Comparison of the Molecular Forms of the Cholinesterases in Tissues of Normal and Dystrophic Chickens

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Abstract
The levels and molecular forms of acetylcholinesterase (AChE, EC 3.1.1.7) and pseudocholinesterase (.psi.ChE, EC 3.1.1.8) were examined in various skeletal muscles, cardiac muscles and neural tissues from normal and dystrophic chickens. The relative amount of the heavy (Hc) form of AChE in mixed-fiber-type twitch muscles varies in proportion to the percentage of glycolytic fast-twitch fibers. Muscles with higher levels of oxidative fibers (i.e., slow-tonic, oxidative-glycolytic fast-twitch or oxidative slow-twitch) have higher proportions of the light (L) form of AChE. The effects of dystrophy on AChE and .psi.ChE are more severe in muscles richer in glycolytic fast-twitch fibers (e.g., pectoral or posterior latissimus dorsi, PLD). There is no alteration of AChE or .psi.ChE in a slow-tonic muscle. In the pectoral or PLD muscles from older dystrophic chickens, the AChE forms revert to a normal distribution while the .psi.ChE pattern remains abnormal. Muscle .psi.ChE is sensitive to collagenase in a similar way as is AChE, thus apparently having a similar tailed structure. Unlike skeletal muscle, cardiac muscle has very high levels of .psi.ChE, present mainly as the L form; AChE is present mainly as the medium form, with smaller amounts of L and Hc. The latter pattern of AChE forms resembles that seen in several neural tissues examined. No alterations in AChE or .psi.ChE were found in cardiac or neural tissues from dystrophic chickens.