OP/BMP morphogen is combined with GDNF/NGF neurotrophic factors in promoting the survival or growth, or inhibiting the death or degeneration, of mammalian cells, particularly neural cells, which express OP/BMP-activated serine/threonine kinase receptors and GDNF/NGF-activated tyrosine kinase receptors. Also discosed are methods for the treatment of such cells, including treatments for mammals afflicted with, or at imminent risk of, damage or injury to, such cells, as well as new pharmaceutical preparations for such treatments.