DISTINCT ADHESIVE PROPERTIES OF CILIARY AND CHOROID NEURONS FROM THE AVIAN CILIARY GANGLION

The avian ciliary ganglion (CG) contains two populations of neurons: c iliary neurons, which innervate striated muscle, and choroid neurons, which innervate vascular smooth muscle. We used cell size (ciliary cel ls are larger) and somatostatin immunoreactivity( which is restricted to choroid cells) as markers to compare the adhesive properties of the se two neuronal types. Similar numbers of freshly dissociated embryoni c chick ciliary and choroid neurons adhered to laminin (laminin 1) and polylysine, consistent with the fact that each population comprises a bout half of the ganglionic neurons. In contrast, severalfold more cil iary neurons than choroid neurons adhered to a recombinant fragment of a synapse-specific basal lamina protein, s-laminin/laminin beta 2. Mo reover, severalfold more ciliary neurons than choroid neurons adhered to a plastic surface when assayed by the method of Needels et al. in s erum-free medium. Adhesion to s-laminin and plastic appears to be medi ated by different cell surface components, as adhesion to recombinant s-laminin is inhibited by the tripeptide, LRE, and by Ca2+ ions, but n ot by heparin, whereas adhesion to plastic is LRE and Ca2+ insensitive but heparin sensitive. Both adhesive differences are apparent at embr yonic day 8, soon after the ciliary and choroid neurons have begun to form synapses. Thus, two sets of neurons in the CG that send axons thr ough different nerves and innervate different targets also show distin ct adhesive behaviors. (C) 1995 John Wiley & Sons, Inc.