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

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