Effect of Triiodothryonine on the Muscarinic Receptors and Acetylcholinesterase Activity of Developing Rat Brain

The effect of triiodothyronine was investigated on the developing muscarinic system in rat cerebral cortex. Triiodothyronine was administered from birth to day 30. In the synaptosomal membrane fraction of the cerebral cortex, acethylcholinesterase activity and the binding of the muscarinic ligand 3H-quinuclydinylbenzylate increased significantly as compared to the control. An analysis of the binding curve based on Hill plots suggested a positive cooperativity of receptors of the membrane samples obtained from both hormone treated and control animals. The results obtained are in accordance with morphological, biochemical and clinical data on the thyroid hormone effect on central nervous system maturation.