Regional CNS levels of acetylcholine and choline during hypoglycemic stupor and recovery.

During insulin stupor in mice, acetylcholine levels in cerebral cortex, cerebellum, brainstem, striatum, and hippocampus were unchanged from control values despite brain glucose concentrations 3-10% of normal, whereas choline levels rose 2.4-3.6-fold in all five CNS regions. Brain acetylcholine and choline levels did not change during recovery following glucose injection. The data suggest that, in hypoglycemic stupor, (1) overall rates of acetylcholine synthesis and degradation remain balanced within each of the CNS regions studied; (2) the biochemical mechanism that elevates brain choline levels is unlikely to be related only to cholinergic synaptic processes; and (3) brain choline levels need not rise for stupor to occur.