NEURITE-PROMOTING ACTIVITY OF COLLAGENS ON EMBRYONIC NEURONS - DECREASED EFFECT AT THE POSTNATAL STAGE

We studied the in vitro neurite outgrowth activity of fibronectin, lam inin, heparan sulfate proteoglycan, type I collagen, type IV collagen, and type VIII collagen in cholinergic neuronal cell lines and primary cultured neurons. All these substances had high neurite promoting act ivity on primary cultured neurons from embryonic mouse brain. However, collagens had no such an effect on primary cultured neurons from post natal brain. When neuronal cell lines were used, collagens and other e xtracellular matrix substances were equally and highly effective on ce lls originated from embryonic brain, but collagens were less effective on cells from postnatal brain. These findings suggest that postnatal neurons lose the neuritic responsiveness to collagens earlier than tha t of other ECM.