Identification of a 12.5-kD Protein From Caudate-Putamen Nucleus as a Dopaminergic Neuronotrophic Factor

The effect of the extract from caudate-putamen nucleus of newborn rats(CPe)on the dopaminergic(DA)neurons has been studied.An MTT colorimetric microassay measuring optical densities for the growth of DA neuron cultures reveals a significant increase in growth for cultures with CPe as com- pared to those without CPe(p<0.05).Rhodamine retrograde-prelabelled DA neurons were cultured on a Phastgel containing all the electrophoretically separated protein bands from CPe,and able to fish out from it their own trophic factor,a 12.5-kD protein band.The survived neurons at the 12.5-kD protein band were immunostained positive with anti-dopamine antibody.Co-culturing the 12.5 kD-containing gel strip with ex- plants from substantia nigra at a close distance for a week revealed anti-dopamine immunopositive neurites outgrowing from the explants only towards the 12.5-kD gel strip.These results indicate that a 12.5-kD pro- tein from the CPe is capable of maintaining the survival of DA neurons of the substantia nigra and promoting their neurite outgrowth.

The effect of the extract from caudate-putamen nucleus of newborn rats(CPe)on thedopaminergic(DA)neurons has been studied.An MTT colorimetric microassay measuring optical densitiesfor the growth of DA neuron cultures reveals a significant increase in growth for cultures with CPe as com-pared to those without CPe(p&lt;0.05).Rhodamine retrograde-prelabelled DA neurons were cultured on aPhastgel containing all the electrophoretically separated protein bands from CPe,and able to fish out from ittheir own trophic factor,a 12.5-kD protein band.The survived neurons at the 12.5-kD protein band wereimmunostained positive with anti-dopamine antibody.Co-culturing the 12.5 kD-containing gel strip with ex-plants from substantia nigra at a close distance for a week revealed anti-dopamine immunopositive neuritesoutgrowing from the explants only towards the 12.5-kD gel strip.These results indicate that a 12.5-kD pro-tein from the CPe is capable of maintaining the survival of DA neurons of the substantia nigra and promotingtheir neurite outgrowth.