Astroglial cells derived from lateral and medial midbrain sectors differ in their synthesis and secretion of sulfated glycosaminoglycans

Astroglial cells derived from lateral and medial midbrain sectors differ in their abilities to support neuritic growth of midbrain neurons in cocultur es, These different properties of the two types of cells may be related to the composition of their extracellular matrix. We have studied the synthesi s and secretion of sulfated glycosaminoglycans (GAGs) by the two cell types under control conditions and beta -Dxyloside-stimulated conditions, that s timulate the ability to synthesize and release GAGs. We have confirmed that both cell types synthesize and secrete heparan sulfate and chondroitin sul fate. Only slight differences were observed between the proportions of the two GAGs produced by the two types of cells after a 24-h labeling period. H owever, a marked difference was observed between the GAGs produced by the a stroglial cells derived from lateral and medial midbrain sectors, The media l cells, which contain derivatives of the rectal and tegmental midline radi al glia, synthesized and secreted similar to2.3 times more chondroitin sulf ate than lateral cells. The synthesis of heparan sulfate was only slightly modified by the addition of beta -D-xyloside, Overall, these results indica te that astroglial cells derived From the two midbrain sectors have marked differences in their capacity to synthesize chondroitin sulfate, Under in l ive conditions or a long period of in vitro culture, they may produce extra cellular matrix at concentrations which may differentially affect neuritic growth.