Berghard A, Buck L B, Liman E R
Department of Neurobiology, Howard Hughes Medical Institute, Harvard Medical School, Boston, MA 02115, USA.
Proc Natl Acad Sci U S A. 1996 Mar 19;93(6):2365-9. doi: 10.1073/pnas.93.6.2365.
In mammals, olfactory stimuli are detected by sensory neurons at two distinct sites: the olfactory epithelium (OE) of the nasal cavity and the neuroepithelium of the vomeronasal organ (VNO). While the OE can detect volatile chemicals released from numerous sources, the VNO appears to be specialized to detect pheromones that are emitted by other animals and that convey information of behavioral or physiological importance. The mechanisms underlying sensory transduction in the OE have been well studied and a number of components of the transduction cascade have been cloned. Here, we investigated sensory transduction in the VNO by asking whether VNO neurons express molecules that have been implicated in sensory transduction in the OE. Using in situ hybridization and Northern blot analyses, we found that most of the olfactory transduction components examined, including the guanine nucleotide binding protein alpha subunit (G-alpha-olf), adenylyl cyclase type III, and an olfactory cyclic nucleotide-gated (CNG) channel subunit (oCNC1), are not expressed by VNO sensory neurons. In contrast, VNO neurons do express a second olfactory CNG channel subunit (oCNC2). These results indicate that VNO sensory transduction is distinct from that in the OE but raise the possibility that, like OE sensory transduction, sensory transduction in the VNO might involve cyclic nucleotide-gated ion channels.
在哺乳动物中，嗅觉刺激由感觉神经元在两个不同部位检测：鼻腔的嗅觉上皮（OE）和犁鼻器（VNO）的神经上皮。虽然OE能检测从众多来源释放的挥发性化学物质，但VNO似乎专门用于检测其他动物发出的、传达行为或生理重要信息的信息素。OE中感觉转导的潜在机制已得到充分研究，转导级联反应的许多成分已被克隆。在此，我们通过询问VNO神经元是否表达与OE感觉转导有关的分子来研究VNO中的感觉转导。利用原位杂交和Northern印迹分析，我们发现所检测的大多数嗅觉转导成分，包括鸟嘌呤核苷酸结合蛋白α亚基（G-α-olf）、III型腺苷酸环化酶和一种嗅觉环核苷酸门控（CNG）通道亚基（oCNC1），VNO感觉神经元并不表达。相反，VNO神经元确实表达第二种嗅觉CNG通道亚基（oCNC2）。这些结果表明，VNO感觉转导与OE中的不同，但增加了一种可能性，即与OE感觉转导一样，VNO中的感觉转导可能涉及环核苷酸门控离子通道。
