Chemosensory neurons of the vomeronasal organ (VNO) are supposed to detect pheromones controlling social and reproductive behavior in most terrestrial vertebrates. Recent studies indicate that pheromone signaling in VNO neurons is mediated via phospholipase C (PLC) activation generating the two second messengers inositol-1,4,5-trisphosphate (IP3) and diacylglycerol (DAG). Since G alpha(i) and G alpha(o) predominantly expressed in VNO neurons are usually not involved in activating PLC, it was explored if PLC activation may be mediated by G beta gamma subunits. It was found that a scavenger for beta gamma dimers reduced the urine-induced IP3 formation in VNO preparations in a dose-dependent manner indicating a role for G beta gamma complexes. Towards an identification of the relevant G beta and G gamma subunit(s), PCR approaches as well as immunohistochemical experiments were performed. It was found that out of the five known G beta subtypes, only G beta2 was expressed in both G alpha(i) as well as G alpha(o) neurons. Experimental approaches focusing on the spatial expression profile of identified G gamma subtypes revealed that G gamma8-positive neurons are preferentially localized to the basal region of the vomeronasal epithelium, whereas G gamma2-reactive cells are restricted to the apical G alpha(i)-positive layer of the sensory epithelium. As IP3 formation induced upon stimulation with volatile urinary compounds was selectively blocked by G gamma2-specific antibodies whereas second messenger formation elicited upon stimulation with alpha2u globulin was inhibited by antibodies recognizing G gamma8, it is conceivable that PLC activation in the two populations of chemosensory VNO neurons is mediated by different G beta gamma complexes.

中文翻译：

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选择性G蛋白βγ亚基组合物介导犁鼻器器官中的磷脂酶C活化。

犁鼻器器官（VNO）的化学感觉神经元被认为可以检测控制大多数陆生脊椎动物中社交和生殖行为的信息素。最近的研究表明，VNO神经元中的信息素信号传导是通过磷脂酶C（PLC）激活介导的，产生了两个第二信使肌醇-1,4,5-三磷酸（IP3）和二酰基甘油（DAG）。由于主要在VNO神经元中表达的G alpha（i）和G alpha（o）通常不参与激活PLC，因此探讨了PLC激活是否可以由G betaγ亚基介导。发现β-γ二聚体的清除剂以剂量依赖性方式减少了VNO制剂中尿诱导的IP3的形成，表明其对Gβ-γ复合物的作用。为了确定相关的Gβ和Gγ亚基，进行了PCR方法以及免疫组织化学实验。发现在五个已知的G beta亚型中，只有G beta2在G alpha（i）和G alpha（o）神经元中表达。着眼于已确定的G gamma亚型的空间表达谱的实验方法表明，G gamma8阳性神经元优先定位于犁鼻上皮的基底区域，而G gamma2反应性细胞仅限于顶端G alpha（i）阳性感觉上皮层。由于Gγ2特异性抗体选择性地抑制了由挥发性尿化合物刺激诱导的IP3的形成，而α2u球蛋白刺激引起的第二信使形成被识别Gγ8的抗体抑制了，