Many of the phospholipases and even the receptor for inositol 1,4,5-trisphosphate have recently been cloned and sequenced and play an important role in neurotransmission. Methods developed in recent years for the study of the enzymes and intermediates involved in the regulation of neuronal signal transduction involving phospholipid turnover are presented in this volume. - Techniques for examining the role of phosphoinositides in signal transduction - Techniques related to protein kinase C - Analysis of inositol phosphates - Techniques to analyze phospholipid turnover in the brain