ALGINATE IMMOBILIZED MAMMALIAN NEURONS - A POTENTIAL TOOL TO ISOLATE NEW NEURONAL LIGANDS

We developped improved immobilization conditions which permitted (i) to immobilize neuroblastoma cells (N18) in calcium-alginate gel beads, (ii) to test the function of ionic channels using patch-clamp electrophysiological techniques and (iii) to quantitatively analyze ligand interactions with voltage-dependent sodium channels in neurons inside the beads. These results qualify this immobilization technique for the isolation and/or purification of ligands specific for neuronal cells. WHY IMMOBILIZE NEURONAL CELLS ? Immobilization techniques have been adapted to different types of mammalian cells and have led to the production of important molecules such as, for example, erythropoietin or monoclonal antibodies (Mosbach, 1988). It is now well documented that the enormous variety of phenotypic characteristics found in the nervous system require a large repertoire of diffusible factors involved in such differentiation steps (Jessell & Melton, 1992 ; Patterson, 1992).