Low molecular weight agents support survival of cultured neurons from the central nervous system

Microcultures of dissociated neurons from various central and peripheral neural tissues were used for quantitative analysis and characterization of trophic agents directed to these test neurons. Media conditioned by a variety of central and peripheral glial as well as muscle cell cultures contain trophic activities for central neurons which are distinct from the more traditional protein factors directed to peripheral neurons, by at least two features: (1) they reside with low molecular weight (Mr less than 1000) agents which are resistant to heat, extremes of pH, and various proteolytic and peptidolytic enzymes; and (2) they are necessary for the short-term survival of a variety of rodent and avian central neurons, but they fail by themselves to support survival of peripheral neurons under the same culture conditions.