The provision of precursors for acetylcholine synthesis

Abstract

This thesis, consisting of three chapters, is a study of the supply of precursors for acetylcholine synthesis.;Chapter 1 examines acetylcholine synthesis in a human neuroblastoma cell line, MC-IXC. Synthesis rates were measured using various radiolabelled precursors for the acetyl moiety. (2-{dollar}\sp{lcub}14{rcub}{dollar}C) Pyruvate was the most effective precursor, yielding rates of synthesis approaching the maximal rates observed in cell homogenates. (U-{dollar}\sp{lcub}14{rcub}{dollar}C) Glucose, 3-hydroxy (3-{dollar}\sp{lcub}14{rcub}{dollar}C) butyrate, (2-{dollar}\sp{lcub}14{rcub}{dollar}) acetate, and (1,5-{dollar}\sp{lcub}14{rcub}{dollar}C) citrate could all serve as precursors, but synthesis rates were much lower using these compounds. The results suggest that the rate of acetylcholine synthesis in MC-IXC cells is limited by the rate of glycolysis.;Chapters 2 and 3 describe an attempt to generate antibodies to the high-affinity choline uptake system (HAChTS) via an anti-idiotypic route. Monoclonal and polyclonal antibodies were generated to the choline uptake inhibitor hemicholinium-3. These antibodies were then used to generate monoclonal and polyclonal anti-idiotypic antibodies. Five of the anti-idiotypic antibodies inhibited the uptake of ({dollar}\sp3{dollar}H) choline into rat brain synaptosomes. Immunocytochemistry using four of the antibodies revealed a staining pattern in hippocampus consistent with the known distribution of cholinergic terminals. The results suggest that these antibodies recognize the HACHTS.