Editors' ChoiceNeurobiology

Follow the Endothelin

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Science Signaling  15 Apr 2008:
Vol. 1, Issue 15, pp. ec130
DOI: 10.1126/stke.115ec130

The neurons of the sympathetic nervous system have distinct properties that allow them to regulate a particular end organ. Various models have been proposed to explain how such precise wiring of neurons to their synaptic targets might come about during development. The neurons might grow in a relatively random manner and then adopt appropriate characteristics after interacting with their target tissue, or there might be molecular markers that guide particular neurons to the right target. Makita et al. provide new evidence in favor of the latter scheme for a set of neurons of the superior cervical ganglia (SCG) that follow along the external carotid artery to reach their salivary gland targets. The authors examined mRNA from external carotid artery in microarray analysis to search for expression of transcripts that might encode guidance molecules. They found specific expression of mRNA encoding endothelin-converting enzyme (which converts precursors of endothelin into the active form). Endothelins were also expressed in the arteries, and endothelin receptors were present on a subset of the SCG neurons. In vitro, endothelin 3 promoted outgrowth of explanted SCG neurons. In vivo, in mice lacking expression of endothelin receptor A, the SCG axons were no longer extended along the external carotid arteries. The authors propose that smooth muscle cells of the external carotid artery may release endothelin, a neuropeptide better known for its vasoconstriction activity, which acts as a growth factor for axons of the SCG, guiding them to their salivary gland targets.

T. Makita, H. M. Sucov, C. E. Gariepy, M. Yanagisawa, D. D. Ginty, Endothelins are vascular-derived axonal guidance cues for developing sympathetic neurons. Nature 452, 759-763 (2008). [PubMed]

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