Changes in the Levels and Forms of Cholinesterases in the Blood Plasma of Normal and Dystrophic Chickens

Abstract

Acetylcholinesterase (AChE) and pseudocholinesterase (°ChE) were analysed in the blood plasma of developing chickens, both normal and those with inherited muscular dystrophy. The amounts and the molecular forms of each were examined. °ChE concentration rises in the plasma of normal and dystrophic chicks at the end of embryonic development and is maintained after hatching at a constant, relatively high level, accounting for 90‐95% of total cholinesterase activity in normal plasma. This level is maintained in normal and dystrophic chickens. In embryonic plasma of both normal and dystrophic chicks, on the other hand, the levels of AChE are higher than those of °ChE. Immediately after hatching the AChE level decreases rapidly in normal plasma, reaching a very low level by 2‐3 weeks ex ovo. The AChE level in plasma from dystrophic birds, although less than normal from day 19 in ovo to 2 weeks ex ovo, subsequently increases to peak around 4 months at levels 15‐20‐fold of those in normal birds. There is virtually no enzyme of either type in the erythrocytes of normal or dystrophic chickens. The changes of AChE in plasma were correlated with the alterations of AChE in dystrophic fast‐twitch muscles, suggesting that the latter pool is a precursor of the plasma AChE. Both the AChE and the °ChE in plasma exist in multiple molecular forms, which are similar to certain of those found previously in the muscles of these birds. The major form (60‐80%) of both enzymes in the plasma is the M form (sedimentation coefficient ≥11 S) in all cases, but it is accompanied by certain other forms. In no case is there any of the heaviest form (H2, 19‐20 S) of AChE or of °ChE found in normal and dystrophic muscle, which is attached at the synapses in normal muscle. The pattern of forms of plasma °ChE is constant at all ages, and in normal and dystrophic chickens. The pattern of forms of AChE in the plasma, in contrast, varies with age and with dystrophy in a characteristic manner. The sedimentation coefficients and the amounts of the enzymes in fast‐twitch muscle of dystrophic animals are compared with those of the plasma forms, and an interpretation is given of the characteristic patterns of AChE and of χE in their blood.

Serum cholinesterases are differentially regulated in normal and dystrophin-deficient mutant mice

“…Elevated levels of serum AChE were also reported for dystrophic chickens (Lyles et al, 1980) and for other animal dystrophies (Skau, 1985), as well as for fetal calf serum (Ralston et al, 1985). Oliver et al (1992) proposed that the increased AChE levels in the sera of the dystrophic mice reflect increased release of muscle AChE relative to release in wt controls.…”

Age-Dependent Changes in Plasma and Brain Cholinesterase Activities of House Wrens and European Starlings

“…Trends in ChE activity in the embryo determine ChE activity in plasma of chicks immediately after hatching (Lyles et al, 1980;Smucker and Wilson, 1990). However, maturation of the blood-brain barrier, which reduces the passage of large, polar molecules, may not be complete for a significant period after hatching (Benzo, 1986).…”

“…In contrast, AChE activity declines rapidly after hatching. Butyrylcholinesterase is apparently synthesized in the liver (Lyles et al, 1980) and an increase in BChE activity in plasma of newly hatched chicks is related to a decline of BChE activity in liver suggesting mobilization and release of BChE from the liver (Smucker and Wilson, 1990). The origin of AChE in plasma is not known but is likely extrahepatic, possibly originating from the central nervous system or developing muscle fibers (Smucker and Wilson, 1990).…”

The Quaternary Structure of Chicken Acetylcholinesterase and Butyrylcholinesterase; Effect of Collagenase and Trypsin

“…I .8.) that parallel those of AChE Lyles et al, , 1980: Each AChE form possesses a BuChE counterpart, which sediments slightly more slowly. In a previous article, we have suggested that the molecular forms of chicken AChE are structurally homologous to those of other vertebrates, such as the electric eel, Efectrophorus, and mammals .…”