03 Sep 1998

The growing tips, or growth cones, of neurons are confronted with a chemical cacophany of growth-guiding cues. How do they know which ones to heed? In an article appearing in Science (4 September issue), H.-J. Song and colleagues report that they are able to manipulate growth cones into eliciting either attraction or repulsion to each other, depending on the amount of two signalling molecules, cAMP and cGMP, present in the cells. The authors suggest that these signaling molecules may therefore be targets for designing treatments that help regenerate neurons in the central nervous system.—June Kinoshita