| Cholinergic neurons utilize choline for synthesis of membrane phosphatidylcholine (PC) and for synthesis of the neurotransmitter acetylcholine (Ach). Studies in the first half of this thesis examined the mechanisms regulating the distribution of choline between PC and Ach synthesis in rat sympathetic neurons induced to become cholinergic by retinoic acid treatment. Upon cholinergic differentiation, choline acetyltransferase activity was increased resulting in greater Ach synthesis, and the activity of choline kinase, which synthesizes phosphocholine, the first intermediate in PC synthesis, was decreased. Overall PC synthesis was unaffected by the decrease in choline kinase activity. Ach is thought to be synthesized predominantly within axon terminals from extracellular choline taken up by a specialized choline transporter. ;In the second part of this thesis, the role of glycosphingolipids (GSLs) in axonal growth was examined. The effect of two inhibitors of sphingolipid synthesis, fumonisin B... |
