| Autor: |
Mezler, Mario, Fleischer, Jörg, Conzelmann, Sidonie, Korchi, Ahmed, Widmayer, Patricia, Breer, Heinz, Boekhoff, Ingrid |
| Zdroj: |
The Journal of Comparative Neurology; October 2001, Vol. 439 Issue: 4 p400-410, 11p |
| Abstrakt: |
Attempts to identify the Gα subtypes in the two compartments of the olfactory system from Xenopus, which are supposed to be specialized for detecting aquatic and volatile odorous compounds, revealed that a Gαo1subtype is characteristic for the “water nose,” the lateral diverticulum, whereas a novel Gαssubtype predominates in the “air nose,” the medial diverticulum. The newly identified Gαs‐type is more closely related to Gαolfof rat and human than to the known Gαs‐isoform of Xenopus; it is therefore considered the first identified nonmammalian Gαolfsubtype. Sequence comparison of Gαolffrom amphibia and mammals revealed a particular conservation within the α‐helical domains, which are supposed to control the GDP/GTP‐exchange rate. The selective expression of different Gα subtypes in the two anatomically separated and functionally specialized nasal compartments parallels the expression of distinct classes of olfactory receptors. Moreover, biochemical analysis revealed that stimulation with appropriate odorous compounds elicits the formation of inositol trisphosphate in the lateral diverticulum. In contrast, cyclic adenosine monophosphate signals were induced in the medial diverticulum, and this response appears to be mediated by the novel Gαolfsubtype. The data indicate that olfactory sensory neurons in each of the nasal cavities are equipped not only with defined sets of receptor types but also with a distinct molecular machinery for the chemo‐electrical transduction process. J. Comp. Neurol. 439:400–410, 2001. © 2001 Wiley‐Liss, Inc. |
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