Alterations in Acetylcholine Synthesis and Cyclic Nucleotides in Mild Cerebral Hypoxia

In order to elucidate changes accompanying mild cerebral hypoxia, the synthesis of the neurotransmitter acetylcholine and the concentrations of cyclic AMP and cyclic GMP have been compared to changes in brain lactate in the forebrain of mice made mildly hypoxic. Both histotoxic hypoxia (injection of KCN) and anemic hypoxia (injection of NaNO2) were studied. Acetylcholine synthesis was followed by a double‐label technique using [U‐14C] glucose and [2H4] choline. A 43%, decrease in the synthesis of acetylcholine from [U‐14C]glucose and an 80% increase of the level of cyclic GMP accompanied hypoxia so mild that there were no significant changes in cerebral lactate, or in cyclic AMP (or in AMP: Gibson & Blass, 1976b). Changes in glucose utilization do not account for the decrease in glucose incorporation into acetylcholine. Glucose utilization decreases and then increases with increasing hypoxia, whereas incorporation into acetylcholine decreased with increased hypoxia.