CHANGES IN MUSCARINIC ACETYLCHOLINE RECEPTORS OF MICE BY CHRONIC ADMINISTRATIONS OF DIISOPROPYLFLUOROPHOSPHATE AND PAPAVERINE

Chronic administration of diisopropylflourophosphate (DFP) to mice induced decrease in maximal contraction and increase in the ED50 of ileum to the muscarinic agonist oxotremorine. These changes were accompanied by decrease in muscarinic receptors. Papaverine prevented both the changes in contraction and the decrease in muscarinic receptors by DFP. The quantitative relationship between the decrease in receptors and contraction is discussed on the basis of the hypothesis of spare receptors. © 1979.