The proposed research will study the regulation of cellular function using the neuroblastoma x glioma hybrid cell, NG108-15, as a model system. The biochemical parameters to be studied will include receptor binding activities, membrane-associated enzyme activities, neurotransmitter uptake processes and neurotransmitter releasing systems. The first part of the study will examine the regulation of these biochemical systems during differentiation induced by dibutyryl cAMP and other chemicals, and also during long-term exposure to neurotransmitters and drugs. In the second part of the research, the role of membrane lipid composition in the normal functioning of the cells and in their adaptive responses to environmental changes (i.e. dibutyryl cAMP, drugs, neurotransmitters) will be studied using membrane lipid modification techniques with intact cells. The effects of altering the acyl chain composition on differentiation, the biochemical parameters described above and also the electrical properties of the cells will be determined. By studying many different regulatory events in a single homogeneous cell population, one will hopefully gain insights into the mechanisms by which cellular function is regulated.