DIFFERENTIAL EXPRESSION OF CELL-ADHESION MOLECULES ON TRIGEMINAL CUTANEOUS AND MUSCLE AFFERENTS

Previous work from our laboratory (Woodbury and Scott, 1995) suggested that embryonic cutaneous and muscle afferents might express different surface cell adhesion molecules (CAMs) on their growth cones. To exam ine this possibility directly we measured the relative levels of expre ssion of various adhesion molecules on growth cones of neurons from th e dorsomedial portion of the trigeminal ganglion (DM-TG), which are la rgely cutaneous, and from the trigeminal mesencephalic nucleus (TMN), which are exclusively muscle afferents. Axonin-1, L1, BEN, and N-cadhe rin were expressed more abundantly on DM-TG growth cones, whereas N-CA M was more abundant on TMN neurons. Expression of polysialated N-CAM w as similar on the two populations; addition of NGF and NT-3 appeared t o increase expression of polysialated N-CAM on TMN neurons. Although t he levels of L1 and axonin-1, both of which bind L1, were markedly dif ferent on TMN and DM-TG neurons, these differences were not sufficient to cause dramatic differences in the growth rates of TMN and DM-TG ne urons on L1. (C) 1996 Academic Press, Inc.