Cellular localization of GABA and GABAB receptor subunit proteins during spermiogenesis in rat testis
Cellular localization of GABA and GABAB receptor subunit proteins during spermiogenesis in rat testis
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DOI：
10.2164/jandrol.04185
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发表时间：
2005-07-01
影响因子：
--
通讯作者：
Watanabe, M
中科院分区：
文献类型：
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作者：
Kanbara, K;Okamoto, K;Watanabe, M
GABA能系统是中枢神经系统的主要抑制调节因子，也可能在外周非神经组织和细胞中发挥重要作用。最近的研究表明，GABA受体在睾丸和精子中都有表达。为了了解GABA能系统在精子发生中的作用，我们用免疫细胞化学方法检测了GABA和GABA(B)受体亚基在大鼠精子中的细胞定位。在高尔基期和帽期精子细胞顶体颗粒周围检测到GABA免疫反应阳性。高尔基期精子细胞顶体囊泡内可见GABA(B(1))免疫反应阳性，帽期精子细胞顶体囊泡内GABA(B(1))免疫反应扩展至覆盖核膜的整个顶体区域。随着精子的成熟，反应性水平逐渐降低。相反，GABA(B(2))免疫反应在高尔基体期没有在精子中观察到，但在帽状期在赤道区检测到。在精子释放过程中，GABA免疫反应和GABA(B(2))免疫反应均转移到残存细胞质。电子显微镜免疫细胞化学显示，帽状期GABA和GABA(B(1))分布于整个顶体小泡内，但不分布在顶体颗粒内。GABA(B(2))免疫反应阳性细胞位于顶体内侧与核膜之间的狭小间隙，仅局限于精子细胞头部赤道区。这些结果表明，GABA能系统可能参与精子发生的调节。
The GABAergic system, a major inhibitory regulator in the central nervous system, may also play important roles in peripheral nonneuronal tissues and cells. Recent studies showed that GABA, receptor is expressed in testis and sperm. To understand the role of the GABAergic system in spermiogenesis, we examined cellular localization of GABA and GABA(B) receptor subunits in rat spermatics by immunocytochemistry. Immunoreactivity for GABA was detected around acrosomal granules of spermatids during the Golgi and cap phases. GABA(B(1)) immunoreactivity was observed in the acrosomal vesicle of spermatids in Golgi phase, and during cap phase, this reactivity expanded to the entire region of the acrosome covering the nuclear membrane. The level of reactivity decreased gradually with maturation of spermatics. In contrast, GABA(B(2)) immunoreactivity was not observed in spermatics during Golgi phase but was detected in the equatorial region during cap phase. Both GABA immunoreactivity and GABA(B(2)) immunoreactivity were transferred to the residual cytoplasm during the release of spermatozoa. Electron microscopic immunocytochemistry revealed that, during cap phase, GABA and GABA(B(1)) were distributed within the whole acrosomal vesicle but not in the acrosomal granule. GABA(B(2)) immunoreactivity was observed in the narrow space between the inner acrosomal and nuclear membrane and was limited to the equatorial region of the spermatid head. These results indicate that the GABAergic system might be involved in regulation of spermiogenesis.