿液刺激组。不同性别尿液刺激后棕色田鼠的主嗅球各细胞层FOS阳性神经元数量相较于对照组有增加或增加显著;异性尿液刺激组主嗅球各细胞层的FOS阳性神经元数量均多于同性尿液刺激组。说明棕色田鼠的副嗅球和主嗅球均参与了通过尿液介导的性别个体的识别。

电生理法对豚鼠副嗅球功能分区的显示

目的 :探讨豚鼠副嗅球 (AOB)是否存在多个功能分区。方法 :在豚鼠副嗅球矢状位切片上 ,将双钨电极插入副嗅球前部或后部的犁鼻神经纤维层 (VNL ) ,以单个方波刺激传入神经纤维 ,用玻璃微电极记录 AOB前部或后部外橄状层 (EPL)细胞外场电位。结果 :电刺激 VNL,可在 EPL 记录到典型的衰减性场电位 ,且后 EPL记录到的场电位的持续时间较前部分明显延长。刺激前 VNL 仅在前 EPL 记录到场电位 ,而刺激后 VNL 只在后EPL 记录到场电位。结论 :豚鼠副嗅球可分为前后两个亚区 ,两区存在解剖学上的差异 ,说明在犁鼻系统中至少存在两个不同的传入 -传出通路。

G蛋白γ13亚单位在发育的嗅上皮和梨鼻中的表达模式研究（英文）

G蛋白亚单位以前被认为在味蕾中特异性的表达,和味导素、苦味受体共表达于味蕾的II型细胞。目前的研究发现,Gγ13(G proteinγ-subunit Gγ13)在小鼠不同发育时期嗅上皮和梨鼻均存在表达,包括胚胎期15.5 d(E15.5)、生后期第0 d(P0)、生后期第5 d(P5)、生后期第10 d(P10)、生后期第21 d(P21)和成年期(>P40)。研究也表明,Gγ13可能是一个成熟嗅神经和梨鼻神经的分子标记物。m RNA原位杂交表明,Gγ13和Gα亚单位Gαolf(Gαolf在成熟嗅神经细胞中表达)的表达模式在嗅上皮是一致的,Gγ13和Gα亚单位Gαi2(Gαi2在成熟梨鼻嗅神经细胞中表达)在梨鼻上皮共定位。Gγ13的分布不同于标记细胞发育的标记物GAP43(growth associated protein 43)在嗅上皮的分布,它的表达也不同于另外一个G蛋白亚单位Gγ8的表达分布。在P21的嗅觉系统,Gγ13蛋白在嗅上皮嗅毛中表达丰富,在梨鼻的嗅毛表达也丰富。在主嗅球,在颗粒细胞带、外网层、僧帽细胞带均发现Gγ13的阳性信号。而且,m RNA原位杂交也显示,Gγ13在僧帽细胞带表达,表明Gγ13可能参与到僧帽细胞向大脑嗅皮质区的信号输送。在副嗅球,在颗粒细胞层发现微弱的阳性信号。总之,目前的研究表明,Gγ13可能参与嗅上皮和梨鼻的嗅分子信号传导过程。

雄激素对小鼠社会行为的影响及其机制

目的研究雄激素对雄鼠社会行为的影响及其机制。方法建立青春期雄性小鼠去势模型。随机分为假手术、去势、去势后丙酸睾酮(TP,0.5、1 mg·kg^-1·d^-1)补充组,给药至实验结束。小鼠成年后,检测其社会行为,分析血清、脑内睾酮水平,石蜡切片观测感受性气味的副嗅球形态,并分析脑内雄激素受体(AR)和参与社会识别记忆的杏仁核脑区加压素(AVP)表达水平。结果 TP补充逆转去势引起的性行为和入侵攻击行为抑制、以及社会识别能力降低,逆转去势诱导的脑内T水平及AR表达水平下降;TP补充增加副嗅球僧帽细胞层细胞密度,并升高杏仁核AVP表达水平。结论雄激素可促进雄鼠的性行为和入侵攻击等社会行为,这可能与其促进脑内AR表达,增加副嗅球僧帽细胞层细胞密度和杏仁核AVP水平从而提高社会识别能力有关。