[Effects of hypoxia on the brain cholinergic system in the rat].

Effects of mild hypoxic hypoxia on brain cholinergic system in the rat were investigated with choline acetyltransferase (CAT), acetylcholinesterase (AChE) and muscarinic acetylcholine receptor (MR) as indicators of cholinergic system. Hypoxic exposure of 10% oxygen concentration was undertaken for one week. The activity of CAT and AChE was reduced, while MR increased. CAT is known as the specific enzyme of cholinergic neuron, but AChE is contained also in postsynaptic neuron of the cholinergic neuron. Reduction in the activity of both enzymes may mean reduction in the activity of cholinergic system. MR is contained in postsynaptic membrane. The increase in MR may indicate recovery from agonist-dependent desensitized receptor.